O86-01 Consolidated - 2005

A National Standard of Canada(approved January 2003)

CAN/CSA-O86-01

Engineering Design in Wood

Reprinted June 2005. This reprint incorporates replacement pages issued as Update No. 1 (January 2003) and Supplement No. 1 (January 2005) into the original 2001 Standard.

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CAN/CSA-O86-01Engineering Design in Wood

Approved byStandards Council of Canada

Prepared by

ISBN 1-55436-094-3

© Canadian Standards Association — 2001, 2005

All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permission of the publisher.

(Copyright page replaced June 2005)

Reprinted June 2005. This reprint incorporates replacement pages issued as Update No. 1 (January 2003) and Supplement No. 1* (January 2005) into the original 2001 Standard. The superseded pages have been gathered at the end of the Standard for reference. The replacement pages incorporated into the Standard are identified by date. Revisions made in the replacement pages in the body of the Standard are marked by the symbol delta (∆) in the margin.

*Supplement No. 1 contains major changes to make CAN/CSA-O86-01 consistent with the National Building Code of Canada (NBCC), 2005. The changes to Clause 4 of the Standard reflect changes adopted in the 2005 NBCC, including the companion load action approach, the separation of live load and snow load, and the rationalization of importance factors for building types and loads. Clause 4 also provides minimum load criteria for calculating deflection in wood members. Other revisions in the Supplement include increased specified shear values for sawn lumber; revised negative bending moment design values for glued-laminated timber; revisions to design values for structural sheathing OSB; and revisions to the clauses dealing with proprietary structural wood products. Additional information on compression perpendicular to grain capacity has been added in an appendix.

© Canadian Standards Association Engineering Design in Wood

January 2005(Replaces p. iii, August 2001) iii

) Contents

Technical Committee on Engineering Design in Wood ix

Subcommittee on General Design xi

Subcommittee on Sawn Lumber xii

Subcommittee on Glued-Laminated Timber xiii

Subcommittee on Panel Products xiv

Subcommittee on Fastenings xv

Subcommittee on Proprietary Structural Wood Products xvi

Task Force on Seismic Design in Wood xvii

Preface xviii

1. Scope 1

2. Definitions, Symbols, Spacing Dimensions, and Reference Publications 12.1 Definitions 12.2 Symbols 72.3 Spacing Dimensions 102.4 Reference Publications 11

3. Objectives and Design Requirements 143.1 Objective 143.2 Limit States 143.3 Design Requirements 143.3.1 Structural Adequacy 143.3.2 New or Special Systems of Design and Construction 143.3.3 Structural Integrity 143.3.4 Basis of Design 143.3.5 Quality of Work 143.3.6 Design Drawings 14

4. General Design 154.1 Ultimate and Serviceability Limit States 154.1.1 Method of Analysis 154.1.2 Ultimate Limit States 154.1.3 Serviceability Limit States 154.1.4 Resistance Factors 154.2 Specified Loads, Load Effects, and Load Combinations 154.2.1 Buildings 154.2.2 Other Structures 164.2.3 Specified Loads 164.2.4 Load Combinations 164.3 Conditions and Factors Affecting Resistance 17

CAN/CSA-O86-01 Canadian Standards Association

January 2005iv (Replaces p. iv, August 2001)

4.3.1 General 174.3.2 Load Duration Factor, K 18D

4.3.3 Service Condition Factor, K 19S

4.3.4 Preservative and Fire-Retardant Treatment Factor, K 19T

4.3.5 System Factor, K 19H

4.3.6 Size Factor, K 19Z

4.3.7 Lateral Stability Factor, K 19L

4.3.8 Reduction in Cross-Section 194.4 Resistance to Seismic Loads 204.5 Serviceability Requirements 204.5.1 Modulus of Elasticity 204.5.2 Elastic Deflection 204.5.3 Permanent Deformation 204.5.4 Ponding 204.5.5 Vibration 20

5. Sawn Lumber 20A5.1 Scope 20A5.2 Materials 20A5.2.1 Identification of Lumber 20A5.2.2 Lumber Grades and Categories 215.2.3 Finger-Joined Lumber 225.2.4 Remanufactured Lumber 225.2.5 Mixed Grades 225.3 Specified Strengths 225.3.1 Visually Stress-Graded Lumber 225.3.2 Machine Stress-Rated and Machine Evaluated Lumber 235.4 Modification Factors 285.4.1 Load Duration Factor, K 28D

5.4.2 Service Condition Factor, K 28S

5.4.3 Treatment Factor, K 28T

5.4.4 System Factor, K 29H

5.4.5 Size Factor, K 29Z

5.5 Strength and Resistance 315.5.1 General 315.5.2 Sizes 315.5.3 Continuity 315.5.4 Bending Moment Resistance 315.5.5 Shear Resistance 325.5.6 Compressive Resistance Parallel to Grain 355.5.7 Compressive Resistance Perpendicular to Grain 395.5.8 Compressive Resistance at an Angle to Grain 405.5.9 Tensile Resistance Parallel to Grain 405.5.10 Resistance to Combined Bending and Axial Load 415.5.11 Decking 415.5.12 Preserved Wood Foundations 425.5.13 Sawn Lumber Design for Specific Truss Applications 43

6. Glued-Laminated Timber (Glulam) 456.1 Scope 456.2 Materials 456.2.1 Stress Grades 456.2.2 Appearance Grades 456.3 Specified Strengths 45


August 2001 v

6.4 Modification Factors 476.4.1 Load Duration Factor, KD 476.4.2 Service Condition Factor, KS 476.4.3 System Factor, KH 476.4.4 Treatment Factor, KT 476.5 Strength and Resistance 476.5.1 Scope 476.5.2 Orientation 486.5.3 Vertically Glued-Laminated Beams 486.5.4 Net Section 486.5.5 Sizes 486.5.6 Bending Moment Resistance 486.5.7 Shear Resistance 536.5.8 Compressive Resistance Parallel to Grain 586.5.9 Compressive Resistance Perpendicular to Grain (Bearing) 596.5.10 Compressive Resistance at an Angle to Grain 606.5.11 Tensile Resistance Parallel to Grain 606.5.12 Resistance to Combined Bending and Axial Load 60

7. Structural Panels 607.1 Scope 607.2 Materials 617.2.1 Plywood 617.2.2 OSB 617.2.3 Adhesives for Stress Joints 617.3 Specified Capacities 617.3.1 Plywood 617.3.2 OSB 617.4 Modification Factors 707.4.1 Load Duration Factor, KD 707.4.2 Service Condition Factor, KS 707.4.3 Treatment Factor, KT 707.4.4 Stress Joint Factor, XJ 707.4.5 Factor KF for Preserved Wood Foundations 717.5 Resistance of Structural Panels 717.5.1 Stress Orientation 717.5.2 Bending as a Panel 727.5.3 Bending on Edge 727.5.4 Planar Shear 727.5.5 Shear-through-Thickness of Structural Panel 737.5.6 Compression Parallel to Panel Edge 737.5.7 Tension Parallel to Panel Edge 737.5.8 Compressive Resistance Perpendicular to Face (Bearing) 74

8. Composite Building Components 748.1 Scope 748.2 Materials 748.2.1 General 748.2.2 Adhesives for Structural Components 748.2.3 Lumber 748.2.4 Glulam 748.3 Stress Joint Factor, XJ 748.3.1 Joint Requirements 748.3.2 Scarf Joints 74

CAN/CSA-O86-01 © Canadian Standards Association

vi August 2001

8.3.3 Butt Joints 758.4 Construction Requirements for Stress Joints 758.4.1 Types of Stress Joints 758.4.2 Adhesives for Stress Joints 758.4.3 Scarf Joints 758.4.4 Butt Joints 758.5 Plywood and OSB Web Beams 768.5.1 General 768.5.2 Effective Stiffness 768.5.3 Bending Resistance 768.5.4 Web Shear-through-Thickness 778.5.5 Flange-Web Shear 778.5.6 Deflection 788.5.7 Lateral Stability of Panel Web Beams 818.5.8 Stiffeners 818.5.9 Web Stabilizers 818.6 Stressed Skin Panels 818.6.1 General 818.6.2 Effective Stiffness 818.6.3 Bending Resistance 82

9. Shearwalls and Diaphragms 849.1 Scope 849.2 Materials 849.2.1 General 849.2.2 Additional Materials 849.3 Design of Shearwalls and Diaphragms 859.3.1 General 859.3.2 Resistance to Overturning 859.3.3 Shearwalls with Segments 869.3.4 Shearwalls with Multiple Layers 879.3.5 Concrete or Masonry Wall Anchorage 879.3.6 Shearwall Anchorage 879.4 Modification Factors 879.4.1 Load Duration Factor, KD 879.4.2 Service Condition Factor, KSF 889.4.3 Species Factor for Framing Material, Jsp 889.4.4 Strength Adjustment Factor for Unblocked Shearwalls, Jub 889.4.5 Hold-down Effect Factor for Shearwall Segments, Jhd 899.5 Strength and Resistance 909.5.1 Shear Resistance of Nailed Shearwalls 909.5.2 Shear Resistance of Nailed Diaphragms 929.5.3 Nailed Shearwalls and Diaphragms Using Plywood, OSB, or Waferboard 929.5.4 Nailed Shearwalls Using Gypsum Wallboard 929.5.5 Nailed Shearwalls and Diaphragms Using Diagonal Lumber Sheathing 939.5.6 Moment Resistance of Nailed Shearwalls and Diaphragms 939.6 Detailing Requirements 949.6.1 General 949.6.2 Fastenings to Shearwalls and Diaphragms 94

10. Fastenings 9910.1 Scope 9910.2 General Requirements 9910.2.1 All Fastenings 99


January 2005(Replaces p. vii, August 2001) vii

10.2.2 Bolts, Lag Screws, Split Rings, and Shear Plate Connectors (General Requirements) 10110.3 Split Ring and Shear Plate Connectors 10710.3.1 General 10710.3.2 Service Condition Factor 10810.3.3 Distance Factors 10810.3.4 Lumber Thickness 11310.3.5 Lag Screw Connector Joints 11310.3.6 Lateral Resistance 11410.4 Bolts 11510.4.1 General 11510.4.2 Member Thickness 11610.4.3 Placement of Bolts in Joints 11610.4.4 Lateral Resistance 11810.4.5 Combined Lateral and Axial Resistance 12010.5 Drift Pins 12010.5.1 General 12010.5.2 Prebored Holes 12010.5.3 Drift Pin Points 12010.5.4 Drift Pin Length 12010.5.5 Size and Placement of Drift Pins in Joints 12010.5.6 Lateral Resistance 12110.6 Lag Screws 12210.6.1 General 12210.6.2 Placement of Lag Screws in Joints 12210.6.3 Penetration of Lag Screws 12210.6.4 Side Members 12310.6.5 Withdrawal Resistance 12310.6.6 Lateral Resistance 12310.7 Timber Rivets (also known as Glulam Rivets) 12510.7.1 General 12510.7.2 Lateral Resistance 12910.7.3 Withdrawal Resistance 13010.8 Truss Plates 14210.8.1 General 14210.8.2 Design 14310.8.3 Factored Resistance of Truss Plates 14510.8.4 Lateral Slip Resistance 14710.9 Nails and Spikes 14810.9.1 General 14810.9.2 Joint Configuration 14810.9.3 Joint Design 15110.9.4 Lateral Resistance 15110.9.5 Withdrawal Resistance 15210.10 Joist Hangers 15410.10.1 General 15410.10.2 Design 15510.10.3 Factored Resistance of Joist Hangers 155

11. Timber Piling 15511.1 Scope 15511.2 Materials 15611.2.1 Preservative Treatment 15611.2.2 Untreated Piling 15611.3 Specified Strengths 156


January 2005viii (Replaces p. viii, August 2001)

11.4 Modification Factors 15611.5 Strength and Resistance 15611.5.1 General 15611.5.2 Piles as Compression Members 15611.5.3 Effective Length 15611.5.4 Embedded Portion 15611.5.5 Unembedded Portion 157

12. Pole-Type Construction 15712.1 Scope 15712.1.1 Round Poles 15712.1.2 Sawn Timbers 15712.2 Materials 15812.2.1 Preservative Treatment 15812.2.2 Short Poles 15812.3 Specified Strengths 15812.4 Modification Factors 15812.5 Strength and Resistance 15812.5.1 General 15812.5.2 Poles as Compression Members 15812.5.3 Poles as Bending Members 159

13. Proprietary Structural Wood Products 15913.1 Scope 15913.2 Prefabricated Wood 3-Joists 15913.2.1 General 15913.2.2 Materials 15913.2.3 Specified Strengths and Moduli of Elasticity 16013.2.4 Modification Factors 16213.2.5 Strength and Resistance 16313.2.6 Fastenings 16413.3 Type 3 (Proprietary) Design-Rated OSB Panels 16513.3.1 Manufacture 16513.3.2 Panel Identification and Certificates of Conformance 16513.3.3 Basic Structural Capacities 16513.3.4 Specified Capacities 16513.3.5 Design Methods 16513.4 Structural Composite Lumber Products 16613.4.1 General 16613.4.2 Adhesives and Binder Systems 16613.4.3 Specified Strengths and Moduli of Elasticity 16613.4.4 Modification Factors 16713.4.5 Strength and Resistance 16813.4.6 Fastenings 171

Appendix A — Additional Information and Alternative Procedures 173


August 2001 ix

Technical Committee on EngineeringDesign in Wood

C.R. Wilson Carl R. Wilson & Associates Ltd., ChairVancouver, British Columbia

G.C. Williams Timber Systems Limited, Vice-ChairMarkham, Ontario

P. Trott Canadian Wood Council, SecretaryOttawa, Ontario

J.D. Barrett University of British Columbia,Vancouver, British Columbia

S. Boyd Quaile Engineering Ltd.,Newmarket, Ontario

Y.H. Chui Wood Science and Technology Centre,Fredericton, New Brunswick

D.E. Darby Alberta Agriculture, Food and Rural Development,Lethbridge, Alberta

B. Di Lenardo NRC-Canadian Construction Materials Centre,Ottawa, Ontario

G.A. Dring G.A. Dring and Associates,Boissevain, Manitoba

R.A. Hewett Hewett Consulting,Nepean, Ontario

D. Himmelfarb Timber West Engineering Ltd.,Edmonton, Alberta

B. Hintz Jager Industries Inc.,Calgary, Alberta

M.J. Janotta Town of Richmond Hill, Building Services Division,Richmond Hill, Ontario

D. Janssens Structural Board Association,Willowdale, Ontario

K.C. Johns Université de Sherbrooke,Sherbrooke, Québec


x August 2001

E. Jones Canadian Wood Council,Ottawa, Ontario

E. Karacabeyli Forintek Canada Corp.,Vancouver, British Columbia

T.V. Leung Thomas Leung Structural Engineering Inc.,Vancouver, British Columbia

B. Madsen Timber Engineering Ltd.,North Vancouver, British Columbia

R. Malczyk Equilibrium Consulting Inc.,Vancouver, British Columbia

N. Nagy Canadian Plywood Association,North Vancouver, British Columbia

P. Quenneville Royal Military College,Kingston, Ontario

D. Rice Trus Joist Technology Center,Boise, Idaho, USA

M. Rufiange Structurlam Products Ltd.,Penticton, British Columbia

I. Smith University of New Brunswick,Fredericton, New Brunswick

R. Tiller Structural Design Inc.,St. John’s, Newfoundland

M.R. Lottamoza CSA, Project ManagerToronto, Ontario


August 2001 xi

Subcommittee on General Design

K.C. Johns Université de Sherbrooke, ChairSherbrooke, Québec





M.J. Janotta Town of Richmond Hill,Building Services Division,Richmond Hill, Ontario


F. Lam University of British Columbia,Vancouver, British Columbia



G.C. Williams Timber Systems Limited,Markham, Ontario


xii August 2001

Subcommittee on Sawn Lumber

J.D. Barrett University of British Columbia, ChairVancouver, British Columbia



B. Craig Trus Joist,Delta, British Columbia

D.E. Darby Alberta Agriculture, Food and Rural Development,Lethbridge, Alberta

S. Goldie Vancouver, British Columbia

R.A. Hewett Hewett Consulting,Nepean, Ontario

B. Hintz Jager Industries Inc.,Calgary, Alberta

M.J. Janotta Town of Richmond Hill, Building Services Division,Richmond Hill, Ontario




C. Lum Forintek Canada Corp.,Vancouver, British Columbia


A. Rozek National Lumber Grades Authority,New Westminster, British Columbia


August 2001 xiii

Subcommittee on Glued-LaminatedTimber

D. Himmelfarb Timber West Engineering Ltd., ChairEdmonton, Alberta





M. Rufiange Structurlam Products Ltd.,Penticton, British Columbia


B. Yeh APA,Tacoma, Washington, USA


xiv August 2001

Subcommittee on Panel Products

D. Janssens Structural Board Association, ChairWillowdale, Ontario



D. Gromala Weyerhaeuser Corp.,Tacoma, Washington, USA


P. Lau Alpa Roof Truss Inc.,Maple, Ontario

M. Lepper Canadian Wood Council,Ottawa, Ontario

J. Lowood Lowood Enterprises,Delta, British Columbia


D. Onysko DMO Associates,Orléans, Ontario

C. Robinson Intertek Testing Services,Coquitlam, British Columbia

J. Scarlett Jager Industries Inc.,Calgary, Alberta

S. Zylkowski APA,Tacoma, Washington, USA


August 2001 xv

Subcommittee on Fastenings

P. Quenneville Royal Military College, ChairKingston, Ontario






K. Koo Jager Industries Inc.,Bolton, Ontario

P. Lau Alpa Roof Truss Inc.,Maple, Ontario

M. Lepper Canadian Wood Council,Ottawa, Ontario


D. Onysko DMO Associates,Orléans, Ontario

H. Prion University of British Columbia,Vancouver, British Columbia

D. Rice Trus Joist Technology Center,Boise, Idaho, USA




xvi August 2001

Subcommittee on ProprietaryStructural Wood Products

D. Rice Trus Joist Technology Center, ChairBoise, Idaho, USA

R. Desjardins Forintek Canada Corp.-Eastern Division,Ste-Foy, Québec


S. Goldie Vancouver, British Columbia

B. Haley Weldwood Engineered Wood Products,Calgary, Alberta

T. Hoffman ITS-Warnock Hersey,Coquitlam, British Columbia



J. Scarlett Jager Industries Inc.,Calgary, Alberta

D. Soderquist Willamette Industries Inc.,Woodburn, Oregon, USA

B. Yeh APA,Tacoma, Washington, USA


August 2001 xvii

Task Force on Seismic Design inWood

E. Karacabeyli Forintek Canada Corp., ChairVancouver, British Columbia

C. Chiu Chiu Engineering,Vancouver, British Columbia





G. Newfield Read Jones Christofferson,Vancouver, British Columbia

C. Ni Forintek Canada Corp.,Vancouver, British Columbia

H. Prion University of British Columbia,Vancouver, British Columbia


R. Tiller Structural Design Inc.,St. John’s, Newfoundland


xviii August 2001

Preface

This is the eighth edition of CSA Standard O86, Engineering Design in Wood. It is written in limit states design (LSD) format and supersedes the previous editions, published in 1994, 1989, 1984, 1980, 1976, 1970, and 1959, including their Supplements.

Editions of CSA Standard O86 published in 1959, 1970, 1976, 1980, and 1984 were all developed using working stress design (WSD) theory. The last WSD version, CSA Standard CAN3-O86-M84, Engineering Design in Wood (Working Stress Design), existed concurrently with the first (1984) and second (1989) limit states design (LSD) versions, Engineering Design in Wood (Limit States Design). The WSD version was withdrawn on publication of the 1994 LSD edition.

Three previous LSD editions were published in 1984, 1989, and 1994 with the CSA designation O86.1. Supplements to each of these editions were published in 1987, 1993, and 1998, respectively. Although this new edition continues to be based on the LSD method, the O86 designation has been reinstituted.

Major revisions in this 2001 edition are included in Clause 9, where specified strengths have been expanded to provide for construction OSB and gypsum. A mechanics-based design procedure has been included to provide criteria for shearwall segments with and without hold-downs and anchorages for shearwalls constructed of dissimilar materials of two layers, of two sides, and of blocked and unblocked diaphragms. In addition, more flexibility has been included for using the factors accounting for fastener capacities.

Other revisions include:(a) for sawn lumber, additional guidance on dealing with vibration and elastic deflection of systems,

revised notch criteria, and specified strengths for 89 × 89 mm light framing;(b) for glulam, bending size factor for beams;(c) for structural panels, specified strengths and modulus of elasticity for CSA O325 OSB and reference to

panel mark equivalency;(d) for composite building components, revised stress joint factors and engineering basis for the use of

panels; and(e) for connections, inclusion of withdrawal resistance for nails and spikes, design criteria for anchor bolts

in concrete capacities, and updated references to truss plates standards.Other minor revisions and refinements are found throughout the document, including the clauses

dealing with proprietary structural wood products, the harmonization of the treatment factor for all materials, the design of preserved wood foundations, and the design of trusses.

This Standard was prepared by the Technical Committee on Engineering Design in Wood, under the jurisdiction of the Strategic Steering Committee on Structures (Design), and has been formally approved by the Technical Committee. This Standard has been approved as a National Standard of Canada by the Standards Council of Canada.

August 2001

Notes: (1) Use of the singular does not exclude the plural (and vice versa) when the sense allows.(2) Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains

the responsibility of the users of the Standard to judge its suitability for their particular purpose.(3) This publication was developed by consensus, which is defined by CSA Policy governing standardization — Code of

good practice for standardization as “substantial agreement. Consensus implies much more than a simple majority, but not necessarily unanimity”. It is consistent with this definition that a member may be included in the Technical Committee list and yet not be in full agreement with all clauses of this publication.

(4) CSA Standards are subject to periodic review, and suggestions for their improvement will be referred to the appropriate committee.

(5) All enquiries regarding this Standard, including requests for interpretation, should be addressed to Canadian Standards Association, 5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6.


August 2001 xix

Requests for interpretation should(a) define the problem, making reference to the specific clause, and, where appropriate, include an illustrative sketch;(b) provide an explanation of circumstances surrounding the actual field condition; and(c) be phrased where possible to permit a specific “yes” or “no” answer.

Committee interpretations are processed in accordance with the CSA Directives and guidelines governingstandardization and are published in CSA’s periodical Info Update, which is available on the CSA Web site atwww.csa.ca.


August 2001 1

CAN/CSA-O86-01Engineering Design in Wood

1. ScopeThis Standard provides criteria for the structural design and appraisal of structures or structural elementsmade from wood or wood products, including graded lumber, glued-laminated timber, unsandedplywood, oriented strandboard (OSB), composite building components, shearwalls and diaphragms,timber piling, pole-type construction, prefabricated wood I-joists, structural composite lumber products,preserved wood foundations, and their structural fastenings. The Standard employs the limit statesdesign method.

2. Definitions, Symbols, Spacing Dimensions, and ReferencePublications

2.1 DefinitionsThe following definitions apply in this Standard:

Adhesive (glue) — a substance capable of holding materials together by surface attachment forstructural purposes.

Analogue member — the line representation of a truss member for the purposes of structural analysis.

Aspect ratio of a shearwall segment — the ratio of the height to the length of the segment.

Basic structural capacity — the numeric result of certain calculations specified inCSA Standard O452.0 to characterize the short-term mechanical engineering properties (at EMC at20EC/80% RH) of a product, such as tensile capacity or shear capacity, based on test results for a sampleundergoing qualification testing, and used to establish the specified capacities of design-rated OSB.

Beam — a timber whose larger dimension exceeds its smaller dimension by at least 51 mm; the beam isusually graded for use in bending with the load applied to the narrow face. (Grading rules sometimesdesignate beams as “beams and stringers”.)

Board — a piece of lumber that is less than 38 mm in its smaller dimension.

Butt joint — a square joint between the ends of two pieces of wood or panel.

Capacity — in relation to prefabricated wood 3-joists or structural composite lumber, the numeric valuedetermined from strength and stiffness test data by calculations specified in ASTM Standard D 5055 orD 5456, respectively, carried out to characterize strength properties of 3-joists or structural compositelumber or their component materials. The term is used in combination with a specific property, such astensile capacity or shear capacity.Note: See also Specified capacity and Basic structural capacity for the term’s application to panel products.

Certificate of conformance — a document applicable to a design-rated OSB product issued by thecertification organization. It certifies that the product meets the requirements of CSA Standard O452Series and identifies its specified capacities determined in accordance with CSA Standard O452 Series.


2 August 2001

Certification organization (C.O.) — an impartial body possessing the necessary competence andreliability to operate a certification system in which the interests of all parties concerned with thefunctioning of the system are represented, and accredited as such by agencies having a nationalmandate to accredit certification organizations operating within their countries’ borders.Note: The Standards Council of Canada (SCC) has a national mandate to accredit certification organizations foroperation in Canada.

Concentrically braced heavy timber space frame — a structural system with an essentiallycomplete timber space frame providing support for gravity loads and diagonal bracing with ductileconnections resisting lateral loads.

Density — mass per unit volume. In the case of wood, density is usually expressed as kilograms percubic metre at a specified moisture content.

Design rating — a grade mark (consisting of a nominal thickness and a rating grade) assigned to aqualified OSB panel that indicates the panel’s suitability for engineering design construction and thatdenotes a specific set of engineering property values for that panel.

Diaphragm — a horizontal or nearly horizontal system that acts to transmit lateral forces to the verticalresisting elements. The term “diaphragm” includes horizontal bracing systems.

Dimension lumber — lumber 38 to 102 mm, inclusive, in its smaller dimension.

Documented — having written technical substantiation that the use of a particular material, design,practice, or construction method satisfies the intent of this Standard.

Dressed size — the cross-sectional dimensions in millimetres of lumber after planing.

Drift pin — a round mild steel bar, without head or threads, used to provide a laterally loadedconnection between overlapping timbers in heavy engineering structures such as cribwork.

Edge distance — the distance from the edge of the member to the centre of the nearest fastening.

End distance — the distance measured parallel to the axis of a piece from the centre of a fastening tothe square-cut end of the member. In the case of a connector, if the end of the member is not square-cut, the end distance is taken from any point on the centre half of the connector diameter drawnperpendicular to the centreline of the piece to the nearest point on the end of the member measuredparallel to the axis of the piece (see Figures 10.3.3A and 10.3.3B).

Equilibrium moisture content — the moisture content at which wood or wood products neithergain nor lose moisture when surrounded by air at a given relative humidity and temperature.

Factored load — the product of a specified load and its applicable load factor.

Factored resistance — the product of resistance and its applicable resistance factor.

Fibre saturation point — the moisture content at which the cell walls are saturated and the cellcavities are free of water; approximately 25–30% moisture content.

Flat truss — a truss in which the slope of the top chord does not exceed 2 in 12.

Girder truss — a truss that is used as a main supporting member for secondary framing systems such asother trusses, joists, or rafters.


August 2001 3

Glue — see Adhesive.

Glued-laminated timber (glulam) — see Structural glued-laminated timber.

Grade — the designation of the quality of a piece of wood.

Hold-down connection — a connection at the corner of a shearwall or shearwall segment that isdesigned to provide a structural load path between the boundary chords of the segment and (a) the foundation or beam supporting the shearwall; or(b) the corresponding chord member of the shearwall segment above or below.

Importance factor, ( — a factor applied to the factored loads other than dead load to take intoaccount the consequences of collapse as related to the use and occupancy of the structure.

Joist — a piece of dimension lumber 114 mm or more in its larger dimension, intended to be loaded onits narrow face.

Lamination — a thin element of wood of appreciable width and length consisting of one or morepieces that may be joined end-to-end.

Limit state — a condition of a structure in which the structure ceases to fulfill the design function.

Load combination factor, Q — a factor applied to the factored loads other than dead load to takeinto account the reduced probability of a number of loads from different sources acting simultaneously.

Load duration — the period of continuous application of a given load or the aggregate of periods ofintermittent applications of the same load.

Load factor, " — a factor applied to a specified load that, for the limit state under consideration, takesinto account the variability of the loads and load patterns.

Lumber —

Machine evaluated lumber — structural lumber that has been graded by means of anondestructive test and visual grading, conforming to the requirements for machine stress-rated lumber,with the exception that the process lower fifth percentile modulus of elasticity (MOE) equals or exceeds0.75 times the characteristic mean MOE for the grade.

Machine stress-rated lumber — structural lumber graded by means of a nondestructive test andvisual grading, in accordance with the requirements of CSA Standard CAN/CSA-O141.

Rough lumber — lumber as it comes from the saw.

Sawn lumber — the product of a sawmill not further manufactured other than by sawing, resawing,passing lengthwise through a standard planing mill, and cross-cutting to length.

Structural lumber — lumber in which strength is related to the anticipated end use as a controllingfactor in grading or selecting.

Visually stress-graded lumber — structural lumber that has been graded in accordance with theprovisions of the NLGA Standard Grading Rules for Canadian Lumber.

Lumber sizes — under the metric system(a) rough lumber is designated by its actual dry or green size;


4 August 2001

(b) dressed dry (S-Dry) lumber is designated by its actual finished size;(c) dressed green (S-Grn) dimension lumber is designated by its anticipated dry size at 19% moisturecontent;(d) dressed green timber is designated by its actual green size; and(e) sizes are rounded to the nearest millimetre.

Major axis (major strength axis) — the axis with the greater stiffness and strength in bending: forplywood, the direction parallel to the face grain; for OSB, the direction of alignment of the strands in theface layers of the panel.

Mid-panel moment — the maximum moment between panel points.

Minor axis (minor strength axis) — the axis with the lesser stiffness and strength in bending: forplywood, the direction perpendicular to the face grain; for OSB, the direction perpendicular to thealignment of the strands in the face layers of the panel.

Moisture content — the mass of water in wood expressed as a percentage of the mass of the oven-drywood.

Moment-resisting wood space frame — a structural system with an essentially complete woodspace frame providing support for gravity loads, with resistance to lateral loads provided primarily byflexural action of members.

Nailed shear panel — a nailed diaphragm or a nailed shearwall.

OSB — an acronym for oriented strandboard: that is, a strandboard panel containing layers of alignedstrands, generally with the strands in the face layers aligned in the direction of the panel length. Panelsare marked to show the direction of alignment of face layers.

Construction sheathing OSB — OSB that has been certified to CSA Standard CAN/CSA-O325.0for protected construction uses such as roof sheathing, wall sheathing, and floor sheathing in light frameconstruction applications and other permitted engineering applications in this Standard.

CSA O437 OSB — OSB that meets the requirements of CSA Standard O437.0 (Grade O-2 or O-1)and that is recognized for use as sheathing for shearwalls and diaphragms within this Standard.

Design-rated OSB — OSB panels qualified and certified for use in engineering design constructionin accordance with CSA Standard O452 Series.

Type 1: STANDARD — design-rated OSB meeting the minimum basic structural capacity valuesset in CSA Standard O452.0 for the rating grade.

Type 2: PLUS — design-rated OSB having one or more properties assigned higher basicstructural capacity values, in percentage, than the minimum set for the rating grade of the product.

Type 3: PROPRIETARY — design-rated OSB with assigned proprietary specified capacity valuesdetermined in accordance with Clause 13.3.

Panel length — with respect to the design of lumber members in metal-plated trusses (seeClause 5.5.13), the distance between two adjacent panel points.

Panel point — with respect to the design of lumber members in metal-plated trusses (seeClause 5.5.13), a point representing the intersection of two or more analogue member lines and/or anormal line from a bearing surface.


August 2001 5

Panel point moment — with respect to the design of lumber members in metal-plated trusses (seeClause 5.5.13), the moment computed at an analogue panel point.

Perimeter member — an element at edges of openings or at perimeters of shearwalls or diaphragms.

Pitch — the rise in run, usually expressed as a fraction of 12, of the upper surface of a roof member.

Pitch break — the point at which a truss chord member changes slope.

Planar shear — the shear that occurs in the plane of the panel. Also referred to as “shear-in-plane”.

Plank — a piece of dimension lumber 114 mm or more in its larger dimension, intended to be loadedon its wide face.

Ply — a thin layer or sheet of wood (veneer), or several pieces laid with adjoining edges that may ormay not be edge-glued, forming one layer in a plywood panel.

Plywood —

Regular unsanded grade — any one of the following three grades: Select-Tight Face, Select, orSheathing as defined in CSA Standards O121 and O151.

Standard construction — panels that meet the requirements for standard constructions as definedin CSA Standards O121 and O151 and Clause A7.3.1 of this Standard.

Pole-type construction — a form of construction in which the principal vertical members are roundpoles or sawn timbers embedded in the ground and extending vertically above ground to provide bothfoundation and vertical framing members for the structure.

Post — a timber with its larger dimension not more than 51 mm greater than the smaller dimension,usually graded for use as a column. (Grading rules sometimes designate posts as “posts and timbers”.)

Prefabricated wood I-joist — a structural member manufactured using structural lumber, structuralglued-laminated timber, or structural composite lumber flanges, and structural panel webs, bondedtogether with exterior exposure adhesives, forming an “3” cross-sectional shape.Note: To avoid confusion with plywood web beams as defined in Clause 8.5, “prefabricated wood 3-joist” refers tohigh-volume, mass-produced proprietary products primarily used as joists in the construction of floor and roof systems.

Resistance factor, N — a factor applied to the resistance of a member or connection for the limit stateunder consideration, which takes into account the variability of dimensions and material properties,quality of work, type of failure, and uncertainty in the prediction of resistance.

Service condition —

Dry service condition — a climatic condition in which the average equilibrium moisture content ofsolid wood over a year is 15% or less and does not exceed 19%.

Wet service condition — all service conditions other than dry.

Serviceability limit states — those states which restrict the intended use and occupancy of thestructure; they include deflection, joint slip, vibration, and permanent deformation.

Shearwall — a stud wall system designed to resist lateral forces parallel to the plane of the wall(sometimes referred to as a vertical diaphragm or a structural wall). A shearwall may consist of one ormore shearwall segments in the plane of the wall.


6 August 2001

Shearwall segment — a section of a shearwall with uniform construction that forms a structural unitdesigned to resist lateral forces parallel to the plane of the wall.

Shrinkage — the decrease in the dimensions of wood or wood products due to a decrease of moisturecontent.

Slab floor — a basement floor system in which a concrete slab or equivalent provides lateral support atthe bottom of the foundation studs.

Slenderness ratio for beams — the ratio used in lateral stability calculations of a bending member.

Slenderness ratio for compression members — the ratio of the effective length of a compressionmember to its actual dimensions.

Slip resistance of a connection — a serviceability state; a resistance that corresponds to a specificlevel of slip.

Space frame — a three-dimensional structural system without structural stud walls that is composed ofmembers interconnected so as to function as a complete self-contained unit with or without the aid ofhorizontal diaphragms or floor bracing systems.

Spacing of fastenings — the distance between fastenings measured between centres.

Specified capacity — the assigned strength capacity, or stiffness or rigidity capacity, for use in theprediction of strength resistance or deflection.

Specified loads — those loads defined in the appropriate building code, or those loads determined byuse and occupancy for structures other than buildings, or such larger loads as may be selected for thedesign.

Specified strength — the assigned strength for use in the prediction of strength resistance.

Stiffener — a piece of wood of rectangular cross-section that extends between the inner surfaces of thetop and bottom flanges of a plywood web beam, and is glued or otherwise fastened to the webs.

Strandboard — a mat-formed structural panel made of specialized wood wafers having a length atleast twice their width.

Strength limit states — those states concerning safety, including the maximum load-carryingcapacity, overturning, sliding, fracture, and deterioration.

Strength resistance of a connection — a resistance based on the geometry and on the ultimateload-carrying capacity of the structural materials of a connection.

Stressed skin panel — a form of construction in which the outer skin, in addition to its normalfunction of providing a surface covering, acts integrally with the frame members, contributing to thestrength of the unit as a whole.

Structural composite lumber — the wood product that is either laminated veneer lumber (LVL) orparallel strand lumber (PSL), manufactured for use in structural applications and bonded with exteriorexposure adhesives.

Laminated veneer lumber (LVL) — a composite of wood veneer sheet elements and adhesivemanufactured with wood fibres primarily oriented along the length of the member. The veneerelements do not exceed 6.4 mm in thickness.


August 2001 7

Parallel strand lumber (PSL) — a composite of wood strand elements and adhesive manufacturedwith wood fibres primarily oriented along the length of the member. The strand elements do notexceed 6.4 mm in thickness and have an average length of at least 150 times their least dimension.

Structural glued-laminated timber — the wood product that is made by bonding under pressuregraded laminating stock whose grain is essentially parallel and that meets the requirements of CSAStandard CAN/CSA-O122.

Structural panel — in this Standard, plywood and OSB panels of specific grades and quality to whichspecified capacities have been assigned, or are assignable, e.g., standard constructions of regular gradesof unsanded Douglas Fir plywood and Canadian Softwood plywood manufactured and marked inaccordance with CSA Standards O121 and O151, and design-rated OSB manufactured, marked, andcertified for use in engineered design construction in accordance with CSA Standard O452.0.

Stud wall system — a structural system without a complete vertical load-carrying space frame. Studwalls provide support for all gravity loads. Studs are spaced not more than 610 mm on centre.

Suspended floor — a basement floor system in which a floor assembly is attached to continuousfoundation studs at a point above the bottom of the studs.

Timber — a piece of lumber 114 mm or more in its smaller dimension.

Timber connector — a metal ring or plate that, by being embedded in adjacent wood faces or in onewood face, acts in shear to transmit loads from one timber to another or from a timber to a bolt and, inturn, to a steel plate or another connector.

Truss plate — a light steel plate fastening, intended for use in structural lumber assemblies, that mayhave integral teeth of various shapes and configurations.

Waferboard — a mat-formed structural panel made predominantly of wood wafers of a minimum andcontrolled length, a controlled thickness, and a variable or predetermined width, bonded together witha waterproof and boilproof binder. Waferboard meets the requirements of CSA Standard O437.0 (GradeR-1) and is recognized for use as sheathing for shearwalls and diaphragms within this Standard.

Wood preservation —

Preservative treatment — impregnation under pressure with a wood preservative.

Wood preservative — any suitable substance that is toxic to fungi, insects, borers, and other livingwood-destroying organisms.

2.2 SymbolsThe following symbols are used throughout this Standard. Deviations from these usages and additionalnomenclature are noted where they appear.

A = cross-sectional area, mm2

Ab = bearing area, mm2

Ag = gross cross-sectional area, mm2

An = net cross-sectional area, mm2

Ba = specified axial stiffness of structural panels, N/mm (Tables 7.3A, 7.3B, 7.3C, and 7.3D)

Bb = specified bending stiffness of structural panels, N•mm2/mm (Tables 7.3A, 7.3B, 7.3C, and 7.3D)


8 August 2001

Br = factored buckling resistance for plywood assemblies, kN/m2 (Clause A8.6.3.4)

Bv = specified shear-through-thickness rigidity of structural panels, N/mm (Tables 7.3A, 7.3B, 7.3C,and 7.3D)

b = width of member, mm

bp = width of structural panel, mm

CB = slenderness ratio for bending members

CC = slenderness ratio for compression members

d = depth of member, mm

dF = diameter of fastening, mm

dp = depth of structural panel in plane of bending, mm

E = specified modulus of elasticity, MPa

E05 = modulus of elasticity for design of compression members, MPa

ES = modulus of elasticity for stiffness calculations, MPa (Clause 4.5.1)

(E3)e = effective stiffness of structural panel assemblies, N•mm2 (Clause 8.5.2 and 8.6.2)

fb = specified strength in bending, MPa

fc = specified strength in compression parallel to grain, MPa

fcp = specified strength in compression perpendicular to grain, MPa

ff = specified notch shear force resistance, MPa

ft = specified strength in tension parallel to grain at net section, MPa

ftg = specified strength in tension parallel to grain at gross section of glued-laminated timber, MPa

ftp = specified strength in tension perpendicular to grain, MPa

fv = specified strength in shear, MPa

3 = moment of inertia, mm4

J = factors affecting capacity of fastenings, used with appropriate subscripts (Clause 10)

Jhd = hold-down effect factor for shearwall segments (Clause 9.4.5)

KB = bearing factor (Clause 5.5.7.6)

KC = slenderness factor for compression members (Clauses 5.5.6.2.3 and 6.5.8.5)

KD = load duration factor (Clause 4.3.2 and Table 4.3.2.2)

KE = end fixity factor for spaced compression members (Clause A5.5.6.3.7)

KF = foundation factor for plywood (Clause 7.4.5)

KH = system factor (Clause 4.3.5)

KL = lateral stability factor for bending members (Clause 4.3.7)

KM = bending capacity modification factor (Clause 5.5.13.5)

KN = notch factor (Clauses 5.5.5.4 and 6.5.7.2.2)

KR = radial stress factor (Clause 6.5.6.6.3)

KS = service condition factor for sawn lumber, glued-laminated timber, plywood, design-rated OSB,poles, and piling (Clause 4.3.3)


January 2005(Replaces p. 9, August 2001) 9

K = service condition factor for bendingSb

K = service condition factor for compression parallel to grainSc

K = service condition factor for compression perpendicular to grainScp

K = service condition factor for modulus of elasticitySE

K = service condition factor for fasteningSF

K = service condition factor for tension parallel to grainSt

K = service condition factor for tension perpendicular to grainStp

K = service condition factor for shearSv

K = treatment factor (Clause 4.3.4.1)T

K = curvature factor for glued-laminated timber (Clause 6.5.6.5.2)X

K = size factor (Clause 5.4.5 and Table 5.4.5)Z

K = size factor for bending for sawn lumberZb

K = size factor for bending for glued-laminated timber (Clause 6.5.6.5.1)Zbg

K = size factor for compression for sawn lumber (Clauses 5.5.6.2.3 and 5.5.13.3.3)Zc

K = size factor for compression for glued-laminated timber (Clause 6.5.8.4.2)Zcg

K = size factor for bearing (Clauses 5.5.7.5 and 6.5.9.2)Zcp

K = size factor for tension for sawn lumberZt

K = size factor for tension perpendicular to grain for glued-laminated timber (Table 6.5.6.6.1)Ztp

K = size factor for shear for sawn lumber (Clause 5.4.5.3)Zv

L = length, mm

L = effective length, mme

L = length of penetration of fastening into main member, mmp

= span, mm

M = factored bending moment, N•mmf

M = factored bending moment resistance, N•mmr

m = specified strength capacity of structural panels in bending, N•mm/mm (Tables 7.3A, 7.3B, 7.3C,p

and 7.3D)

N = factored compressive resistance at an angle to grain, N; orr

= factored lateral strength resistance of fastenings at an angle to grain, N or kN

N = factored lateral slip resistance of fastenings at an angle to grain, Nrs

N = lateral slip resistance of fastenings at an angle to grain, Ns

N = lateral strength resistance of fastenings at an angle to grain, N or kNu

n = number of fastenings in a groupF

P = factored axial load in compression, Nf

P = factored compressive resistance parallel to grain, N; orr

= factored lateral strength resistance of fastenings parallel to grain, N or kN

P = factored lateral slip resistance of fastenings parallel to grain, Nrs


January 200510 (Replaces p. 10, August 2001)

P = factored withdrawal resistance of fastenings from side grain, Nrw

P = lateral strength resistance of fastenings parallel to grain, N or kNu

p = specified strength capacity of structural panels in axial compression, N/mm (Tables 7.3A, 7.3B,p

7.3C, and 7.3D)

Q = factored compressive resistance perpendicular to grain or to plane of plies, N; orr

= factored lateral strength resistance of fastenings perpendicular to grain, N or kN

Q = factored lateral slip resistance of fastenings perpendicular to grain, Nrs

Q = lateral strength resistance of fastenings perpendicular to grain, N or kNu

q = specified strength capacity of structural panels in bearing, MPa (Tables 7.3A, 7.3B, 7.3C, and 7.3D)p

R = radius of curvature at centreline of member, mm (Figure 6.5.6.6.3)

S = section modulus, mm3

T = factored axial load in tension, Nf

T = factored tensile resistance parallel to grain, Nr

t = specified strength capacity of structural panels in axial tension, N/mm (Tables 7.3A, 7.3B, 7.3C,p

and 7.3D)

V = factored shear force, Nf

V = factored basic shear resistance calculated with J = 1.0, kN (Clause 9.4.5)hd hd

V = factored shear resistance, N; orr

= factored shear-through-thickness resistance of structural panels, N

V = factored planar shear resistance of structural panels, Nrp

V = factored shear resistance of a shearwall segment, kN (Clause 9.5)rs

v = specified strength capacity of structural panels in shear-through-thickness, N/mm (Tables 7.3A,p

7.3B, 7.3C, and 7.3D)

v = specified strength capacity of structural panels in planar shear (due to bending), N/mmpb

(Tables 7.3A, 7.3B, 7.3C, and 7.3D)

v = specified strength capacity of structural panels in planar shear (due to in-plane forces), MPapf

(Tables 7.3A, 7.3B, 7.3C, and 7.3D)

W = factored total load, Nf

w = specified total uniformly distributed load, kN/m2

X = factors affecting capacities of plywood and plywood assemblies, used with appropriate subscripts(Clause 8)

Z = volume, m3

) ( — Deleted

φ = resistance factor

) R — Deleted

2.3 Spacing DimensionsFor the purpose of this Standard, the following apply:(a) Centre-to-centre member spacing dimensions may be used interchangeably:

(i) 300 mm and 305 mm;



(ii) 400 mm and 406 mm; and(iii) 600 mm and 610 mm.

(b) Panel dimensions may be used interchangeably:(i) 1200 mm and 1220 mm; and(ii) 2400 mm and 2440 mm.

) 2.4 Reference PublicationsThis Standard refers to the following publications and where such reference is made it shall be to theedition listed below, including all amendments published thereto.

CSA StandardsB111-1974 (R2003), Wire Nails, Spikes, and Staples;

G40.20-04/G40.21-04,General requirements for rolled or welded structural quality steel/Structural quality steel;

CAN/CSA-O15-90 (R2004), Wood Utility Poles and Reinforcing Stubs;

CAN3-O56-M79 (R2001), Round Wood Piles;

O80 Series-97 (R2002), Wood Preservation;

O80.15-97 (R2002),Preservative Treatment of Wood for Building Foundation Systems, Basements, and Crawl Spaces by PressureProcesses;

O112 Series-M1977 (R2001),CSA Standards for Wood Adhesives;

O112.6-M1977 (R2001), Phenol and Phenol-Resorcinol Resin Adhesives for Wood (High-Temperature Curing);

O112.7-M1977 (R2001), Resorcinol and Phenol-Resorcinol Resin Adhesives for Wood (Room- and Intermediate-Temperature Curing);

O112.9-04, Evaluation of adhesives for structural wood products (exterior exposure);

O121-M1978 (R2003), Douglas Fir Plywood;

CAN/CSA-O122-M89 (R2003), Structural Glued-Laminated Timber;

CAN/CSA-O141-91 (R2004), Softwood Lumber;

O151-M1978 (R2003), Canadian Softwood Plywood;

O153-M1980 (R2003),Poplar Plywood;



CAN/CSA-O177-M89 (R2003), Qualification Code for Manufacturers of Structural Glued-Laminated Timber;

O322-02, Procedure for Certification of Pressure-Treated Wood Materials for Use in Preserved Wood Foundations;

CAN/CSA-O325.0-92 (R2003),Construction Sheathing;

O437 Series-93 (R2001),Standards on OSB and Waferboard;

O437.0-93 (R2001), OSB and Waferboard;

O452 Series-94 (R2001),Design Rated OSB;

O452.0-94 (R2001), Design Rated OSB: Specifications;

S307-M1980 (R2001),Load Test Procedure for Wood Roof Trusses for Houses and Small Buildings;

S347-99 (R2004), Method of Test for Evaluation of Truss Plates Used in Lumber Joints;

CAN/CSA-S406-92 (R2003), Construction of Preserved Wood Foundations.

ANSI/ASME* Standard B18.2.1-1996,Square and Hex Bolts and Screws, Inch Series.

ASTM† StandardsA 36/A 36M-04, Carbon Structural Steel;

A 47/A 47M-99, Ferritic Malleable Iron Castings;

A 307-03, Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength;

A 653/A 653M-03,Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-DipProcess;Note: ASTM Standards A 653/A 653M replace ASTM Standards A 446/A 446M. Their chemical and mechanicalrequirements are the same.

C 36/C 36M-03,Gypsum Wallboard;

C 1002-01,Steel Self-Piercing Tapping Screws for the Application of Gypsum Panel Products or Metal Plaster Bases to WoodStuds or Steel Studs;



D 1761-88 (2000),Mechanical Fasteners in Wood;

D 5055-04,Establishing and Monitoring Structural Capacities of Prefabricated Wood I-Joists;

D 5456-01,Evaluation of Structural Composite Lumber Products;

D 5457-93 (1998),Computing the Reference Resistance of Wood-Based Materials and Structural Connections for Load andResistance Factor Design;

E 8-04,Standard Test Methods for Tension Testing of Metallic Materials.

Canadian Geotechnical Society PublicationCanadian Foundation Engineering Manual, 1992.

Canadian Wood CouncilCWC, Commentary, 2001 (in Wood Design Manual);

Standard Practice Relating Specified Strengths of Structural Members to Characteristic Structural Properties,April 2001.

National Research Council CanadaCCMC Registry of Product Evaluations (published annually);

National Building Code of Canada, 2005;

User’s Guide — NBC 2005 Structural Commentaries (Part 4).

NIST‡ StandardPS2-92,Performance Standard for Wood-Based Structural-Use Panels.

NLGA§ PublicationsStandard Grading Rules for Canadian Lumber, 2003;

SPS 1-2003, Special Products Standards on Finger-Joined Structural Lumber;

SPS 2-2003, Special Products Standards on Machine Stress-Rated Lumber.

SAE** PublicationSAE Handbook, 2004.

Truss Plate Institute of CanadaTPIC-1996, Truss Design Procedures and Specifications for Light Metal Plate Connected Wood Trusses.

*American National Standards Institute/American Society of Mechanical Engineers.†American Society for Testing and Materials.‡National Institute of Standards and Technology.§National Lumber Grades Authority.**Society of Automotive Engineers.



3. Objectives and Design Requirements

3.1 ObjectiveThe objective of the provisions in this Standard is the achievement of acceptable assurances that thestructure, when correctly designed and built, will be fit for the intended use.

3.2 Limit StatesThe structure or portion thereof is considered fit for use when the structure, its components, and itsconnections are designed such that the requirements of Clauses 3.3, 4.1.2, and 4.1.3 are satisfied.

3.3 Design Requirements

3.3.1 Structural AdequacyAll members shall be so framed, anchored, tied, and braced together as to provide the strength andrigidity necessary for the purpose for which they are designed. All structural members shall be ofadequate size and quality to carry all loads and other forces that can be reasonably expected to act uponthem during construction and use without exceeding the strength or serviceability limit states.

3.3.2 New or Special Systems of Design and ConstructionNew or special systems of design or construction of wood structures or structural elements not alreadycovered by this Standard may be used where such systems are based on analytical and engineeringprinciples, or reliable test data, or both, that demonstrate the safety and serviceability of the resultingstructure for the purpose intended.

3.3.3 Structural IntegrityThe general arrangement of the structural system and the interconnection of its members shall providepositive resistance to widespread collapse of the system due to local failure.

3.3.4 Basis of DesignDesign in accordance with this Standard is based on the assumption that(a) the specified loads are realistic in size, kind, and duration;(b) the wood product is normal for its species, kind, and grade;(c) consideration is given to service conditions, including possible deterioration of members andcorrosion of fastenings;(d) the temperature of the wood does not exceed 50EC, except for occasional exposures to 65EC;(e) the design is competent, fabrication and erection are good, grading and inspection are reliable, andmaintenance is normal; and(f) wood products are used as graded or manufactured for a designated end use.

3.3.5 Quality of WorkThe quality of work in fabrication, preparation, and installation of materials shall conform throughout toaccepted good practice.

3.3.6 Design Drawings

3.3.6.1Where design drawings are required they shall be drawn to a scale adequate to convey the requiredinformation. The drawings shall show a complete layout of the structure or portion thereof that is thesubject of the design, with members suitably designated and located, including dimensions and detaileddescriptions necessary for the preparation of shop and erection drawings. Governing heights, columncentres, and offsets shall be dimensioned.



3.3.6.2Design drawings shall designate the design standards used, as well as material or product standardsapplicable to the members and details depicted.

3.3.6.3When needed for the preparation of shop drawings, the governing loads, reactions, shears, moments,and axial forces to be resisted by all members and their connections shall be shown on drawings orsupplemental material, or both.

3.3.6.4If camber is required for beams, girders, or trusses, the magnitude of such camber shall be specified onthe design drawings.

4. General Design

) 4.1 Ultimate and Serviceability Limit States

4.1.1 Method of AnalysisThe load effect on all members and connections shall be determined in accordance with recognizedmethods of analysis generally based on assumptions of elastic behaviour.

) 4.1.2 Ultimate Limit StatesDesign for ultimate limit states shall include(a) establishing the value of the effect of the factored loads individually and with the load combinationsspecified in Clause 4.2; and(b) confirming by rational means that for each load effect in Item (a), the factored load effect does notexceed the corresponding factored resistance, as determined in accordance with the appropriate clausesof this Standard.

4.1.3 Serviceability Limit StatesDesign for serviceability limit states shall include

) (a) establishing the value of the effect of the specified loads individually and with the load combinationsspecified in Clause 4.2; and(b) confirming by rational means that for each load effect in Item (a), the structural effect falls within thelimits specified in the appropriate clauses of this Standard.

4.1.4 Resistance FactorsThe resistance factors, φ, are given in the appropriate sections of this Standard for all applicable limitstates for wood members and fastenings.

4.2 Specified Loads, Load Effects, and Load Combinations

) 4.2.1 BuildingsExcept as provided for in Clause 4.2.2, the specified loads, load effects, and combinations to beconsidered in the design of a building and its elements shall be those given in Clauses 4.2.3 and 4.2.4.Note: Specified loads, load effects, and combinations specified herein are in accordance with the provisions of theNational Building Code of Canada, 2005, its Structural Commentaries on Part 4, and the Canadian FoundationEngineering Manual.



4.2.2 Other StructuresWhere load requirements other than those in Clause 4.2.1 are specified, the appropriateness of theapplicable factored resistance in this Standard shall be considered.

) 4.2.3 Specified Loads

4.2.3.1 Loads to be ConsideredSpecified loads shall include the following wherever applicable, and minimum specified values of theseloads shall be increased to account for dynamic effects where applicable:(a) D — dead load due to weight of members; the weight of all materials of construction incorporatedinto the building to be supported permanently by the member, including permanent partitions andallowance for nonpermanent partitions; the weight of permanent equipment;(b) E — load due to earthquake, including the effect of the importance factors in Clause 4.2.3.2;(c) L — live load due to intended use and occupancy, including loads due to cranes and the pressure ofliquids in containers; (d) S — load due to snow, including ice and associated rain, and also including the effect of theimportance factors in Clause 4.2.3.2;(e) W — load due to wind, including the effect of the importance factors in Clause 4.2.3.2;(f) H — permanent load due to lateral earth pressure, including groundwater; (g) P — permanent effects caused by prestress; and(h) T — load due to contraction or expansion caused by temperature changes, shrinkage, moisturechanges, creep in component materials, movement due to differential settlement, or combinationsthereof.

4.2.3.2 Importance FactorsFor the purpose of determining the specified S, W, or E loads of Clause 4.2.3.1, importance factorsshall be applied in accordance with Table 4.2.3.2.Note: For further information on specified loads and importance factors, see the National Building Code ofCanada, 2005.

) Table 4.2.3.2 Importance Factors for Determining S, W, or E Loads

Importance Ultimate Serviceability Ultimate Serviceability Ultimate Serviceabilitycategory limit state limit state limit state limit state limit state limit state

Importance factors for Importance factors for Importance factors forsnow loads, I wind loads, I earthquake loads, IS W E

Low 0.8 0.9 0.8 0.75 1.0 N/A

Normal 1.0 0.9 1.0 0.75 1.0 N/A

High 1.15 0.9 1.15 0.75 1.3 N/A

Post-disaster 1.25 0.9 1.25 0.75 1.5 N/A

) 4.2.4 Load Combinations

) 4.2.4.1 Load Combinations for Ultimate Limit StatesThe effect of factored principal plus companion loads shall be determined in accordance with the loadcombinations in Table 4.2.4.1. The applicable combination shall be that which results in the mostunfavourable effect.



) Table 4.2.4.1 Load Combinations for Ultimate Limit States

Case Principal loads* Companion loads

1 1.4D

2 (1.25D† or 0.9D) + 1.5L‡ 0.5S§ or 0.4W

3 (1.25D† or 0.9D) + 1.5S 0.5L§** or 0.4W

4 (1.25D† or 0.9D) + 1.4W 0.5L** or 0.5S

5 1.0D + 1.0E 0.5L§** + 0.25S§

*Refer to the National Building Code of Canada, 2005, for loads due to lateralearth pressure (H), prestress (P), and imposed deformation (T).†Refer to the National Building Code of Canada, 2005, for a dead load (D) for soil.‡The principal load factor of 1.5 for a live load (L) may be reduced to 1.25 for liquidsin tanks.§Refer to the National Building Code of Canada, 2005, for loads on exterior areas.**The companion load factor of 0.5 for a live load (L) shall be increased to 1.0 forstorage occupancies, equipment areas, and service rooms.

) 4.2.4.2 Load Combinations for Serviceability Limit StatesThe effect of principal plus companion loads shall be determined in accordance with the loadcombinations in Table 4.2.4.2. The applicable combination shall be that which results in the mostunfavourable effect.

) Table 4.2.4.2 Load Combinations for Serviceability Limit States

Case Principal loads Companion loads

1 1.0D*

2 1.0D* + 1.0L 0.5S† or 0.4W

3 1.0D* + 1.0S 0.5L† or 0.4W

4 1.0D* + 1.0W 0.5L or 0.5S

*Dead loads include permanent loads due to lateral earth pressure(H) and prestress (P).†Refer to the National Building Code of Canada, 2005, for loadson exterior areas.

) 4.2.4.3 — Deleted

) 4.2.4.4 — Deleted

) 4.2.4.5 — Deleted

4.3 Conditions and Factors Affecting Resistance

) 4.3.1 GeneralSpecified strengths and capacities for materials and fastenings shall be multiplied by the modificationfactors in this clause and the appropriate materials or fastening clauses.Note: The basis for derivation of specified strengths for sawn lumber members is described in the Canadian WoodCouncil’s Standard Practice Relating Specified Strengths of Structural Members to Characteristic Structural Properties. The principles described therein have also been used to guide derivations for other products in this Standard.

' & $



4.3.2 Load Duration Factor, KD

4.3.2.1 Specified Strengths and CapacitiesThe specified strengths and capacities given in this Standard are based on the standard-term duration ofthe specified loads.

4.3.2.2 Load Duration FactorExcept as specified in Clause 4.3.2.3, the specified strengths and capacities shall be multiplied by a loadduration factor, K , in accordance with Table 4.3.2.2, but not exceeding 1.15.D

Table 4.3.2.2Load Duration Factor, KD

Duration of loading K Explanatory notesD

Short term 1.15 Short-term loading means that condition of loading where the durationof the specified loads is not expected to last more than 7 dayscontinuously or cumulatively throughout the life of the structure. Examples include wind loads, earthquake loads, falsework, andformwork, as well as impact loads.

Standard term 1.00 Standard term means that condition of loading where the duration ofspecified loads exceeds that of short-term loading, but is less thanpermanent loading. Examples include snow loads, live loads due to occupancy, wheel loadson bridges, and dead loads in combination with all of the above.

Permanent 0.65 Permanent duration means that condition of loading under which amember is subjected to more or less continuous specified load. Examples include dead loads or dead loads plus live loads of suchcharacter that they are imposed on the member for as long a period oftime as the dead loads themselves. Such loads include those usuallyoccurring in tanks or bins containing fluids or granular material, loads onretaining walls subjected to lateral pressure such as earth, and floor loadswhere the specified load may be expected to be continuously applied,such as those in buildings for storage of bulk materials. Loads due tofixed machinery should be considered to be permanent.

Note: Duration of load may require professional judgment by the designer. Explanatory notes in this tableprovide guidance to designers about the types of loads and load combinations for which each modification factorshould be applied.

) 4.3.2.3 Permanent Load FactorFor standard-term loads where D is greater than the specified standard-term load, P , the permanent loads

factor may be used, or the factor may be calculated as

whereD = specified dead loadP = specified standard-term load based on S and L loads acting alone or in combinations

= S, L, S + 0.5L, or 0.5S + L, where S is determined using an importance factor equal to 1.0.

4.3.2.4 Combined LoadsWhen the total specified load is made up of loads acting for different durations, the design shall be basedon the most severe combination. The appropriate load duration factor shall be taken into account foreach load combination.



4.3.3 Service Condition Factor, KSWhere materials or fastenings are used in service conditions other than dry, specified strengths andcapacities shall be multiplied by the service condition factor, K , in the appropriate materials or fasteningS

clauses.

4.3.4 Preservative and Fire-Retardant Treatment Factor, KT

4.3.4.1 GeneralExcept as permitted in Clause 4.3.4.4, specified strengths and capacities shall be multiplied by thetreatment factor, K , in the appropriate materials or fastenings clause.T

4.3.4.2 Preservative TreatmentWhen conditions conducive to decay or other deterioration are likely to occur in the case of permanentstructures, wood should be pressure-treated with preservative in accordance with the requirements of theCSA Standard O80 Series. If possible, all boring, grooving, cutting, and other fabrication should becompleted before treatment. Fabrication that is carried out after pressure treatment shall be treatedlocally in accordance with the CSA Standard O80 Series.

4.3.4.3 Untreated WoodUntreated wood in permanent structures shall not be in direct contact with masonry, concrete, or soilwhen moisture transfer can occur. Any method that eliminates transfer of moisture, e.g., a minimum of10 mm air space around a member in a wall, shall be considered adequate protection.

4.3.4.4 Fire-Retardant TreatmentWhere wood is impregnated with fire-retardant or other strength-reducing chemicals, K shall beT

determined in accordance with the results of appropriate tests or shall not exceed the value of KT

tabulated in the appropriate clause.

) 4.3.5 System Factor, KHSpecified strengths may be multiplied by a system factor, K , as specified in Clauses 5.4.4, 6.4.3, 13.2.4.4,H

and 13.4.4.4.Note: See Clause A4.3.5 for additional information on system factors.

) 4.3.6 Size Factor, KZWhere size influences the specified strengths of members, the specified strengths shall be multiplied bythe size factor, K , in accordance with Clauses 5.4.5, 6.5.6., 6.5.8, 6.5.9, 13.2.5.1, 13.4.4.5, and 13.4.4.6.ZNote: See the Canadian Wood Council’s Commentary.

4.3.7 Lateral Stability Factor, KLThe effect of width-to-depth ratios and of the degree of lateral support on the factored bending momentresistance is specified in Clauses 5.5.4.2 and 6.5.6.4.

4.3.8 Reduction in Cross-Section

4.3.8.1 Net SectionThe net section, obtained by deducting from the gross section the area of all material removed by boring,grooving, dapping, notching, or other means, shall be checked in calculating the strength capacity of amember.

4.3.8.2 LimitationIn no case shall the net section be less than 75% of the gross section.

')



) 4.4 Resistance to Seismic LoadsThe factored resistance required for seismic loading may be obtained by the use of shearwalls anddiaphragms (Clause 9). Where concentrically braced heavy timber space frames or moment-resistingwood space frames are used to provide seismic resistance, fastenings such as nails, bolts, lag screws, orglulam rivets as specified in Clause 10 shall be detailed to provide ductile connections.Note: Split rings and shear plates are not generally considered to provide ductile connections.

4.5 Serviceability Requirements

4.5.1 Modulus of ElasticityThe modulus of elasticity for stiffness calculations, E , shall be taken asS

E = E(K K )S SE T

whereE = specified modulus of elasticity, MPaK = service condition factorSE

K = treatment factorT

) 4.5.2 Elastic DeflectionThe elastic deflection of structural members under the load combinations for serviceability limit statesshall not exceed 1/180 of the span. For members having cambers equalling at least dead load deflection,the additional deflection due to live, snow, and wind loads shall not exceed 1/180 of the span. Deflection under the load combinations for serviceability limit states shall be limited to avoid damage tostructural elements or attached nonstructural elements.Note: See Clause A4.5.2 for additional information on deflection of a wood frame system under static loads.

) 4.5.3 Permanent DeformationStructural members that support permanent loads in excess of 50% of the load combinations forserviceability limit states shall be designed to limit permanent deformation. In lieu of a more accurateevaluation of acceptable deflection limits, an upper limit of 1/360 of the span shall be imposed on theelastic deflection due to permanent loads.

4.5.4 PondingRoof framing systems shall be investigated by rational analysis to ensure adequate performance underponding conditions unless (a) the roof surface is provided with sufficient slope toward points of free drainage to preventaccumulation of rain water; or(b) for a simply supported system subjected to a uniformly distributed load, the following condition issatisfied:

whereE) = sum of deflections due to this load, mm, of all the components of the system (decking, secondary

beams, primary beams, etc)w = total uniformly distributed load, kN/m2

) 4.5.5 VibrationSpecial consideration shall be given to structures subjected to vibration to ensure that such vibration isacceptable for the use of the structure.Note: See Clause A4.5.5 for information on floor vibration. Additional information can be found in the commentary onserviceability criteria for deflections and vibrations in the User’s Guide — NBC 2005 Structural Commentaries (Part 4).


January 2005 20A

5. Sawn Lumber

5.1 ScopeDesign tables, data, and methods specified in Clause 5 apply only to structural lumber complying withthe requirements of CSA Standard CAN/CSA-O141.

5.2 Materials

5.2.1 Identification of Lumber

5.2.1.1 GeneralDesign in accordance with this Standard is predicated on the use of lumber that is graded inaccordance with the NLGA Standard Grading Rules for Canadian Lumber and identified by the gradestamp of an association or independent grading agency in accordance with the provisions ofCSA Standard CAN/CSA-O141.Note: A list of approved agencies may be obtained from the Canadian Lumber Standards Accreditation Board.

5.2.1.2 Canadian LumberIn this Standard, Canadian species are designated according to species combinations given inTable 5.2.1.2, which reflects marketing practice. These combinations should be used for general designpurposes.Note: The designer is strongly advised to check availability of species, grade, and sizes before specifying.

5.2.1.3 US LumberFor US commercial species combinations graded in accordance with the National Grading Rule forDimension Lumber, the design data may be determined using the species combination equivalents inTable 5.2.1.3.


August 2001 21

Table 5.2.1.2Species Combinations

Species combinations Stamp identification Species included in the combination

Douglas Fir-Larch D Fir-L (N) Douglas Fir, Western Larch

Hem-Fir Hem-Fir (N) Pacific Coast Hemlock, Amabilis Fir

Spruce-Pine-Fir S-P-F Spruce (all species except Coast Sitka Spruce), Jack Pine, Lodgepole Pine, Balsam Fir, Alpine Fir

Northern Species North Species Any Canadian species graded in accordance withthe NLGA rules

Notes:(1) Names of species in this Table are standard commercial names. Additional information on botanical names andother common names is given in CSA Standard CAN/CSA-O141.(2) The NLGA Standard Grading Rules for Canadian Lumber contains many species designations not shown in thisTable. If the species can be identified, however, it may be possible to group it in one of the species combinations, forpurposes of assigning specified strengths.

Table 5.2.1.3Lumber Species Equivalents

US combination Equivalent Canadian combination

Douglas Fir-Larch Douglas Fir-Larch

Hem-Fir Hem-Fir

Southern Pine Spruce-Pine-Fir

Note: The NLGA Standard Grading Rule for Canadian Lumber incorporates theNational Grading Rules for Dimension Lumber, a uniform set of grade descriptions andother requirements for softwood dimension lumber that form a required part of allsoftwood lumber grading rules in the United States. Thus, all dimension lumberthroughout Canada and the United States is graded to uniform requirements.

5.2.2 Lumber Grades and Categories

5.2.2.1 Visually Stress-Graded LumberTable 5.2.2.1 lists categories, limiting dimensions, and structural grades for which design data areassigned in this Standard. These grades are specified in the NLGA Standard Grading Rules for CanadianLumber.


22 August 2001

Table 5.2.2.1Visual Grades and Their Dimensions

Grade categorySmaller dimension,mm

Larger dimension,mm Grades

Light Framing 38 to 89 38 to 89 Construction, Standard

Stud 38 to 89 38 or more Stud

StructuralLight Framing

38 to 89 38 to 89 Select StructuralNo. 1, No. 2, No. 3

StructuralJoists and Planks

38 to 89 114 or more Select StructuralNo. 1, No. 2, No. 3

Beam and Stringer 114 or more Exceeds smaller dimensionby more than 51

Select StructuralNo. 1, No. 2

Post and Timber 114 or more Exceeds smaller dimensionby 51 or less

Select StructuralNo. 1, No. 2

Plank Decking 38 to 89 140 or more Select, Commercial

5.2.2.2 Machine Stress-Rated (MSR) and Machine Evaluated Lumber(MEL)Design data specified in this Standard apply to lumber graded and grade-stamped in accordance withNLGA Special Product Standard SPS 2, and identified by the grade stamp of a grading agency accreditedfor grading by mechanical means.Note: A list of accredited agencies may be obtained from the Canadian Lumber Standards Accreditation Board.

5.2.3 Finger-Joined LumberDesign data specified in this Standard apply to finger-joined lumber that has been produced and grade-stamped in accordance with NLGA Special Product Standard SPS 1.

5.2.4 Remanufactured LumberDimension lumber and timbers that are resawn or otherwise remanufactured shall be regraded inaccordance with Clause 5.2.1.

5.2.5 Mixed GradesWhen mixed grades are used, the specified strength shall be that of the grade having the lowest value.

5.3 Specified Strengths

5.3.1 Visually Stress-Graded Lumber

5.3.1.1The specified strengths (MPa) for visually stress-graded lumber are tabulated as follows:(a) structural joist and plank, structural light framing, and stud grade categories of lumber inTable 5.3.1A;(b) light framing grades in Table 5.3.1B;(c) beam and stringer grade categories of lumber in Table 5.3.1C; and(d) post and timber grade categories of lumber in Table 5.3.1D.



5.3.1.2The specified strengths (MPa) for plank decking shall be derived from Table 5.3.1A using the followinggrade equivalents:

Decking grade Equivalent lumber grade

Select Select StructuralCommercial No. 2

5.3.2 Machine Stress-Rated and Machine Evaluated LumberThe specified strengths (MPa) for machine stress-rated lumber are given in Table 5.3.2. The specifiedstrengths (MPa) for machine evaluated lumber are given in Table 5.3.3. Specified strengths in shear arenot grade-dependent and shall be taken from Table 5.3.1A for the appropriate species.

) Table 5.3.1ASpecified Strengths and Modulus of Elasticity for Structural

Joist and Plank, Structural Light Framing, and StudGrade Categories of Lumber (MPa)

Species fibre, shear, to grain,to grain, to grain,identification Grade f f ff f E E

Bendingat Longi- TensionPerpen-extreme tudinal parallelParallel dicular

b v

Compression

t

Modulus ofelasticity

c cp 05

D Fir-L SS 16.5 19.0 10.6 12 500 8 500No. 1/No. 2 10.0 1.9 14.0 7.0 5.8 11 000 7 000No. 3/Stud 4.6 4.6 2.1 10 000 5 500

Hem-Fir SS 16.0 17.6 9.7 12 000 8 500No. 1/No. 2 11.0 1.6 14.8 4.6 6.2 11 000 7 500No. 3/Stud 7.0 7.0 3.2 10 000 6 000

S-P-F SS 16.5 14.5 8.6 10 500 7 500No. 1/No. 2 11.8 1.5 11.5 5.3 5.5 9 500 6 500No. 3/Stud 7.0 7.0 3.2 9 000 5 500

Northern SS 10.6 13.0 6.2 7 500 5 500No. 1/No. 2 7.6 1.3 10.4 3.5 4.0 7 000 5 000No. 3/Stud 4.5 4.5 2.0 6 500 4 000

Note: Tabulated values are based on the following standard conditions:(a) 286 mm larger dimension;(b) dry service conditions; and(c) standard-term duration of load.



) Table 5.3.1BSpecified Strengths and Modulus of Elasticity for Light Framing

Grades (MPa) Applicable to Sizes 38 by 38 mm to 89 by 89 mm

Species shear, to grain,to grain,identification Grade f ff E E

Bendingatextremefibre,fb

Longitudinal parallelParallel

v

Compression Tension

t


c

Perpendicularto grain,fcp 05

D Fir-L Const. 13.0 3.2 16.0 7.0 6.6 10 000 5 500

Stand. 7.3 13.1 3.7 9 000 5 000

Hem-Fir Const. 14.3 2.7 16.9 4.6 7.0 10 000 6 000

Stand. 8.0 13.9 3.9 9 000 5 500

S-P-F Const. 15.3 2.6 13.1 5.3 6.2 9 000 5 500

Stand. 8.6 10.8 3.5 8 000 5 000

Northern Const. 9.9 2.2 11.9 3.5 4.5 6 500 4 000

Stand. 5.5 9.8 2.5 6 000 3 500

Notes:(1) The size factor K for light framing grades shall be 1.00, except that K shall be calculated in accordance withZ ZcClause 5.5.6.2.2, and K shall be determined in accordance with Clause 5.5.7.5.zcp

(2) Tabulated values are based on the following standard conditions:(a) 89 mm width (except for compression properties);(b) dry service conditions; and(c) standard-term duration of load.



) Table 5.3.1CSpecified Strengths and Modulus of Elasticity

for Beam and Stringer Grades (MPa)

Speciesidentification Grade f f f f f E E

Bending Longi- TensionPerpen-at extreme tudinal parallel Modulus ofParallel dicularfibre,* shear, to grain, elasticityto grain, to grain,

Compression

b v c cp t 05

D Fir-L SS 19.5 13.2 10.0 12 000 8 000No. 1 15.8 1.5 11.0 7.0 7.0 12 000 8 000No. 2 9.0 7.2 3.3 9 500 6 000

Hem-Fir SS 14.5 10.8 7.4 10 000 7 000No. 1 11.7 1.2 9.0 4.6 5.2 10 000 7 000No. 2 6.7 5.9 2.4 8 000 5 500

S-P-F SS 13.6 9.5 7.0 8 500 6 000No. 1 11.0 1.2 7.9 5.3 4.9 8 500 6 000No. 2 6.3 5.2 2.3 6 500 4 500

Northern SS 12.8 7.2 6.5 8 000 5 500No. 1 10.8 1.0 6.0 3.5 4.6 8 000 5 500No. 2 5.9 3.9 2.2 6 000 4 000

*Specified strengths for beams and stringers are based on loads applied to the narrow face. When beams and stringersare subject to loads applied to the wide face, the specified strength for bending at the extreme fibre and the specifiedmodulus of elasticity shall be multiplied by the following factors:

f E or Eb 05

Select Structural 0.88 1.00No. 1 or No. 2 0.77 0.90

Notes:(1) Beams and stringers have a smaller dimension of at least 114 mm, with a larger dimension more than 51 mmgreater than the smaller dimension.(2) An approximate value for modulus of rigidity may be estimated at 0.065 times the modulus of elasticity.(3) With sawn members thicker than 89 mm that season slowly, care should be exercised to avoid overloading incompression before appreciable seasoning of the outer fibre has taken place; otherwise, compression strengths for wetservice conditions shall be used.(4) Beam and stringer grades listed in this table are not graded for continuity (see Clause 5.5.3).(5) Tabulated values are based on the following standard conditions:(a) 343 mm larger dimension for bending and shear, 292 mm larger dimension for tension and compression parallel tograin;(b) dry service conditions; and(c) standard-term duration of load.



) Table 5.3.1DSpecified Strengths and Modulus of Elasticity

for Post and Timber Grades (MPa)

Speciesidentification Grade f f f f f E E

Bendingat Longi- TensionPerpen-extreme tudinal parallel Modulus ofParallel dicularfibre, shear, to grain, elasticityto grain, to grain,

Compression

b v c cp t 05

D Fir-L SS 18.3 13.8 10.7 12 000 8 000No. 1 13.8 1.5 12.2 7.0 8.1 10 500 6 500No. 2 6.0 7.5 3.8 9 500 6 000

Hem-Fir SS 13.6 11.3 7.9 10 000 7 000No. 1 10.2 1.2 10.0 4.6 6.0 9 000 6 000No. 2 4.5 6.1 2.8 8 000 5 500

S-P-F SS 12.7 9.9 7.4 8 500 6 000No. 1 9.6 1.2 8.7 5.3 5.6 7 500 5 000No. 2 4.2 5.4 2.6 6 500 4 500

Northern SS 12.0 7.5 7.0 8 000 5 500No. 1 9.0 1.0 6.7 3.5 5.3 7 000 5 000No. 2 3.9 4.1 2.5 6 000 4 000

Notes:(1) Posts and timbers have a smaller dimension of at least 114 mm, with a larger dimension not more than 51 mmgreater than the smaller dimension.(2) Posts and timbers graded to beam and stringer rules may be assigned beam and stringer strength.(3) An approximate value for modulus of rigidity may be estimated at 0.065 times the modulus of elasticity.(4) With sawn members thicker than 89 mm that season slowly, care should be exercised to avoid overloading incompression before appreciable seasoning of the outer fibre has taken place; otherwise, compression strengths for wetservice conditions shall be used.(5) Tabulated values are based on the following standard conditions:(a) 343 mm larger dimension for bending and shear, 292 mm larger dimension for tension and compression parallel tograin;(b) dry service conditions; and(c) standard-term duration of load.



) Table 5.3.2Specified Strengths and Modulus of Elasticity for Machine

Machine Stress-Rated Grades 38 mm Thick by All Widths (MPa)

Grade f E 89 to 184 mm >184 mm† f f

Bendingat Modulusextreme of Parallel Perpendicularfibre, elasticity, to grain, to grain,*b

Tension parallelto grain, f Compressiont

c cp

1200F -1.2E 17.4 8 300 6.7 — 15.1 5.3b

1350F -1.3E 19.5 9 000 8.4 — 16.9 5.3b

1450F -1.3E 21.0 9 000 9.0 — 17.3 5.3b

1500F -1.4E 21.7 9 700 10.1 — 17.5 5.3b

1650F -1.5E 23.9 10 300 11.4 — 18.1 5.3b

1800F -1.6E 26.1 11 000 13.2 — 18.7 5.3b

1950F -1.7E 28.2 11 700 15.4 — 19.3 5.3b

2100F -1.8E 30.4 12 400 17.7 — 19.9 6.5b

2250F -1.9E 32.6 13 100 19.6 — 20.5 6.5b

2400F -2.0E 34.7 13 800 21.6 — 21.1 6.5b

2550F -2.1E 36.9 14 500 23.0 — 21.7 6.5b

2700F -2.2E 39.1 15 200 24.1 — 22.3 6.5b

2850F -2.3E 41.3 15 900 25.8 — 22.9 6.5b

3000F -2.4E 43.4 16 500 26.9 — 23.5 6.5b

The following MSR grades provide a modulus of elasticity with higher corresponding strengths. For these MSR grades,qualification and daily quality control for tensile strength are required.

1400F -1.2E 20.3 8 300 9.0 9.0 17.1 5.3b

1600F -1.4E 23.2 9 700 10.7 10.7 17.9 5.3b

1650F -1.3E 23.9 9 000 11.4 11.4 18.1 5.3b

1800F -1.5E 26.1 10 300 14.6 14.6 18.7 5.3b

2000F -1.6E 29.0 11 000 14.6 14.6 19.5 5.3b

2250F -1.7E 32.6 11 700 19.6 19.6 20.5 5.3b

2250F -1.8E 32.6 12 400 19.6 19.6 20.5 6.5b

2400F -1.8E 34.7 12 400 21.6 21.6 21.1 6.5b

*Compression perpendicular to grain values are for S-P-F MSR (all grades) and Hem-Fir MSR lumber with E grade of10 300 MPa or higher. For other species or grades, use corresponding values for visually stress-graded lumber taken fromTable 5.3.1A for the appropriate group.†The tension design values for narrow widths may be assigned to these sizes, provided the lumber is subject to theappropriate level of qualification and daily quality control testing for tension strength, as specified in NLGA SPS 2.Notes:(1) Tabulated values are based on standard-term duration of load and dry service conditions.(2) The size factor K for MSR lumber shall be 1.00, except that K is given in Table 5.4.5, K is determined inZ Zv Zcp

accordance with Clause 5.5.7.5, and K is calculated in accordance with Clause 5.5.6.2.2.Zc



Table 5.3.3Specified Strengths and Modulus of Elasticity for Machine

Evaluated Lumber Grades 38 mm Thick by All Widths (MPa)

Grade f E f f f

Bending at Tensionextreme Modulus of parallel Parallel Perpendicularfibre, elasticity, to grain, to grain, to grain,*b t

Compression

c cp

M-10 20.3 8 300 9.0 17.1 5.3M-11 22.4 10 300 9.5 17.7 5.3M-12 23.2 11 000 9.5 17.9 5.3M-13 23.2 9 700 10.7 17.9 5.3M-14 26.1 11 700 11.2 18.7 5.3M-15 26.1 10 300 12.3 18.7 5.3M-18 29.0 12 400 13.5 19.5 6.5M-19 29.0 11 000 14.6 19.5 5.3M-21 33.3 13 100 15.7 20.7 6.5M-22 34.0 11 700 16.8 20.9 5.3M-23 34.7 12 400 21.3 21.1 6.5M-24 39.1 13 100 20.2 22.3 6.5M-25 39.8 15 200 22.4 22.5 6.5M-26 40.6 13 800 20.2 22.7 6.5

*Compression perpendicular to grain values are for S-P-F MEL (all grades) and Hem-Fir MEL lumber with E grade of10 300 MPa or higher. For other species or grades, use corresponding values for visually stress-graded lumber taken fromTable 5.3.1A for the appropriate group.Notes:(1) Tabulated values are based on standard-term duration of load and dry service conditions.(2) The size factor K for MEL lumber shall be 1.00, except that K is given in Table 5.4.5, K is determined inZ Zv Zcp

accordance with Clause 5.5.7.5, and K is calculated in accordance with Clause 5.5.6.2.2.Zc

5.4 Modification Factors

5.4.1 Load Duration Factor, KDThe specified strength of lumber shall be multiplied by a load duration factor, K , as given inD

Clause 4.3.2.2.

5.4.2 Service Condition Factor, KSThe specified strength of lumber shall be multiplied by a service condition factor, K , as given inS

Table 5.4.2.

5.4.3 Treatment Factor, KT

5.4.3.1The specified strength of lumber shall be multiplied by a treatment factor, K , as given in Table 5.4.3.T

5.4.3.2For lumber treated with fire-retardant or other strength-reducing chemicals, strength and stiffnesscapacities shall be based on the documented results of tests that shall take into account the effects oftime, temperature, and moisture content. Test procedures shall meet the requirements of Clause 3.3.2.Note: The effects of fire retardant treatments can vary depending on manufacturing materials and processes. See theCanadian Wood Council’s Commentary for additional explanation.


August 2001 29

5.4.4 System Factor, KH

5.4.4.1 Case 1Specified strengths for sawn lumber members in a system consisting of three or more essentially parallelmembers spaced not more than 610 mm apart and so arranged that they mutually support the appliedload may be multiplied by the system factor for Case 1 given in Table 5.4.4.Note: Case 1 applies to systems of closely spaced structural components such as light-frame trusses, composite buildingcomponents, and glued-laminated timbers. Case 1 may also apply to some conventional joist and rafter systems wherethe framing details do not meet the requirements of Clause 5.4.4.2.

5.4.4.2 Case 2Specified strengths for sawn lumber used in a system of solid joists, rafters, or studs meeting therequirements of Clause 5.4.4.1 may be multiplied by the system factor for Case 2 given in Table 5.4.4,provided that the following additional conditions are met:(a) the joists, rafters, or studs are sheathed with plywood, waferboard, or OSB of minimum 9.5 mmthickness, or with 17 mm minimum thickness lumber in combination with panel covering such asunderlayment or with wood finish flooring; and(b) the sheathing or subfloor is attached to the members to provide a minimum stiffness equivalent tothat provided by 2 in common nails at 150 mm centres at edges of sheathing panels, and 300 mmcentres elsewhere.Note: Case 2 applies to systems such as conventional light-frame wood floor, roof, and wall systems using dimensionlumber framing members and minimum required sheathing and fastenings. Tabulated Case 2 system factors are to beapplied to single-member section properties and cannot be used in conjunction with augmented section properties basedon analysis of partial composite action between lumber and sheathing.

5.4.4.3For lumber in built-up beams consisting of two or more individual members of the same depth that arefastened or glued together so the beam will deflect as a unit, specified strengths may be multiplied bythe system factor, KH, given in Table 5.4.4.

5.4.5 Size Factor, KZ

5.4.5.1Some specified strengths of visually stress-graded lumber vary with member size and shall be multipliedby a size factor, KZ, in accordance with Table 5.4.5.Note: See Clauses 5.4.5.2 and 5.4.5.3 for exceptions.

5.4.5.2The size factor, KZ, for light framing grades shall be 1.00, except that KZc shall be calculated inaccordance with Clause 5.5.6.2.2, and KZcp may be determined in accordance with Clause 5.5.7.5.

5.4.5.3The size factor, KZ, for machine stress-rated lumber and machine evaluated lumber shall be 1.00, exceptthat KZv shall be as given in Table 5.4.5, KZc shall be calculated in accordance with Clause 5.5.6.2.2, andKZcp may be determined in accordance with Clause 5.5.7.5.


30 August 2001

Table 5.4.2Service Condition Factors, KS

KS PropertyDry serviceconditions

Wet service conditions: sawnlumber, piling, and poles ofleast dimension

89 mm or less Over 89 mm

KSB Bending at extreme fibre 1.00 0.84 1.00

KSv Longitudinal shear 1.00 0.96 1.00

KSc Compression parallel to grain 1.00 0.69 0.91

KScp Compression perpendicular to grain 1.00 0.67 0.67

KSt Tension parallel to grain 1.00 0.84 1.00

KSE Modulus of elasticity 1.00 0.94 1.00

Table 5.4.3Treatment Factor, KT

ProductDry serviceconditions

Wet serviceconditions

Untreated lumber 1.00 1.00

Preservative-treated, unincisedlumber 1.00 1.00

Preservative-treated, incised lumberof thickness 89 mm or less, for(a) modulus of elasticity(b) other properties

0.900.75

0.950.85

Fire-retardant-treated lumber See Clause 5.4.3.2 for effects of fire-retardant treatment.

Table 5.4.4System Factor, KH

For specified strength in Case 1*

Case 2†

Built-up beamsVisuallygraded MSR

BendingLongitudinal shearCompression parallel to grainTension parallel to grainAll other properties

1.101.101.101.101.00

1.401.401.10N/A1.00

1.201.201.10N/A1.00

1.101.101.001.001.00

*See Clause 5.4.4.1 for conditions applying to Case 1.†See Clause 5.4.4.2 for conditions applying to Case 2.N/A = not applicable


August 2001 31

Table 5.4.5Size Factor, KZ, for Visually Stress-Graded Lumber

Largerdimension(mm)

Bending and shearKZb, KZv

Tensionparallelto grainKZt

Compressionperpendicularto grainKZcp

Compressionparallel tograinKZc

All otherproperties

Smaller dimension (mm)

38 to 64 89 to 102114 ormore All All All All

38 64 89114140184 to 191235 to 241286 to 292337 to 343387 or larger

1.71.71.71.51.41.21.11.00.90.8

——1.71.61.51.31.21.11.00.9

———1.31.31.31.21.11.00.9

1.51.51.51.41.31.21.11.00.90.8

See Clause 5.5.7.5 Value computedusing formula inClause 5.5.6.2.2

1.01.01.01.01.01.01.01.01.01.0

5.5 Strength and Resistance

5.5.1 GeneralClause 5.5 contains design data and methods that apply to sawn lumber of rectangular cross-section.

5.5.2 Sizes

5.5.2.1Except as provided in Clause 5.5.2.2, the standard dry size rounded to the nearest millimetre (netdimension) of lumber shall be used.

5.5.2.2In conjunction with Tables 5.3.1C and 5.3.1D, green manufactured sizes may be used for all serviceconditions.Notes:(1) In developing specified strengths in this Standard, variables of moisture content and shrinkage, and theirrelationship to strength and stiffness, have been taken into account. Standard sizes and net dimensions of structurallumber and timbers are given in CSA Standard CAN/CSA-O141.(2) Sizes rounded to the nearest millimetre are given in Table A5.5.2.

5.5.3 ContinuityBeam and stringer grades shall not be designed for continuity in determining requirements for bendingresistance, unless regraded along the full length of the member. Continuity may be considered indeflection and shear calculations whether the lumber is regraded or not.Note: Beam and stringer grades listed in Table 5.3.1C are not graded for continuity.

5.5.4 Bending Moment Resistance

5.5.4.1 GeneralThe factored bending moment resistance, Mr, of sawn members shall be taken as

Mr = NFbSKZbKL


32 August 2001

Vr

NFv

2An

3KZv

Fr

NFfAK

N

whereN = 0.9Fb = fb(KDKHKSbKT)fb = specified strength in bending (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3), MPaKZb = size factor in bending (Clause 5.4.5)KL = lateral stability factor (Clause 5.5.4.2)

5.5.4.2 Lateral Stability Factor, KL

5.5.4.2.1The lateral stability factor, KL, may be taken as unity when lateral support is provided at points of bearingto prevent lateral displacement and rotation, provided that the maximum depth-to-width ratio of themember does not exceed the following values:

4:1 if no additional intermediate support is provided;5:1 if the member is held in line by purlins or tie rods;6.5:1 if the compressive edge is held in line by direct connection of decking or joists spaced not more

than 610 mm apart;7.5:1 if the compressive edge is held in line by direct connection of decking or joists spaced not more

than 610 mm apart and adequate bridging or blocking is installed at intervals not exceedingeight times the depth of the member; or

9:1 if both edges are held in line.

Alternatively, KL may be calculated in accordance with the requirements of Clause 6.5.6.4.

5.5.4.2.2For built-up beams consisting of two or more individual members of the same depth, the ratio inClause 6.5.6.3.1 may be based on the total width of the beam, provided that the individual membersare fastened together securely at intervals not exceeding four times the depth.

5.5.5 Shear Resistance

5.5.5.1 GeneralThe factored shear resistance, Vr, of sawn members shall be taken as

whereN = 0.9Fv = fv(KDKHKSvKT)fv = specified strength in shear (Clauses 5.3.1 and 5.3.2), MPaAn = net area of cross-section (Clause 4.3.8), mm2

KZv = size factor in shear (Clause 5.4.5)Note: For sawn members notched on the tension side at supports, see Clause 5.5.5.3.

5.5.5.2 Loads near SupportsIn the calculation of shear resistance the effect of all loads acting within a distance from a support equalto the depth of the member need not be taken into account.

5.5.5.3 Notches on the Tension Side at SupportsThe factored notch shear force resistance at a notch on the tension side at supports, Fr, shall be taken as


August 2001 33

KN

0.006d 1.61

α1 η2

1

α31

½

whereN = 0.9Ff = ff(KDKHKSfKT)ff = specified notch shear force resistance (Clause 5.5.5.5), MPa

= 0.50 for all sawn membersKSf = service factor

= 1.00 for dry service= 0.70 for wet service

A = gross cross-section area, mm2

KN = notch factor (Clause 5.5.5.4)Note: Notches or abrupt changes of section will produce stress concentrations and should be avoided.

5.5.5.4 Notch FactorThe notch factor for members of rectangular cross-sections shall be determined as follows:

whered = depth of cross-section, mm" = 1 – (dn/d)dn = depth of notch measured normal to the member axis in accordance with Figure 5.5.5.4, mm,

which must not exceed 0.25d0 = e/de = length of notch measured parallel to the member axis, mm, from the centre of the nearest

support to reentrant corner of notch (Figure 5.5.5.4). For a member notched over an endsupport, the length of support may be taken as the lesser of minimum required bearing length(Clause 5.5.7) or the actual bearing length. For a continuous member the length of supportequals the actual bearing length.

Note: Values of KN for selected combinations of " and 0 are given in Table 5.5.5.4.

5.5.5.5 Shear Force at NotchesIn the calculation of notch shear force resistance, the associated applied force is the factored shear forcein the member at the support. The shear force is calculated using the component of the force normal tothe member axis. Consideration of the notch shear force resistance concerns avoidance of fracture at areentrant corner of a notch and does not negate the need to ensure that the residual cross-section at anotch can resist the factored shear force.


34 August 2001

e

dn

e

dn

dn

e

Figure 5.5.5.4Determination of Length and Depth of Notch

Table 5.5.5.4Values of KN

0

"

0.75 0.80 0.85 0.90 0.95

0.150.200.250.300.350.400.450.500.600.700.800.901.001.201.401.601.802.00

17.216.816.415.915.414.914.313.812.711.810.910.1 9.36 8.15 7.20 6.42 5.79 5.26

19.919.519.018.518.017.416.816.215.013.912.811.911.1 9.70 8.57 7.66 6.91 6.29

23.723.322.822.221.520.920.219.518.116.815.614.513.511.810.5 9.39 8.48 7.72

29.929.428.828.127.326.525.724.823.121.520.018.717.415.313.612.111.010.0

43.542.842.041.039.938.837.636.434.031.729.627.625.822.720.218.116.414.9

Notes:(1) " = 1 – dn/d; 0 = e/d(2) Interpolation may be applied for intermediate values of " and 0.


August 2001 35

CC

effective length associated with width

member width

CC

effective length associated with depth

member depth

KC

1.0FcKZcC3

c

35E05KSEKT

1

5.5.6 Compressive Resistance Parallel to Grain

5.5.6.1 Effective LengthUnless noted otherwise, the effective length Le = KeL shall be used in determining the slenderness ratio ofcompression members. Recommended effective length factors, Ke, for compression members are givenin Table A5.5.6.1.

5.5.6.2 Simple Compression Members

5.5.6.2.1 Constant Rectangular Cross-SectionThe slenderness ratio, CC, of simple compression members of constant rectangular section shall notexceed 50 and shall be taken as the greater of

or

5.5.6.2.2 Factored Compressive Resistance Parallel to GrainThe factored compressive resistance parallel to grain, Pr, shall be taken as

Pr = NFCAKZcKC

whereN = 0.8FC = fc(KDKHKScKT)fc = specified strength in compression parallel to grain (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3), MPaKZc = 6.3 (dL)–0.13 # 1.3

whered = dimension in direction of buckling (depth or width), mmL = length associated with member dimension, mm

5.5.6.2.3 Slenderness Factor, KCThe slenderness factor, KC, shall be determined as follows:

whereE05 = 0.82E for MSR lumber

= 0.75E for MEL lumber= as specified in Tables 5.3.1A to 5.3.1D for visually graded lumber

5.5.6.3 Spaced Compression MembersSpaced compression members shall be designed in accordance with the requirements of Clause A5.5.6.3using the specified strengths and adjustment factors for sawn lumber.

5.5.6.4 Built-up Compression Members

5.5.6.4.1 GeneralBuilt-up rectangular compression members shall consist of two to five individual members of at least38 mm thickness joined with nails or bolts, or bolts and split ring connectors. The factored compressive


36 August 2001

resistance of built-up compression members may be evaluated in accordance with Clauses 5.5.6.4.2 to 5.5.6.4.4, provided that the minimum values of end distance, edge distance, and spacing for fasteningsconform to the appropriate requirements in Clause 10 and the maximum value of end distance does notexceed 1.2 times the minimum value. The factored compressive resistance of the built-up compressionmember may be taken as the greater of the values calculated according to Clause 5.5.6.4.2, 5.5.6.4.3, or5.5.6.4.4, or the combined factored resistance of the individual pieces taken as independent members.Note: Slenderness ratios are calculated according to Clause 5.5.6.2.1 using the overall dimensions of the compositemember or the dimensions of the individual pieces, as appropriate.

5.5.6.4.2 Nailed Built-up Compression MembersThe factored compressive resistance of a built-up compression member fastened together with nails orspikes may be taken as 60% of the compressive strength of a solid member of equivalent gross cross-sectional dimensions designed according to Clause 5.5.6.2, provided that the following requirements aresatisfied:(a) spacing of nails along the member length shall not exceed six times the thickness of the thinnestpiece, and spacing perpendicular to the member length shall not exceed 20 times the nail diameter;(b) all nails shall penetrate through at least 3/4 of the thickness of the last individual piece, and nailsshall be driven alternately from either face of the built-up member along the length; and(c) when the individual pieces of the built-up member are wider than three times their thickness, thereshall be at least two rows of nails across the member width.

5.5.6.4.3 Bolted Built-up Compression MembersThe factored compressive resistance of a built-up compression member fastened together by minimum1/4 in diameter bolts may be taken as 75% of the compressive strength of a solid member of equivalentgross cross-sectional dimensions designed according to Clause 5.5.6.2, provided that the followingrequirements are satisfied:(a) spacing of bolts along the member length shall not exceed six times the thickness of the thinnestpiece, and spacing perpendicular to the member length shall not exceed 10 times the bolt diameter; and(b) when the individual pieces of the built-up member are wider than three times their thickness, thereshall be at least two rows of bolts across the member width.

5.5.6.4.4 Split-Ring-Connected Built-up Compression MembersThe factored compressive resistance of a built-up compression member fastened together at intervals notexceeding six times the thickness of the thinnest piece by minimum 1/2 in diameter bolts and 2-1/2 insplit-ring connectors may be calculated as having 80% of the compressive strength of a solid member ofequivalent gross cross-sectional dimensions designed according to Clause 5.5.6.2.

5.5.6.4.5 Built-up Compression Members as Simple CompressionMembersExcept for spaced compression members, the factored compressive resistance of built-up compressionmembers not meeting the requirements of Clauses 5.5.6.4.1 to 5.5.6.4.4 shall be taken as the combinedfactored compressive strength of the individual pieces considered as independent members.

5.5.6.4.6 Strong Axis BucklingThe strength reduction factors given in Clauses 5.5.6.4.2 to 5.5.6.4.4 may be omitted for buckling in thestrong axis of the laminations.

5.5.6.5 Stud WallsWhen stud walls are adequately sheathed on at least one side, as in light frame construction, thedimension of the stud normal to the sheathing may be used in calculating the slenderness ratio.



5.5.6.6 Spliced Built-up Compressive Members

5.5.6.6.1Spliced nail-laminated built-up columns that are constructed in accordance with Figure 5.5.6.6 may bedesigned for axial loads and bending loads applied parallel to the wide face of the laminations inaccordance with Clauses 5.5.6.6.2 and 5.5.6.6.3, provided that the following additional conditions aremet:(a) the spliced columns shall consist of three members, with nails penetrating all three members;(b) the minimum overall splice length, L, shall be 1200 mm;(c) the spliced columns shall be braced by sheathing, or purlins spaced at a maximum of 600 mm oncentres in the direction perpendicular to the wide face of the laminations;(d) minimum lamination size shall be 38 mm thick by 140 mm wide; and(e) maximum lamination size shall be 38 mm thick by 184 mm wide.

5.5.6.6.2The factored bending resistance shall be determined using Clause 5.5.10 based on equivalent membersof the same size, grade, and species, using(a) 40% of the factored bending resistance of an unspliced built-up beam in the splice region, R; and(b) 100% of the factored bending resistance of an unspliced built-up beam outside of the spliceregion, R.

5.5.6.6.3The factored compressive resistance in the direction parallel to the wide face of the laminations shall bedetermined using Clause 5.5.6.2.2 based on an E value equal to 60% of the value for a simple05

compression member of the same species and grade.Note: Splicing of built-up members significantly reduces their stiffness and bending resistance, and should be avoidedwherever possible.

4

6

7

1 1

3

2

5

220 mm

L—2 >–

Legend:1. 3 members, 38 mm thick2. Treated wood portion, when

required 3. Untreated wood portion4. Splice length, L > 1200 mm5. Splice region, R = 1.5 L6. Nails: 4-1/2 inch common wire nail

hot-dip galvanized when used in treated wood; 6 per joint; 220 mm oc; 2 per row driven from alternate sides

7. Butt joints

–



) Figure 5.5.6.6Spliced Built-up Columns


August 2001 39

Ab

bLb1

Lb2

2, but 1.5b(L

b1)

5.5.7 Compressive Resistance Perpendicular to Grain

5.5.7.1 GeneralFactored bearing forces shall not exceed the factored compressive resistance perpendicular to graindetermined in accordance with the provisions of Clauses 5.5.7.2 and 5.5.7.3.

5.5.7.2 Effect of All Applied LoadsThe factored compressive resistance perpendicular to grain under the effect of all factored applied loadsshall be taken as Qr in the following formula:

Qr = NFcpAbKBKZcp

whereN = 0.8Fcp = fcp(KDKScpKT)fcp = specified strength in compression perpendicular to grain (Tables 5.3.1A to 5.3.1D, 5.3.2, and

5.3.3), MPaAb = bearing area, mm2

KB = length of bearing factor (Clause 5.5.7.6)KZcp = size factor for bearing (Clause 5.5.7.5)

5.5.7.3 Effect of Loads Applied near a SupportThe factored compressive resistance perpendicular to grain under the effect of only those loads appliedwithin a distance from the centre of the support equal to the depth of the member shall be taken as QrNin the following formula: QrN = (2/3)NFcpAbNKBKZcp

whereN = 0.8Fcp = fcp(KDKScpKT)AbN = average bearing area (see Clause 5.5.7.4)

5.5.7.4Where unequal bearing areas are used on opposite surfaces of a member, the average bearing area shallnot exceed the following:

whereb = average bearing width (perpendicular to grain), mmLb1 = lesser bearing length, mmLb2 = larger bearing length, mm

5.5.7.5 Size Factor for Bearing, KZcpWhen the width of a member (dimension perpendicular to the direction of the load) is greater than thedepth of the member (dimension parallel to the direction of the load), specified strength in compressionperpendicular to grain may be multiplied by a size factor for bearing, KZcp, in accordance withTable 5.5.7.5.


40 August 2001

Nr

PrQr

Prsin2θ Q

rcos2θ

Table 5.5.7.5Size Factor for Bearing, KZcp

Ratio of member width to member depth* KZcp

1.0 or less2.0 or more

1.001.15

*Interpolation applies for intermediate ratios.

5.5.7.6 Length of Bearing Factor, KBWhen lengths of bearing or diameters of washers are less than 150 mm, specified strengths incompression perpendicular to grain may be multiplied by a length of bearing factor, KB, in accordancewith Table 5.5.7.6, provided that(a) no part of the bearing area is less than 75 mm from the end of the members; and(b) bearing areas do not occur in positions of high bending stresses.

Table 5.5.7.6Length of Bearing Factor, KB

Bearing length (parallel to grain)or washer diameter (mm) Modification factor, KB

12.5 and less 25.0 38.0 50.0 75.0100.0150.0 or more

1.751.381.251.191.131.101.00

5.5.8 Compressive Resistance at an Angle to GrainThe factored compressive resistance at an angle to grain shall be taken as

wherePr = factored compressive resistance parallel to grain (Clause 5.5.6.2.2, assuming KC = 1.00), NQr = factored compressive resistance perpendicular to grain (Clause 5.5.7.2), N2 = angle between direction of grain and direction of load,E

5.5.9 Tensile Resistance Parallel to GrainThe factored tensile resistance, Tr, parallel to grain shall be taken as

Tr = NFtAnKZt

whereN = 0.9Ft = ft(KDKHKStKT)ft = specified strength in tension parallel to grain (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3), MPaAn = net area of cross-section (Clause 4.3.8), mm2 KZt = size factor in tension (Clause 5.4.5)


August 2001 41

Pf

Pr

Mf

Mr

1.0

Tf

Tr

Mf

Mr

1.0

5.5.10 Resistance to Combined Bending and Axial LoadMembers subject to combined bending and compressive or tensile axial loads shall be designed to satisfythe appropriate interaction equation:

or

wherePf = factored compressive axial loadPr = factored compressive load resistance parallel to grain calculated in accordance with the

requirements of Clause 5.5.6Mf = factored bending moment, taking into account end moments and amplified moments due to axial

loads in laterally loaded membersMr = factored bending moment resistance calculated in accordance with the requirements of

Clause 5.5.4Tf = factored tensile axial loadTr = factored tensile load resistance parallel to grain calculated in accordance with the requirements of

Clause 5.5.9

5.5.11 Decking

5.5.11.1 GeneralTo utilize continuity in the design of decking, the conditions specified in Clauses 5.5.11.2 to 5.5.11.5shall apply.

5.5.11.2 Plank Decking

5.5.11.2.1 Fastening RequirementsMaterial shall be 75 mm or more in width and shall be tongued and grooved or splined. Planks 38 mmor less in thickness shall be nailed to the supporting members with nails not shorter than twice thethickness of the plank and in no case less than 2-1/2 in. Planks thicker than 38 mm shall be toe-nailed tothe supporting members with one 5 in toe-nail and face-nailed with one or more nails not less than 6 inin length. Planks 140 mm or less in width shall be nailed with two nails to each support. Planks morethan 140 mm in width shall be nailed with three nails to each support.

5.5.11.2.2 Butt JointsIn bridges, each plank shall extend over at least one support. In roofs and floors, planks not extendingover at least one support in any span are permitted, provided that they are(a) double tongue-and-groove planks more than 38 mm in thickness;(b) flanked by planks that rest on both supports of that span; and(c) separated by at least six planks in that span, each of which extends over at least one support.

5.5.11.3 Nail Laminated Decking

5.5.11.3.1 Fastening RequirementsMaterial shall be 38 mm or more in thickness and 64 mm or more in width, and shall be laid on edgeand spiked together. Nails used to spike the laminations together shall be at least 4 in long for 38 mmthickness laminations and 6 in long for 64 mm thickness laminations. Decking 140 mm or less in depthshall be spiked together with a staggered single row of nails at intervals of not more than 450 mm in therow. One nail shall be placed not more than 100 mm from the end of each lamination. Decking more


42 August 2001

than 140 mm in depth shall be spiked together with a staggered double row of nails at intervals of notmore than 450 mm in each row. Two nails shall be placed not more than 100 mm from the end of eachlamination. Each lamination shall be toe-nailed to each support with not less than 4 in nails.

5.5.11.3.2 Butt JointsIn bridges, each lamination shall extend over at least one support. In roofs and floors, laminations notextending over at least one support in any span shall be flanked by laminations that rest on bothsupports of that span, and shall be separated by at least six laminations in that span, each of whichextends over at least one support.

5.5.11.4 Deflection CalculationsFor uniform design loads, decking deflections for the laying patterns described in Table 5.5.11.4 shall becalculated by the formulae given in Table 5.5.11.4. For other loading conditions or laying patterns,deflections shall be calculated by recognized engineering formulae.

5.5.11.5 BendingBending moments for plank decking laid in a controlled, random pattern, as described in Table 5.5.11.4,shall be calculated on the basis of simple span moments. For other deck patterns, bending momentsshall be calculated on the basis of recognized engineering formulae.

Table 5.5.11.4Laying Patterns and Deflection Formulae for Decking

Pattern Description Deflection formula*

Simple span All pieces bear on two supports only )1 = 5wR4 ______ 384ES3

Controlled random Decking continuous for three or more spans

End joints staggered in adjacent planks not lessthan 610 mm

Joints in same general line separated by at leasttwo intervening courses

End joints in first half of end spans avoided

)2 = 0.77)1

Requirements of Clause 5.5.11.2.2 or5.5.11.3.2 shall be met

Continuous over two spans All pieces bear on three supports )3 = 0.42)1

*whereª = deflection, mmw = uniformly distributed specified load, kN/m2

R = span, mmES = modulus of elasticity, MPa3 = moment of inertia of the decking, mm4 per m of width

5.5.12 Preserved Wood Foundations

5.5.12.1 GeneralAll lumber and plywood in preserved wood foundations shall be treated with a preservative inaccordance with CSA Standard O80.15, except where exempted from treatment by CSA StandardCAN/CSA-S406. The provisions for design of preserved wood foundations are predicated on the use of lumber andplywood identified by a certification mark on the material that confirms that treatment, where required,has been carried out by a plant certified under CSA Standard O322.Note: CSA Standard O322 outlines procedures for the certification of treatment plants and for the identification of wood


August 2001 43

materials pressure-treated for use in preserved wood foundations. Refer to Clause A5.5.12 for more details about wood wood foundations.

5.5.12.2 Wall FootingsIn the design of wall footings for preserved wood foundations, the specified strength in bendingperpendicular to grain for wood footing plates that are wider than the bottom plates shall not exceed1/3 the factored shear resistance. A granular layer, under footings, may be assumed capable ofdistributing the load transferred by the footing to the undisturbed soil at an angle of not more than 30Eto the vertical.

5.5.13 Sawn Lumber Design for Specific Truss ApplicationsNote: See also Clause A5.5.13.

5.5.13.1 ScopeDesign methods specified in Clause 5.5.13 apply only to fully triangulated metal-plate-connected woodroof trusses that meet the following conditions:(a) spacing not to exceed 610 mm;(b) clear span between inside face of supports not to exceed 12.20 m;(c) total truss length between outermost panel points not to exceed 18.0 m, with no single cantileverlength exceeding 25% of the adjacent clear span; and (d) top chord pitch not less than 2 in 12. Clause 5.5.13 does not apply to girder, bowstring, semi-circular, or attic trusses (which have non-triangulated sections), or to flat or floor trusses.Note: The provisions of Clause 5.5.13 are predicated on the determination of load effects on members and connectionsin accordance with recognized methods of analysis such as those given in TPIC Truss Design Procedures.

5.5.13.2 GeneralExcept as modified in Clauses 5.5.13.3 to 5.5.13.5, truss member design shall be in accordance with thesawn lumber provisions of Clauses 5.5.1 to 5.5.10. Metal connector plate design shall be in accordancewith Clause 10.8.

5.5.13.3 Compressive Resistance Parallel to Grain

5.5.13.3.1Unless otherwise required, the effective length, Le = Ke LP, shall be used in determining the slendernessratio for truss compression members, whereLe = effective length of truss compression memberKe = effective length factor for truss compression memberLP = actual length of member between adjacent panel pointsNote: Effective length factors for compression members and conditions under which these factors apply may be foundin TPIC Truss Design Procedures.

5.5.13.3.2A compression chord member containing a metal-plate-connected splice may be considered continuousfor a specific load case if the splice is located within ±10% of the panel length from an inflection point.

5.5.13.3.3The member length, L, used in Clause 5.5.6.2.2 to compute the factor KZc shall be the greater of thepanel length or one-half the chord length between pitch breaks.

5.5.13.4 Compressive Resistance Perpendicular to GrainFactored bearing forces shall not exceed the factored compressive resistance perpendicular to graindetermined in accordance with the provisions of Clauses 5.5.7.2 and 5.5.7.3. The requirements of Clause 5.5.7.3 may be met by providing adequate bearing reinforcement against


44 August 2001

Pf

Pr

2Mf

KMMr

1.0 orTf

Tr

Mf

Mr

1.0

1.31 0.12M1

M2

•LP

d

–1

61.3

1.0 <M1

M2

3.0

2.20 0.53M1

M2

0.64M1

M2

2

0.41M1

M2

3

•LP

d

–1

61.3

the effects of concentrated bearing loads acting near a support.Note: Bearing reinforcing details using light-gauge metal plates that conform to Clause 10.8.1 may be found in TPICTruss Design Procedures.

5.5.13.5 Resistance to Combined Bending and Axial LoadMembers subject to combined bending and compressive or tensile axial load shall be designed to satisfythe appropriate interaction equation:


requirements of Clauses 5.5.6 and 5.5.13.3Mf = factored bending moment. Unless mid-panel deflection of truss chords are limited to criteria such

as in TPIC Truss Design Procedures, moments shall be amplified to account for the effects of axialloads on laterally loaded members

KM = bending capacity modification factor as defined in Table 5.5.13.5Mr = factored bending moment resistance calculated in accordance with the requirements of

Clause 5.5.4Tf

= factored tensile axial loadTr = factored tensile load resistance parallel to grain calculated in accordance with the requirements of

Clause 5.5.9

Table 5.5.13.5Bending Capacity Modification Factors, KM,

for Specific Truss Applications

KM* Applicable condition

Compression chord members continuousover one or more panel points, andwhere

Compression chord members continuousover one or more panel points, andwhere

1.0M1

M2

1.0

1.67LP

d

1

61.3

All other compression chord members

*whereM1 = maximum bending moment between panel points, NCmmM2 = maximum of the two panel point bending moments, NCmmLP = actual length of the member between adjacent panel points, mmd = depth of the member between adjacent panel points, mmNote: The sign of the bending moments, M1 and M2, are retained in determining KM. The factored bending moment,Mf , used in Clause 5.5.13.5 is the larger of the absolute values of M1 and M2.



6. Glued-Laminated Timber (Glulam)

6.1 ScopeCharacteristic strengths, design data, and methods specified in Clause 6 apply only to glued-laminatedtimber manufactured in accordance with CSA Standard CAN/CSA-O122.

6.2 Materials

6.2.1 Stress GradesDesign in accordance with Clause 6 is based on the use of the stress grades of glued-laminated timbergiven in Table 6.2.1.Note: The National Building Code of Canada, Part 4, requires that glued-laminated timber be fabricated in plantsconforming to CSA Standard CAN/CSA-O177. A list of certified manufacturers may be obtained from the certifying agencyor agencies providing certification service.

Table 6.2.1Glued-Laminated Timber Stress Grades

Primary Spruce-Lodgepole Pine- Hem-Fir and Douglasapplication Douglas Fir-Larch Jack Pine Fir-Larch

Wood species

Bending 20f-E, 24f-E 20f-E 24f-Emembers 20f-EX, 24f-EX 20f-EX 24f-EX

Compression 16c-E 12c-Emembers

Tension members 18t-E 14t-E

) 6.2.2 Appearance Grades

6.2.2.1 GeneralExcept as provided for in Clause 6.2.2.2, appearance grades as defined in CSA Standard CAN/CSA-O122do not affect the specified strength.

6.2.2.2 Textured FinishesSome manufacturers offer a variety of textured finishes. Designers are advised to check the availability oftextured finishes before specifying. Such finishes may change the finished sizes and tolerances given in CSA Standard CAN/CSA-O122. Depending on the degree of texturing, it may be necessary for the designer to compensate for anyresulting reduction of cross-section and/or specified strength of the member.

6.3 Specified StrengthsThe specified strengths for glued-laminated timber are given in Table 6.3.



) Table 6.3Specified Strengths and Modulus of Elasticity

for Glued-Laminated Timber (MPa)

Douglas Fir-Larch

24f-E 24f-EX 20f-E 20f-EX 18t-E 16c-E

Bending moment (pos.) f 30.6 30.6 25.6 25.6 24.3 14.0b

Bending moment (neg.) f 23.0 30.6 19.2 25.6 24.3 14.0b

Longitudinal shear f 2.0 2.0 2.0 2.0 2.0 2.0v

Compression parallel f 30.2* 30.2* 30.2* 30.2* 30.2 30.2c

Compression parallel combined f 30.2* 30.2 30.2* 30.2 30.2 30.2with bending

cb

Compression perpendicular f— compression face bearing 7.0 7.0 7.0 7.0 7.0 7.0— tension face bearing 7.0 7.0 7.0 7.0 7.0 7.0

cp

Tension net section f 20.4* 20.4 20.4* 20.4 23.0 20.4(See Clause 6.5.11)

tn

Tension gross section f 15.3* 15.3 15.3* 15.3 17.9 15.3tg

Tension perpendicular to grain f 0.83 0.83 0.83 0.83 0.83 0.83tp

Modulus of elasticity E 13 100 13 100 12 400 12 400 13 800 12 400

Spruce-Lodgepole Pine- Hem-Fir andJack Pine Douglas Fir-Larch

20f-E 20f-EX 14t-E 12c-E 24f-E 24-EX

Bending moment (pos.) f 25.6 25.6 24.3 9.8 30.6 30.6b

Bending moment (neg.) f 19.2 25.6 24.3 9.8 23.0 30.6b

Longitudinal shear f 1.75 1.75 1.75 1.75 1.75 1.75v

Compression parallel f 25.2* 25.2* 25.2 25.2 — —c

Compression parallel f 25.2* 25.2 25.2 25.2 — —combined with bending

cb

Compression perpendicular f— compression face bearing 5.8 5.8 5.8 5.8 4.6 7.0— tension face bearing 5.8 5.8 5.8 5.8 7.0 7.0

cp

Tension net section f 17.0* 17.0 17.9 17.0 20.4* 20.4(See Clause 6.5.11)

tn

Tension gross section f 12.7* 12.7 13.4 12.7 15.3* 15.3tg

Tension perpendicular to grain f 0.51 0.51 0.51 0.51 0.83 0.83tp

Modulus of elasticity E 10 300 10 300 10 700 9700 13 100 13 100

*The use of this stress grade for this primary application is not recommended.Notes:(1) Designers are advised to check the availability of grades before specifying.(2) Tabulated values are based on the following standard conditions:(a) dry service conditions; and(b) standard term duration of load.


August 2001 47


6.4.1 Load Duration Factor, KDThe specified strength shall be multiplied by a load duration factor, KD, in accordance with Clause 4.3.2.

6.4.2 Service Condition Factor, KS

6.4.2.1Specified strengths for glued-laminated timber are tabulated for dry service conditions. For wet serviceconditions, tabulated values shall be multiplied by a service condition factor, KS, in accordance withTable 6.4.2.

6.4.2.2Where glued-laminated members that may be exposed to free moisture are adequately protected, anintermediate value of KS between 1.00 and that listed in Table 6.4.2 may be used.

6.4.3 System Factor, KHSpecified strengths for glued-laminated timber members in a system consisting of three or moreessentially parallel members spaced not more than 610 mm apart and so arranged that they mutuallysupport the applied load may be multiplied by a system factor, KH, equal to 1.00 for tension parallel tograin, and 1.10 for all other strength properties.

6.4.4 Treatment Factor, KTFor preservative treatment, the treatment factor for unincised glued-laminated timber may be taken asunity. For glued-laminated timber treated with fire-retardant or other potentially strength-reducingchemicals, strength and stiffness capacities shall be based on documented results of tests that shall takeinto account the effects of time, temperature, and moisture content. Test procedures shall meet therequirements of Clause 3.3.2. Treating of glued-laminated members with water-borne chemicals aftergluing shall not be permitted.

Table 6.4.2Service Condition Factors, KS

KS For specified strength in

Glued-laminated timber

Dry serviceconditions

Wet serviceconditions

KSb

KSv

KSc

KScp

KSt

KStp

KSE

Bending at extreme fibreLongitudinal shearCompression parallel to grainCompression perpendicular to grainTension parallel to grainTension perpendicular to grainModulus of elasticity

1.001.001.001.001.001.001.00

0.800.870.750.670.750.850.90


6.5.1 ScopeClause 6.5 contains design information and design formulae for glued-laminated timber members ofrectangular cross-section.


48 August 2001

6.5.2 OrientationDesign data for bending members specified in Clause 6.5 apply to horizontally laminated members, thewide faces of whose laminations are normal to the direction of load.

6.5.3 Vertically Glued-Laminated BeamsVertically glued-laminated beams, the narrow faces of whose laminations are normal to the direction ofload, shall be designed as a built-up system of sawn lumber members of No. 2 grade, in accordance withClause 5.4.4.3.

6.5.4 Net SectionThe net section, obtained by deducting from the gross cross-section the area of all material removed byboring, grooving, dapping, notching, or other means, shall be checked in calculating the strengthcapacity of a member. In no case shall the net section be less than 75% of the gross section.

6.5.5 SizesFor design purposes the actual dry size rounded to the nearest millimetre (net dimension) shall be usedfor both dry and wet service conditions.Note: Standard sizes rounded to the nearest millimetre are given in Clause A6.5.5.

6.5.6 Bending Moment Resistance

6.5.6.1 Members of Constant Cross-SectionThe factored bending moment resistance of glued-laminated timber members of constant cross-sectionshall be determined in accordance with Clause 6.5.6.5.

6.5.6.2 Curved and/or Double-Tapered MembersIn addition to the requirements of Clause 6.5.6.5, the factored bending moment resistance ofrectangular curved and/or tapered glued-laminated timber members shall not exceed the valuedetermined in accordance with Clause 6.5.6.6.

6.5.6.3 Lateral Stability Conditions

6.5.6.3.1For laterally unsupported glued-laminated timber bending members, the lateral stability factor, KL, maybe taken as unity, provided that the maximum depth-to-width ratio of the member does not exceed2.5:1. If the ratio is greater than 2.5:1, lateral support shall be provided at points of bearing to preventlateral displacement and rotation, and KL shall be determined in accordance with Clause 6.5.6.4.

6.5.6.3.2In the case of glued-laminated members of rectangular section subjected to combined bending and axialloads, the rules in Clause 5.5.4.2 may be applied.

6.5.6.3.3For two or more individual members of the same depth, the ratio in Clause 6.5.6.3.1 may be based onthe total width of the beam, provided that the individual members are fastened together securely atintervals not exceeding four times the depth.

6.5.6.4 Calculation of Lateral Stability Factor, KL

6.5.6.4.1 Unsupported Length, RuWhen no additional intermediate support is provided, the unsupported length, Ru, shall be the distancebetween points of bearing or the length of the cantilever. When intermediate support is provided by


August 2001 49

CB

Led

b 2

KL

11

3

CB

CK

4

purlins so connected that they prevent lateral displacement of the compressive edge of the bendingmember, the unsupported length shall be taken as the maximum purlin spacing, a.

6.5.6.4.2 Prevention of Lateral DisplacementWhen the compressive edge of the bending member is supported throughout its length so as to preventlateral displacement, the unsupported length may be taken as zero. For decking to provide suchsupport, it shall be fastened securely to the bending member and adjacent framing to provide a rigiddiaphragm.

6.5.6.4.3 Slenderness Ratio, CBThe slenderness ratio of a bending member shall not exceed 50 and shall be calculated as follows:

whereLe = effective length, mm, from Table 6.5.6.4.3

Table 6.5.6.4.3Effective Length, Le, for Bending Members

Intermediate support

Yes No

Beams Any loading Uniformly distributed load Concentrated load at centre Concentrated loads at 1/3 points Concentrated loads at 1/4 points Concentrated loads at 1/5 points Concentrated loads at 1/6 points Concentrated loads at 1/7 points Concentrated loads at 1/8 pointsCantilevers Any loading Uniformly distributed load Concentrated load at free end

1.92 a1.92 a1.11 a1.68 a1.54 a1.68 a1.73 a1.78 a1.84 a

1.92 Ru1.92 Ru1.61 Ru

1.92 Ru1.23 Ru1.69 Ru

Note: Ru and a are as defined in Clause 6.5.6.4.1.

6.5.6.4.4 Calculation of Lateral Stability Factor, KLThe lateral stability factor shall be determined as follows:(a) when CB does not exceed 10

KL = 1.0

(b) when CB is greater than 10, but does not exceed CK


50 August 2001

CK

0.97EKSEKT

Fb

KL

0.65EKSEKT

C2

BFbKX

KX

1 2000t

R

2

where

(c) when CB is greater than CK, but does not exceed 50

whereFb = fb(KDKHKSbKT)fb = specified strength in bending (Table 6.3), MPaKX = curvature factor (Clause 6.5.6.5.2)

6.5.6.5 Moment Resistance

6.5.6.5.1Except as provided for in Clauses 6.5.6.5.3 and 6.5.6.6, the factored bending moment resistance, Mr, ofglued-laminated timber members shall be taken as the lesser of Mr1 or Mr2 calculated from

Mr1 = φFbSKXKZbg and Mr2 = φFbSKXKL

whereφ = 0.9Fb = fb (KDKHKSbKT)fb = specified strength in bending (Table 6.3), MPaKL = lateral stability factor (Clause 6.5.6.4)KX = curvature factor (Clause 6.5.6.5.2)KZbg = 1.03 (BL)–0.18 #1.0

whereB = either the beam width (for single piece laminations) or the width of the widest piece (for

multiple piece laminations), mL = length of beam segment from point of zero moment to point of zero moment, m

Note: For beams with one or more points of inflection (i.e., multi-span beams and cantilevered beams), the size factoris calculated for each beam segment. The moment resistance for each beam segment as modified by the appropriatesize factor is then compared to the maximum factored moment within that segment.

6.5.6.5.2 Curvature Factor, KXFor the curved portion only of glued-laminated timber members, the specified strength in bending shallbe multiplied by the curvature factor.

wheret = lamination thickness, mmR = radius of curvature of the innermost lamination, mm

The minimum radius of curvature permitted for a given thickness of lamination shall conform to theprovisions set forth in CSA Standard CAN/CSA-O122. (See Table A6.5.5.)Note: KX = 1.0 for straight members and the straight portion of curved members.


August 2001 51

Mr

ΦFt p

2A

3RK

Ztp

6.5.6.5.3At the apex of curved double-tapered members (pitched cambered beams), the factored bendingmoment resistance, Mr, shall be taken as the value obtained by the formula in Clause 6.5.6.5.1 dividedby the factor [1 + 2.7 tan "], where " = slope of upper surface of member (roof slope) in degrees.

6.5.6.6 Radial ResistanceNotes:(1) The provisions of this clause apply to members of rectangular cross-section.(2) Radial stresses occur in curved and/or double-tapered glued-laminated members and may limit their factoredbending moment resistance.(3) When the bending moment tends to decrease curvature (increase the radius), the corresponding radial stress istension perpendicular to grain. When the bending moment tends to increase curvature (decrease the radius), thecorresponding radial stress is compression perpendicular to grain.

6.5.6.6.1The factored bending moment resistance as governed by tension perpendicular to grain, Mr, shall becalculated by the following formula, but shall not be greater than the value determined in accordancewith the requirements of Clauses 6.5.6.5.1 and 6.5.6.5.3. For double-tapered members, the additionalrequirement of Clause 6.5.6.6.2 shall also be satisfied.

whereN = 0.9Ftp = ftp(KDKHKStpKT)ftp = specified strength in tension perpendicular to grain (Table 6.3), MPaR = radius of curvature at centreline of member, mmKZtp = size factor in tension perpendicular to grain (Table 6.5.6.6.1)

Table 6.5.6.6.1Size Factor, KZtp, for Tension Perpendicular to Grain*

Member

Loading

Uniformly distributed All other

Constant depth, curved 24 ______ (AR$)0.2

20 ______ (AR$)0.2

Double-tapered, curved 35 ______ (AR$)0.2

22 ______ (AR$)0.2

Double-tapered, straight 36 ______ (Ad)0.2

23 ______ (Ad)0.2

*whereA = maximum cross-sectional area of member, mm2

R = radius of curvature at centreline of member, mm$ = enclosed angle in radians (1 radian = 57.3E)Notes:(1) For curved double-tapered members, $ is measured between points of tangency.(2) For curved uniform section members, $ is measured between the points where thefactored bending moment is 85% of the maximum factored bending moment.


52 August 2001

KR

A Bd

RC

d

R

21

6.5.6.6.2For double-tapered members subjected to radial tension perpendicular to grain, the following additionalrequirement shall be satisfied:

Mr = NFtpSKZtpKR

whereN = 0.9Ftp = ftp(KDKHKStpKT)ftp = specified strength in tension perpendicular to grain (Table 6.3), MPaS = section modulus at apex, mm3

KZtp = size factor in tension perpendicular to grain (Table 6.5.6.6.1)KR = radial stress factor (Clause 6.5.6.6.3)

6.5.6.6.3The radial stress factor, KR, shall be taken as

whereA,B,C = constants given in Table 6.5.6.6.3d = maximum depth at apex, mmR = radius of curvature at centreline of member, mm

Table 6.5.6.6.3Values of Constants for Determination

of Radial Stress in Double-TaperedCurved Members

Angle "*

Value of constant

A B C

2E30´5E7E30´10E15E20E25E30E

0.010.020.030.040.060.090.120.16

0.170.130.090.080.060.060.060.06

0.130.190.220.210.170.140.120.11

*See Figure 6.5.6.6.3.

R

90º

Lower face Tangent point

d

(a) Pitched Cambered Beam

R

90º

Inner face

Tangent point

d

(b) Arch Member

α

⇓

⇓

α



Figure 6.5.6.6.3Double-Tapered Member


6.5.7.1 General

6.5.7.1.1The provisions of Clause 6.5.7 apply to members of rectangular cross-section only.

' N

' &

' N $

' &

' &&



6.5.7.1.2In the calculation of shear resistance in Clause 6.5.7.2.1, the effect of all loads acting within a distancefrom a support equal to the depth of the member need not be taken into account.

6.5.7.2 Factored Shear Resistance — Case 1

) 6.5.7.2.1 GeneralThe factored shear resistance, V , of glued-laminated beams less than 2.0 m in volume, and ofr

3

glued-laminated members other than beams, shall be determined in accordance with the provisions ofClause 6.5.7.3, or shall be taken as

whereN = 0.9F = f (K K K K )v v D H Sv T

f = specified strength in shear (Table 6.3), MPav

A = gross cross-sectional area of member, mmg2

K = notch factor (Clause 6.5.7.2.2)NNotes:(1) Notches or abrupt changes of section will produce stress concentrations and should be avoided. The magnitude ofthese stress concentrations is reduced by gradual rather than abrupt changes of section.(2) Calculation of factored shear resistance in accordance with these requirements and this formula follows anapproximate method only, and may greatly underestimate the true factored shear resistance of glued-laminated members. For a more detailed and accurate calculation of shear resistance of glued-laminated members, refer to Clause 6.5.7.3.

6.5.7.2.2At the location of notches in rectangular members, the specified strength in shear shall be multiplied by anotch factor, K , determined as follows:N

(a) for notches at the tension side at supports

(b) for notches at the compression side

(i)

(ii)

where d = depth of notch, mm, which must not exceed 0.25dn

e = length of notch, mm, from inner edge of closest support to farthest edge of notch

) 6.5.7.3 Factored Shear Resistance — Case 2The factored shear resistance, V , of glued-laminated beams including those that exceed the maximumr

volume restriction of Clause 6.5.7.2.1 shall not be less than the sum of all factored loads, W , acting onf

the beam and shall be taken as

whereN = 0.9F = f (K K K K )v v D H Sv T

' R % %

''

''

'



f = specified strength in shear (Table 6.3), MPav

A = gross cross-sectional area of member, mmg2

K = notch factor (Clause 6.5.7.2.2)N

C = shear load coefficient (Clause 6.5.7.4)V

Z = beam volume, m3

6.5.7.4 Shear Load Coefficient, CVFor any load condition not shown in Tables 6.5.7.4A to 6.5.7.4F, the coefficient for simple span,continuous, or cantilevered beams of constant depth may be determined using the following procedure(the principle of superposition of loads does not apply):(a) Construct the shear force diagram for the beam. If the beam is under moving concentrated loads,construct the diagram of the maximum shear forces occurring along the full length of the beam withoutregard to sign convention. (Positive and negative maximum shear forces both show positive.)(b) Divide the total beam length, L, into n segments of variable lengths, R , such that within eacha

segment there are neither abrupt changes nor sign changes in the shear force.(c) For each segment determine

(i) V = factored shear force at beginning of segment, N;A

(ii) V = factored shear force at end of segment, N; andB

(iii) V = factored shear force at centre of segment, N;C

and calculate the factor G in accordance with the formula

(d) Determine the coefficient, C , in accordance with the following formulae:V

(i) for stationary loads

whereW = the total of all factored loads applied to the beam, Nf

(ii) for moving loads

whereW = the total of all factored moving loads and all factored distributed loads applied to the beam, Nf

Table 6.5.7.4AShear Load Coefficient, C , for Simple Span BeamsV

Number of equal loads equally andsymmetrically spaced 0.0 0.5 2.0 10.0 and over

r*

1 3.69 3.34 2.92 2.462 3.69 3.37 3.01 2.673 3.69 3.41 3.12 2.844 3.69 3.45 3.21 2.975 3.69 3.48 3.28 3.086 3.69 3.51 3.34 3.16

*

Table 6.5.7.4BShear Load Coefficient, CV, for Distributed Loads

0.0Type of loading 0.8 1.00.60.4

Pmin/Pmax

0.2

3.40 3.69 3.693.673.633.55

PmaxPmin

L

Table 6.5.7.4CShear Load Coefficient, CV, for Cantilevered Beams

L1/L2Beam type and loading 10.0 and over2.00.5

r*

0.0

0.050.100.200.30

2.732.081.751.62

4.063.072.532.31

5.645.194.363.83

3.914.134.554.88

0.050.100.200.30

4.863.723.172.97

7.135.424.494.10

6.196.726.906.31

4.134.585.506.40

total of concentrated loadstotal of uniform loads

*r =

L = L1 + L2

L2 L1

L = L2 + 2L1

L2 L1L1

Table 6.5.7.4DShear Load Coefficient, CV, for 2-Span Continuous Beams

L1/LLoading case† 10.0 and over2.00.5

r*

0.0

0.20.30.40.5

2.012.152.322.50

2.352.572.823.07

3.043.483.964.42

4.095.106.096.66


*r =

†Values shown correspond to the worst position for the concentrated loads

L1L

P




August 2001 57

Table 6.5.7.4EShear Load Coefficient, CV, for TaperedBeams — Uniformly Distributed Loads

L/d0*Beam case –0.080.050.10

m

0.20

102030

———

4.684.544.47

4.994.634.44

4.954.464.33

10152030

2.420.930.23—

0.00

3.973.693.58

3.973.773.693.58

–0.04

———

3.583.132.400.91

4.324.164.083.99

4.494.264.113.93

4.404.093.953.83

*To compute the ratio L/d0, L and d0 shall be in the same units.

m = (d1 – d0)————L

L

d0d1

m =2(d1 – d0)—————

L

L

d0

d1

Table 6.5.7.4FShear Load Coefficient, CV, for Moving Loads

Span, L(mm)Type of concentrated loads 3.01.5

r*

0.5

10 00020 00030 00040 000

1.901.901.901.90

2.122.122.122.12

2.652.652.652.65

10 00020 00030 00040 000

10.0

1.711.711.711.71

1.981.831.791.77

100.0

1.621.621.621.62

1.901.751.701.68

2.172.031.981.96

2.382.242.202.18

2.872.762.722.70

10 00020 00030 00040 000

4.172.862.402.21

4.202.802.322.13

4.112.992.572.40

4.053.132.752.59

3.933.393.143.03

10 00020 00030 00040 000

3.702.582.252.12

3.672.502.172.03

3.732.732.432.31

3.762.902.632.51

3.783.243.052.96

10 00020 00030 00040 000

3.722.862.502.29

3.702.792.422.21

3.743.002.672.47

3.763.132.842.66

3.783.403.203.08


*r =

PP

2400

L

P

PPP

4000 60006000

–3P

0.3P 0.8P P 0.8P

3600 7200

1200

6000

0.8P

0.44PPPPP

42007200

1200 1200


58 August 2001

6.5.8 Compressive Resistance Parallel to Grain

6.5.8.1 Effective Length, LeUnless noted otherwise, the effective length, Le = KeL, shall be used in determining the slenderness ratioof compression members. Recommended effective length factors, Ke, for compression members are given in Table A5.5.6.1.

6.5.8.2 Slenderness Ratio, CCThe slenderness ratio, CC, of simple compression members of constant rectangular section shall notexceed 50 and shall be taken as the greater of

CC


member width

or

CC


member depth

6.5.8.3 Variable Rectangular Cross-SectionTapered rectangular compression members shall be designed for an effective width or depth equal to theminimum width or depth plus 0.45 times the difference between the maximum and minimum widths ordepths. The factored compressive resistance determined in this manner shall not exceed the factoredresistance based on the minimum dimensions in conjunction with a slenderness factor KC = 1.00.

6.5.8.4 Factored Compressive Resistance Parallel to Grain

6.5.8.4.1Bending moments due to eccentrically applied axial loads shall be taken into account in accordance withClause 6.5.12.

6.5.8.4.2The factored compressive resistance parallel to grain, Pr, shall be taken as

Pr = NFcAKZcgKC

whereN = 0.8Fc = fc(KDKHKScKT)fc = specified strength in compression parallel to grain (Table 6.3), MPaKZcg = 0.68 (Z)–0.13 # 1.0

whereZ = member volume, m3

KC = slenderness factor (Clause 6.5.8.5)

6.5.8.5 Slenderness Factor, KCThe slenderness factor, KC, shall be determined as follows:

KC

1.0FcKZcgC3

c

35E05KSEKT

1

whereE05 = 0.87E


August 2001 59

Ab

bLb1

Lb2

2, but 1.5 bL

b1

6.5.8.6 Spaced Compression MembersSpaced compression members shall be designed in accordance with the requirements of ClauseA5.5.6.3, using the specified strengths and modification factors appropriate for glued-laminated timber.

6.5.8.7 Built-up Compression MembersBuilt-up compression members shall be designed in accordance with the requirements of Clause 5.5.6.4,using the specified strengths and adjustment factors appropriate for glued-laminated timber.

6.5.9 Compressive Resistance Perpendicular to Grain (Bearing)

6.5.9.1 GeneralFactored bearing forces shall not exceed the factored compressive resistance perpendicular to graindetermined in accordance with the provisions of Clauses 6.5.9.2 and 6.5.9.3.

6.5.9.2 Effect of All Applied LoadsThe factored compressive resistance perpendicular to grain under the effect of all applied loads shall betaken as Qr in the following formula:

Qr = NFcpAbKBKZcp

whereN = 0.8Fcp = fcp(KDKScpKT)fcp = specified strength in compression perpendicular to grain (Table 6.3), MPaAb = bearing area, mm2

KB = length of bearing factor (Clause 5.5.7.6)KZcp = size factor for bearing, where depth is thickness of lamination (Clause 5.5.7.5)

6.5.9.3 Effect of Loads Applied near a SupportThe factored compressive resistance perpendicular to grain under the effect of only those applied loadsacting within a distance from the centre of the support equal to the depth of the member shall be takenas QrN in the following formula:

QrN = (2/3)NFcpAbNKBKZcp

whereN = 0.8Fcp = fcp(KDKScpKT)fcp = f-E grade value from Table 6.3 for compression face bearing strength, MPaAbN = average bearing area (see Clause 6.5.9.4), mm2

6.5.9.4 Bearing Area on Opposite Faces of a MemberWhere unequal bearing areas are used on opposite surfaces of a member, the average bearing area shallnot exceed the following:

whereb = average bearing width (perpendicular to grain), mmLb1 = lesser bearing length, mmLb2 = larger bearing length, mm


60 August 2001

Pf

Pr

Mf

Mr

1.0 or

Tf

Tr

Mf

Mr

1.0

6.5.10 Compressive Resistance at an Angle to GrainThe factored compressive resistance at an angle to grain shall be calculated in accordance with therequirements of Clause 5.5.8, using the appropriate specified strengths and resistances for glued-laminated timber.

6.5.11 Tensile Resistance Parallel to GrainThe factored tensile resistance parallel to grain, Tr, shall be calculated as the lesser of

Tr = NFtnAn

or

Tr = NFtgAg

whereN = 0.9Ftn = ftn(KDKHKStKT)ftn = specified strength in tension parallel to grain at the net section (Table 6.3), MPaAn = net area of cross-section, mm2

Ftg = ftg(KDKHKStKT)ftg = specified strength in tension parallel to grain at the gross section (Table 6.3), MPaAg = gross area of cross-section, mm2

6.5.12 Resistance to Combined Bending and Axial LoadMembers subject to combined bending and compressive or tensile axial loads shall be designed to satisfythe appropriate interaction equation:


requirements of Clause 6.5.8.4 using Fcb = fcb(KDKHKScKT)Mf = factored bending moment, taking into account end moments and amplified moments due to axial


Clause 6.5.6.5.1Tf = factored tensile axial loadTr = factored tensile load resistance parallel to grain calculated in accordance with the requirements of

Clause 6.5.11

7. Structural Panels

7.1 ScopeDesign equations, data, and construction requirements specified in Clause 7 apply to the materialsspecified in Clause 7.2.


August 2001 61

Design equations and construction requirements for glued building components manufactured usingstructural panels are provided in Clause 8.

7.2 Materials

7.2.1 PlywoodThe provisions in Clauses 7.3 to 7.5 apply to standard constructions of regular grades of unsandedDouglas Fir plywood manufactured and identified in accordance with CSA Standard O121 and tostandard constructions of regular grades of unsanded Canadian Softwood plywood manufactured andidentified in accordance with CSA Standard O151.

7.2.2 OSB

7.2.2.1 Design-Rated OSBThe provisions in Clauses 7.3 to 7.5 apply to design-rated OSB Types 1, 2, and 3 that are qualified,certified for engineering uses, and identified in accordance with CSA Standard O452.0. Note: The designer is strongly advised to check availability before specifying.

7.2.2.2 Construction Sheathing OSBThe provisions in Clauses 7.3 to 7.5 also apply to OSB panels that are qualified and identified inaccordance with CSA Standard CAN/CSA-O325.0, which pertains to wood-based panel products,designed and manufactured for protected construction uses such as roof sheathing, wall sheathing, andfloor sheathing in light frame construction applications. Other tests and criteria may be required tocharacterize panels for special construction uses or other applications.Note: Construction Sheathing OSB is distinguished from other mat-formed panels by a mark showing the direction offace alignment. (See Clause A7.2.2.2 for additional information.)

7.2.3 Adhesives for Stress JointsAdhesives for stress joints for structural panels shall meet the requirements of CSA Standard O112.7.

7.3 Specified Capacities

7.3.1 PlywoodThe specified capacities for minimum veneer layup for each plywood thickness are given for Douglas Firplywood in Table 7.3A, and for Canadian Softwood plywood in Table 7.3B.Note: Information on thick panel layups is provided in Clause A7.3.1.

7.3.2 OSB

7.3.2.1The specified capacities for Type 1 (Standard) design-rated OSB are given in Table 7.3C.

7.3.2.2The specified capacities for Type 2 (Plus) panels shall be the capacities for the designated design ratingwith the Plus properties increased by the designated percentage shown on the panel (and obtainablefrom the manufacturer).

7.3.2.3The specified capacities for Type 3 (Proprietary) panels are not given in the Standard, but shall bedetermined in accordance with Clause 13.3 and listed on the Certificate of Conformance required byCSA Standard O452.0.


62 August 2001

7.3.2.4The specified capacities for Construction Sheathing OSB conforming to CSA Standard CAN/CSA-O325.0are given in Table 7.3D.

Table 7.3ASpecified Strength, Stiffness, and Rigidity Capacities for

Standard Constructions of Regular Grades of Unsanded Douglas Fir Plywood (DFP)

Nominalthickness,mm

No. ofplies

Bending,mp,N•mm/mm

Axialtension,tp,N/mm

Axialcompression,pp,N/mm

Shear-through-thickness,vp,N/mm

Planar shear

Bending,vpb,N/mm

Shear in-plane, vpf,MPa

Orientation of applied force relative to face grain

0E 90E 0E 90E 0E 90E 0E& 90E 0E 90E 0E 90E

7.5

9.5

12.512.5

15.515.5

18.518.518.5

20.520.520.5

22.522.5

25.525.525.525.5

28.528.528.528.5

31.531.531.531.531.5

3

3

4 5

4 5

5 6 7

5 6 7

7 8

7 8 910

8 91011

8 9101112

180

270

420 560

750 770

1300 9901100

120011001200

16001600

1900190020002000

2300230023002400

28002600260027002800

38

59

130 200

230 280

460 440 450

740 550 560

640 630

1000 850 850 910

1200100011001200

17001500130013001400

97

97

97130

160130

200160160

180170160

190190

220190220250

200220250250

240240250250250

23

28

55 71

72 71

110 71110

130 71110

110140

160160140140

200140140180

250190140180210

130

130

130170

200170

260210210

230220210

240240

280240280330

260280330330

320310330330330

40

50

96 79

130 79

120 79120

150 79120

130160

180180160160

230160160200

280210160200240

20

24

3030

4036

454343

474747

5252

58585858

65656565

7171717171

3.7

3.9

5.5 7.3

6.6 9.4

11.0 9.2 9.7

10.010.011.0

12.0 9.3

13.011.014.014.0

12.016.016.015.0

13.017.018.017.013.0

1.2

1.4

2.8 3.7

3.6 4.9

5.7 5.4 7.1

5.7 6.5 8.5

9.810.0

11.012.010.0 7.8

14.012.0 9.212.0

16.013.011.014.014.0

0.72

0.55

0.550.72

0.550.72

0.720.550.72

0.550.550.72

0.720.55

0.720.550.720.72

0.550.720.720.72

0.550.720.720.720.55

0.72

0.72

0.720.72

0.720.72

0.720.550.72

0.550.550.72

0.720.72

0.720.720.720.55

0.720.720.550.72

0.720.720.550.720.72

(Continued)


August 2001 63

Table 7.3A (Concluded)

Nominalthickness,mm

No.ofplies

Bending stiffness,Bb = E3,N•mm2/mm

Axial stiffness(in tension orcompression),Ba = EA,N/mm

Shear-through-thicknessrigidity,Bv,N/mm


0E 90E 0E 90E 0E& 90E

7.5

9.5

12.512.5

15.515.5

18.518.518.5

20.520.520.5

22.522.5

25.525.525.525.5

28.528.528.528.5

31.531.531.531.531.5

3

3

4 5

4 5

5 6 7

5 6 7

7 8

7 8 910

8 91011

8 9101112

440 000

840 000

1 700 000 1 700 000

3 800 000 3 000 000

6 000 000 4 600 000 4 900 000

6 300 000 5 900 000 6 200 000

8 800 000 9 100 000

12 000 00012 000 00013 000 00013 000 000

16 000 00016 000 00017 000 00017 000 000

22 000 00021 000 00021 000 00022 000 00022 000 000

17 000

33 000

190 000 350 000

430 000 630 000

1 300 000 1 300 000 1 400 000

2 600 000 1 900 000 2 000 000

2 500 000 2 500 000

4 800 000 4 100 000 4 100 000 4 400 000

7 000 000 5 700 000 6 100 000 6 400 000

11 000 000 9 400 000 8 200 000 8 500 000 9 000 000

70 000

70 000 70 000 94 000

110 000 94 000

140 000120 000120 000

130 000130 000120 000

130 000130 000

160 000130 000160 000180 000

140 000160 000180 000180 000

180 000170 000180 000180 000180 000

24 000

30 000

57 000 47 000

75 000 47 000

73 000 47 000 71 000

89 000 47 000 71 000

75 000 95 000

110 000110 000 95 000 95 000

140 000 95 000 95 000120 000

170 000120 000 95 000120 000140 000

4 600

5 500

6 900 6 900

9 100 8 400

10 000 9 800 9 800

11 00011 00011 000

12 00012 000

13 00013 00013 00013 000

15 00015 00015 00015 000

16 00016 00016 00016 00016 000

Notes:(1) For specified stiffness in bending on edge, use axial stiffness values.(2) Tabulated values are based on dry service conditions and standard-term duration of load.(3) Specified strength in bearing (normal to plane of panel) qp = 4.5 MPa.


64 August 2001

Table 7.3BSpecified Strength, Stiffness, and Rigidity Capacities for Standard Constructions of Regular Grades of Unsanded

Canadian Softwood Plywood (CSP)

Nominalthickness,mm

No.ofplies





Planar shear

Bending,vpb,N/mm



0E 90E 0E 90E 0E 90E 0E& 90E 0E 90E 0E 90E

7.5

9.5

12.512.5

15.515.5

18.518.518.5

20.520.520.5

22.522.5

25.525.525.525.5

28.528.528.528.5

31.531.531.531.531.5

3

3

4 5

4 5

5 6 7

5 6 7

7 8

7 8 910

8 91011

8 9101112

160

250

420 380

670 520

880 790 740

840 780 840

11001100

1300140014001500

1600160017001800

20001900190020002100

38

59

130 200

230 280

460 440 450

740 550 560

640 630

1000 850 850 910

1200100011001200

17001500130013001400

71

71

89110

110110

160160140

150150140

160160

190160200230

170200230230

220220230230230

23

28

55 71

72 71

110 71110

130 71110

110140

160160140140

200140140180

250190140180210

79

79

99120

130120

180180160

170170160

180180

210180220260

200220260260

250250260260260

40

50

96 79

130 79

120 79120

150 79120

130160

180180160160

230160160200

280210160200240

18

23

3030

3838

464646

515151

5656

63636363

71717171

7878787878

3.7

3.9

5.5 7.3

6.6 9.4

11.012.0 9.7

10.010.011.0

12.0 9.3

13.011.014.014.0

12.016.016.015.0

13.017.018.017.013.0

1.2

1.4

2.8 3.7

3.6 4.9

5.7 5.4 7.1

5.7 6.5 8.5

9.810.0

11.012.010.0 7.8

14.012.0 9.212.0

16.013.011.014.014.0

0.72

0.55

0.550.72

0.550.72

0.720.720.72

0.550.550.72

0.720.55

0.720.550.720.72

0.550.720.720.72

0.550.720.720.720.55

0.72

0.72

0.720.72

0.720.72

0.720.550.72

0.550.550.72

0.720.72

0.720.720.720.55

0.720.720.550.72

0.720.720.550.720.72

(Continued)


August 2001 65

Table 7.3B (Concluded)

Nominalthickness,mm

No.ofplies





0E 90E 0E 90E 0E& 90E

7.5

9.5

12.512.5

15.515.5

18.518.518.5

20.520.520.5

22.522.5

25.525.525.525.5

28.528.528.528.5

31.531.531.531.531.5

3

3

4 5

4 5

5 6 7

5 6 7

7 8

7 8 910

8 91011

8 9101112

300 000

570 000

1 300 000 1 200 000

2 600 000 2 000 000

4 100 000 3 600 000 3 400 000

4 300 000 4 000 000 4 300 000

6 100 000 6 400 000

8 600 000 8 700 000 9 000 000 9 400 000

12 000 00012 000 00012 000 00013 000 000

16 000 00015 000 00015 000 00016 000 00017 000 000

17 000

33 000

190 000 350 000

430 000 630 000

1 300 000 1 300 000 1 400 000

2 600 000 1 900 000 2 000 000

2 500 000 2 500 000

4 800 000 4 100 000 4 100 000 4 400 000

7 000 000 5 700 000 6 100 000 6 400 000

11 000 000 9 400 000 8 200 000 8 500 000 9 000 000

47 000

47 000

59 000 71 000

76 000 71 000

110 000110 000 95 000

100 000100 000 95 000

110 000110 000

130 000110 000130 000150 000

120 000130 000150 000150 000

150 000150 000150 000150 000150 000

24 000

30 000

57 000 47 000

75 000 47 000

73 000 47 000 71 000

89 000 47 000 71 000

75 000 95 000

110 000110 000 95 000 95 000

140 000 95 000 95 000120 000

170 000120 000 95 000120 000140 000

3 400

4 300

5 700 5 700

7 100 7 100

8 600 8 600 8 600

9 500 9 500 9 500

10 00010 000

12 00012 00012 00012 000

13 00013 00013 00013 000

15 00015 00015 00015 00015 000

Notes: (1) For specified stiffness in bending on edge, use axial stiffness values. (2) Tabulated values are based on dry service conditions and standard-term duration of load. (3) Specified strength in bearing (normal to plane of panel) qp = 4.5 MPa.


66 August 2001

Table 7.3CSpecified Strength, Stiffness, and Rigidity Capacities

for Type 1 (Standard) Design-Rated OSB*

Nominalthickness,mm

Ratinggrade

Planar shear

Bending, mp,N•mm/mm




Bending,vpb,N/mm


Capacities relative to major axis*†

0E 90E 0E 90E 0E 90E 0E& 90E 0E& 90E 0E& 90E

9.5 9.5 9.5

11.011.011.0

12.512.512.5

15.515.515.5

18.518.518.5

22.022.022.0

28.528.528.5

ABC

ABC

ABC

ABC

ABC

ABC

ABC

290 240 190

390 320 260

500 420 330

770 640 510

1100 910 720

160013001000

260022001700

90 90 90

120120120

160160160

240240240

340340340

480480480

810810810

79 63 47

91 73 55

100 83 62

130100 77

150120 92

180150110

240190140

38 38 38

44 44 44

50 50 50

62 62 62

74 74 74

88 88 88

110110110

79 63 47

91 73 55

100 83 62

130100 77

150120 92

180150110

240190140

38 38 38

44 44 44

50 50 50

62 62 62

74 74 74

88 88 88

110110110

303030

353535

404040

505050

595959

707070

919191

4.1 4.1 4.1

4.7 4.7 4.7

5.3 5.3 5.3

6.6 6.6 6.6

7.9 7.9 7.9

9.4 9.4 9.4

12.012.012.0

0.640.640.64

0.640.640.64

0.640.640.64

0.640.640.64

0.640.640.64

0.640.640.64

0.640.640.64

(Continued)



Table 7.3C (Concluded)

Nominalthickness, Ratingmm grade 0E 90E 0E 90E 0E& 90E

Bending stiffness, or compression), rigidity,B = E3, B = EA, B ,b

N•mm /mm N/mm N/mm2

Axial stiffness (in tension thickness

a

Shear-through-

v


9.5 A 590 000 170 000 46 000 19 000 9 500 9.5 B 490 000 170 000 39 000 19 000 9 500 9.5 C 390 000 170 000 33 000 19 000 9 500

11.0 A 920 000 270 000 53 000 22 000 11 00011.0 B 760 000 270 000 46 000 22 000 11 00011.0 C 610 000 270 000 38 000 22 000 11 000

12.5 A 1 300 000 390 000 60 000 25 000 12 00012.5 B 1 100 000 390 000 52 000 25 000 12 00012.5 C 900 000 390 000 43 000 25 000 12 000

15.5 A 2 600 000 740 000 75 000 31 000 15 00015.5 B 2 100 000 740 000 64 000 31 000 15 00015.5 C 1 700 000 740 000 53 000 31 000 15 000

18.5 A 4 400 000 1 300 000 89 000 37 000 18 00018.5 B 3 600 000 1 300 000 77 000 37 000 18 00018.5 C 2 900 000 1 300 000 64 000 37 000 18 000

22.0 A 7 300 000 2 100 000 110 000 44 000 22 00022.0 B 6 100 000 2 100 000 91 000 44 000 22 00022.0 C 4 900 000 2 100 000 76 000 44 000 22 000

28.5 A 16 000 000 4 600 000 140 000 57 000 28 00028.5 B 13 000 000 4 600 000 120 000 57 000 28 00028.5 C 11 000 000 4 600 000 98 000 57 000 28 000

*For Type 2 Design-Rated OSB panels, tabulated specified capacities are increased by a percentage(see CSA Standard O452.0). For Type 3 Design-Rated OSB panels, specified capacities are proprietary(see Clause 13.3). †Orientation of applied force relative to panel's long direction.Notes:(1) For specified stiffness in bending on edge, use axial stiffness values.(2) Tabulated values are based on dry service conditions and standard-term duration of load.(3) Specified strength in bearing (normal to plane of panel) q = 4.2 MPa.p



) Table 7.3DSpecified Strength, Stiffness, and Rigidity Capacities for

Construction Sheathing OSB

Panel Minimummark nominal(CSA thickness,*O325) mm 0E 90E 0E 90E 0E 90E 0E& 90E 0E 90E 0E 90E

Bending, tension, compression, thickness, Bending, in-plane,m , t , p , v , v , v ,p

N•mm/mm N/mm N/mm N/mm N/mm MPa

Axial Axial through- Shear

p p

Shear-

p

Planarshear

pb pf

Capacities relative to major axis†

2R24 9.5 180 57 53 18 62 54 42 3.8 2.4 0.60 0.381R24/2F16 11.0 240 68 60 30 71 54 46 4.4 2.4 0.60 0.332R32/2F16 12.0 270 100 65 38 77 67 50 4.8 3.0 0.60 0.382R40/2F20 15.0 460 160 67 48 92 87 55 6.1 3.8 0.61 0.382R48/2F24 18.0 630 240 92 59 110 94 60 7.8 4.4 0.65 0.37

1F16 15.0 310 100 60 43 87 78 47 5.2 3.3 0.52 0.331F20 15.0 360 150 67 48 92 87 54 6.1 3.9 0.61 0.391F24 18.0 480 230 77 59 110 94 59 7.8 4.5 0.65 0.371F32 22.0 640 400 92 75 140 130 64 9.2 6.4 0.63 0.441F48 28.5 1 200 720 130 110 180 150 85 14.0 10.0 0.73 0.55

(Continued)


August 2001 69

Table 7.3D (Concluded)

Panelmark (CSAO325)

Minimumnominalthickness,*mm





0E 90E 0E 90E 0E & 90E

2R241R24/2F162R32/2F162R40/2F202R48/2F24

1F161F201F241F321F48

9.511.012.015.018.0

15.015.018.022.028.5

560 000 730 000 1 100 000 2 100 000 3 800 000

1 400 000 2 000 000 2 800 000 6 100 00011 000 000

100 000 140 000 220 000 500 000 820 000

300 000 360 000 720 0002 100 0004 400 000

33 00038 00043 00053 00064 000

53 00053 00064 00076 00098 000

19 00022 00025 00031 00037 000

31 00031 00037 00044 00051 000

10 00011 00011 00012 00013 000

11 00011 00012 00015 00020 000

*The minimum nominal thickness shown on the panel mark can be 0.5 mm less than the values shown here.†Orientation of applied force relative to panel’s long direction.Notes:(1) For specified stiffness in bending on edge, use axial stiffness values.(2) Tabulated values are based on dry service conditions and standard-term duration of load.(3) Specified strength in bearing (normal to plane of panel) qp = 4.2 MPa.(4) Design values do not apply to panels marked W only.


70 August 2001



7.4.1.1Except as detailed in Clause 7.4.1.2, the specified strength capacity values for structural panels shall bemultiplied by a load duration factor, KD, as given in Table 4.3.2.2.

7.4.1.2For OSB used in structures subject to permanent loads in excess of 50% of design capacity, protectedfrom direct exposure to moisture, but exposed to intermittent high temperature and/or humidityconditions, the load duration factor shall be 0.45.

7.4.2 Service Condition Factor, KSThe specified strength capacity values for structural panels shall be multiplied by a service conditionfactor, KS, as given in Table 7.4.2.Note: OSB is specified for use under dry service conditions only.

Table 7.4.2Service Condition Factor, KS

Property to be modified

Plywood OSB

Service conditions

Dry Wet Dry

Specified strength capacitySpecified stiffness and rigidity capacities

1.0

1.0

0.80

0.85

1.0

1.0

7.4.3 Treatment Factor, KTFor preservative-treated plywood, KT = 1.0. For other preservative-treated structural panels and structuralpanels treated with fire-retardant or other potentially strength-reducing chemicals, strength and stiffnesscapacities shall be based on the documented results of tests that shall take into account the effects oftime, temperature, and moisture content. Test procedures and data shall meet the requirements ofClause 3.3.2.Note: See the Canadian Wood Council’s Commentary for additional explanation.

7.4.4 Stress Joint Factor, XJ

7.4.4.1 Scarf JointsWhere scarf joints transmit forces from one panel to another, the specified strength capacity shall bemultiplied by a stress joint factor, XJ, as given in Table 7.4.4.1. Construction requirements for scarf jointsare given in Clause 8.4.3.

© Canadian Standards Associatio n Engineering Design in Wood

August 2001 71

Table 7.4.4.1Stress Joint Factor, XJ, for Scarf Joints

Panel type Slope of scarf Tension, bending Compression Shear

Plywood 1 in 121 in 101 in 81 in 5

0.850.800.750.60

1.001.001.001.00

1.001.001.00—

OSB 1 in 61 in 51 in 4

0.800.700.60

0.800.700.60

0.800.700.60

7.4.4.2 Butt JointsWhere structural panels are used as glued splice plates in butt joints to transmit forces from one panel toanother or from one lumber piece to another, the specified strength of splice plates shall be multipliedby a stress joint factor, XJ, as given in Table 7.4.4.2. Construction requirements for butt joints are givenin Clause 8.4.4.

Table 7.4.4.2Stress Joint Factor, XJ, for Butt Joints

Main/sidemember

Nominalthicknessof panelspliceplate, mm

One side Both sides

Min.length ofspliceplate, mm Tension

Compression,shear

Min.length ofspliceplate, mm Tension

Compression,shear

Plywood/Plywood

7.5 9.512.515.5–20.5

200300350400

0.670.670.670.50

1.001.001.001.00

200300350400

0.850.850.850.85

1.001.001.001.00

OSB/OSB

9.5–11.0

12.5–18.5

200650*200800*

0.400.700.300.50

0.400.700.300.50

200

200

0.90

0.85

0.90

0.85

Lumber/OSB

9.5–11.0

12.5–18.5

200250*200300*

0.600.750.400.55

0.600.750.400.55

200

200

0.90

0.85

0.90

0.85

*For intermediate OSB splice plate lengths, the stress joint factor shall be obtained by linear interpolation.

7.4.5 Factor KF for Preserved Wood FoundationsFor plywood in preserved wood foundations supported at intervals not exceeding 815 mm, the end usefactor for panel bending and planar shear shall be KF = 1.15. For all other properties, KF = 1.0.

7.5 Resistance of Structural Panels

7.5.1 Stress OrientationStructural panels are orthotropic materials, and the specified strength capacities used in calculations shallbe those for the orientation of the face grain (plywood) or the orientation of the major axis (OSB)intended in the design.


72 August 2001

Mr

NTp

d2

p

6

7.5.2 Bending as a PanelThe factored bending resistance of a structural panel in the plane perpendicular to the plane of the panelshall be taken as

Mr = NMpbp

whereN = 0.95Mp = mp(KDKSKTKF) for plywood

= mp(KDKSKT) for OSBmp = specified strength capacity in bending (plywood — Tables 7.3A and 7.3B; OSB — Tables 7.3C

and 7.3D), NCmm/mmbp = width of panel, mm

7.5.3 Bending on EdgeThe factored bending resistance of structural panels loaded on edge in the plane of a panel that isadequately braced to prevent lateral buckling shall be taken as

whereN = 0.95Tp = tp(KDKSKT)tp = specified strength capacity in tension (plywood — Tables 7.3A and 7.3B; OSB — Tables 7.3C

and 7.3D), N/mmdp = depth of panel in plane of bending, mm

7.5.4 Planar Shear

7.5.4.1 Planar Shear Due to BendingThe factored resistance in planar shear for structural panels subjected to bending shall be taken as

Vrp = NVpbbp

whereN = 0.95Vpb = vpb(KDKSKTKF) for plywood

= vpb(KDKSKT) for OSBvpb = specified strength capacity in planar shear (due to bending) (plywood — Tables 7.3A and 7.3B;

OSB — Tables 7.3C and 7.3D), N/mm

7.5.4.2 Planar Shear in Structural Panel Splice or Gusset PlateThe factored resistance in planar shear developed by a glued structural panel splice or gusset plate, or bythe splice plates at a structural panel butt joint, shall be taken as

Vrp = NVpfAc

whereN = 0.95Vpf = vpf(KDKSKT)vpf = specified strength capacity in planar shear (due to in-plane forces) (plywood — Tables 7.3A

and 7.3B; OSB — Tables 7.3C and 7.3D), MPaAc = contact area of splice or gusset plate on one side of joint, mm2


August 2001 73

Vr

NVp

2dp

3

7.5.5 Shear-through-Thickness of Structural Panel

7.5.5.1 Shear Due to Bending of Structural Panel on EdgeThe factored resistance in shear through the thickness of a structural panel due to bending in the planeof the panel shall be taken as

whereN = 0.95Vp = vp(KDKSKT)vp = specified strength capacity in shear-through-thickness (plywood — Tables 7.3A and 7.3B;


7.5.5.2 Shear-through-Thickness in Structural Panel Splice or GussetPlateThe factored shear-through-thickness resistance developed by a structural panel splice or gusset plateshall be taken as

Vr = NVpLG

whereN = 0.95Vp = vp(KDKSKT)vp = specified strength capacity in shear-through-thickness (plywood — Tables 7.3A and 7.3B;

OSB — Tables 7.3C and 7.3D), N/mmLG = length of splice or gusset plate subjected to shear, mm

7.5.6 Compression Parallel to Panel EdgeThe factored compressive resistance parallel to a laterally supported panel edge shall be taken as

Pr = NPpbp

whereN = 0.95Pp = pp(KDKSKT)pp = specified strength capacity in axial compression (plywood — Tables 7.3A and 7.3B;


7.5.7 Tension Parallel to Panel EdgeThe factored tensile resistance parallel to a panel edge shall be taken as

Tr = NTpbn

whereN = 0.95 for all plywood thicknesses and number of plies except 3- and 4-ply layups stressed

perpendicular to face grain= 0.60 for 3- and 4-ply plywood layups stressed perpendicular to face grain= 0.95 for OSB

Tp = tp(KDKSKT)tp = specified strength capacity in axial tension (plywood — Table 7.3A and 7.3B; OSB — Tables 7.3C

and 7.3D), N/mmbn = net width of panel after cutting of holes, etc, mm


74 August 2001

7.5.8 Compressive Resistance Perpendicular to Face (Bearing)The factored bearing resistance normal to plane of panel shall be taken as

Qr = NQpAb

whereN = 0.95Qp = qp(KDKSKT)qp = specified strength capacity in bearing normal to plane of panel (plywood — Tables 7.3A and 7.3B;

OSB — Tables 7.3C and 7.3D), MPaAb = bearing area, mm2

8. Composite Building Components

8.1 ScopeClause 8 provides design equations and data for glued composite building components using plywood,OSB, and lumber or glued-laminated timber. The design provisions apply, provided that glue joints aremade in strict conformance to the requirements of the manufacturer of the adhesive used in thefabrication of these composite building components.Note: Clause 8 does not apply to proprietary structural wood products covered by Clause 13.

8.2 Materials

8.2.1 GeneralThe provisions in Clauses 8.3 to 8.6 apply to material as specified in Clause 5 for lumber, Clause 6 forglued-laminated timber, Clause 7 for plywood and OSB, and Clause 8.2.2 for adhesives.

8.2.2 Adhesives for Structural ComponentsAdhesives for the assembly of structural components shall meet the requirements of CSAStandard O112.7.

8.2.3 LumberThe provisions in Clauses 8.3 to 8.6 apply to lumber that is graded in accordance with NLGA StandardGrading Rules for Canadian Lumber and identified by the grade stamp of an association or independentgrading agency in accordance with the provisions of CSA Standard CAN/CSA-O141.

8.2.4 GlulamThe provisions in Clauses 8.3 to 8.6 apply to glued-laminated timber that is manufactured in accordancewith CSA Standard CAN/CSA-O122.

8.3 Stress Joint Factor, XJ

8.3.1 Joint RequirementsStress joint factors, XJ, in Clauses 8.3.2 and 8.3.3 apply to glued plywood and OSB stress joints fabricatedaccording to the requirements of Clause 8.4.

8.3.2 Scarf JointsThe stress joint factor for plywood scarf joints across the face grain or for OSB scarf joints across themajor axis stressed in tension, compression, or shear-through-thickness shall be as given in Table 7.4.4.1.


August 2001 75

8.3.3 Butt Joints

8.3.3.1 GeneralFor the length of splice plates perpendicular to the joint, the stress joint factors for butt joints across theface grain of plywood or the major axis of OSB stressed in tension, compression, or shear-through-thickness shall be as given in Table 7.4.4.2.

8.3.3.2 Butt Joints with Short Plywood Plates in CompressionFor plywood butt joints with splice plates shorter than the minimum length shown in Table 7.4.4.2, thestress joint factor for compression shall be reduced in direct proportion to such reduction in length.

8.4 Construction Requirements for Stress Joints

8.4.1 Types of Stress JointsJoints transmitting forces from one panel to another may be either scarf joints or butt joints.

8.4.2 Adhesives for Stress JointsAdhesives for the assembly of stress joints shall meet the requirements of Clause 8.2.2.

8.4.3 Scarf Joints

8.4.3.1 Scarf Joints in ShearThe slope of plywood scarf joints shall be not steeper than 1:8. The slope of OSB scarf joints shall not besteeper than 1:4.

8.4.3.2 Scarf Joints in Tension, Compression, or BendingThe slope of plywood scarf joints shall be not steeper than 1:5. The slope of OSB scarf joints shall not besteeper than 1:4.

8.4.4 Butt Joints

8.4.4.1 Splice Plates for Butt JointsButt joints shall be backed on one or both sides of the panel by a panel splice plate of a type and gradeat least equal to the panel being spliced. The splice plate shall be centred on the joints and glued toboth panels meeting at the joint. The splice plate shall be oriented with its major axis perpendicular tothe joint.

8.4.4.2 Splice Plate ThicknessSplice plates shall have a minimum thickness equal to that of the panel being spliced.

8.4.4.3 Butt Joints in ShearSplice plates stressed in shear shall have a length in the direction perpendicular to the joint equal to 12times the thickness of the butt-jointed panel and shall have a width equal to the full depth or width ofthe panel between framing members.

8.4.4.4 Butt Joints in TensionSplice plates stressed in tension shall have a minimum length as shown in Table 7.4.4.2.

8.4.4.5 Butt Joints in CompressionSplice plates stressed in compression may have a length as shown in Table 7.4.4.2. For plywood joints, ifshorter lengths are used, the strength of the joint shall be reduced as indicated in Clause 8.3.3.2.


76 August 2001

hc = bghc

ht

h

bg

bg

ccyc

ctyt

hc—2

ht—2

ht = bg

Neutral axis

Compression face

Tension face

(EΙ)e

( Ba)K

S

ct

3 cc

3

3(EΙ)

fKSE

Mr

NFcKZc

(EΙ)e

EKSEcc

8.5 Plywood and OSB Web Beams

8.5.1 GeneralA panel web beam shall have one or more plywood or OSB webs glued or nailed/glued at upper andlower edges to sawn lumber or glued-laminated timber flanges, with lumber stiffeners at intervals alongthe web to prevent buckling. (See Figure 8.5.1.)

Figure 8.5.1Panel Web Beam Dimensions (mm)

8.5.2 Effective StiffnessThe effective stiffness, (EI)e, of a panel web beam shall be taken as

where(EBa) = sum of axial stiffness of panel webs (Tables 7.3A, 7.3B, 7.3C, and 7.3D), N/mmKS = service condition factor for web material (Table 7.4.2)(EI)f = stiffness of flanges with respect to neutral axis of composite section, N/mm2

KSE = service condition factor for modulus of elasticity of flange (Table 5.4.2 for sawn lumber andTable 6.4.2 for glulam)

8.5.3 Bending ResistanceThe factored bending moment resistance of a panel web beam shall be the lesser of the factoredresistance of the tension or compression flanges determined as follows:(a) compression flange

)


August 2001 77

Mr

NFtKZt

(EΙ)e

EKSEct

Vr

NVpXJ

(EΙ)e

EKSEQf

0.5( Ba)K

Sc2

w

Vrp

NVg( b

gXv)(EΙ)

e

EKSEQf

whereN = 0.8 for sawn lumber

= 0.9 for glulamFc = fc(KDKScKTKH)fc = specified strength of flange in compression (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn

lumber and Table 6.3 for glulam), MPaKH = system factor (Clause 5.4.4 for sawn lumber and Clause 6.4.3 for glulam)KZc = size factor for compression for sawn lumber (Clause 5.4.5)E = modulus of elasticity of flange (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn lumber and

Table 6.3 for glulam), MPaKSE = service condition factor for modulus of elasticity of flange (Table 5.4.2 for sawn lumber and

Table 6.4.2 for glulam)cc = distance from neutral axis to compression face (Figure 8.5.1)

(b) tension flange

whereN = 0.9Ft = ft(KDKStKTKH)ft = specified strength of flange in tension (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn lumber

and Table 6.3 for glulam), MPaKZt = size factor for tension for sawn lumber (Table 5.4.5)E = modulus of elasticity of flange (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn lumber and

Table 6.3 for glulam), MPact = distance from neutral axis to tension face (Figure 8.5.1)

8.5.4 Web Shear-through-ThicknessThe factored shear resistance of the web of a panel web beam at its neutral axis shall be taken as

whereN = 0.95Vp = (Evp)(KDKSKT)Evp = sum of specified strengths of all panel webs in shear-through-thickness (Tables 7.3A, 7.3B, 7.3C,

and 7.3D), N/mmXJ = stress joint factor (Clause 8.3)E = modulus of elasticity of flange (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn lumber and

Table 6.3 for glulam), MPaQf = moment of area of flange about neutral axis, mm3

EBa = sum of specified axial stiffness for all panel webs (Tables 7.3A, 7.3B, 7.3C, and 7.3D), N/mmcw = greatest distance from neutral axis to outer edge of web, mm

8.5.5 Flange-Web ShearThe factored shear resistance of the glued area between the flange and web of a panel web beam shallbe the lesser of the shear capacities of the web or flange components determined as follows:

whereEbg = sum of contact widths between flange and webE = modulus of elasticity of flange (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn lumber and

Table 6.3 for glulam), MPa


78 August 2001

∆s

BaMh 2X

s

Bv(EΙ)

e

Qf = moment of area of flange about neutral axis, mm3

(a) for webN = 0.95Vg = vpf(KDKSKT)vpf = specified strength in planar shear (Tables 7.3A, 7.3B, 7.3C, and 7.3D), MPaXv = shear modification factor (Figure 8.5.5)

(b) for flangeN = 0.9Vg = fv(KDKSvKT)fv = specified strength in shear (Clauses 5.3.1 and 5.3.2 for sawn lumber and Table 6.3 for glulam),

MPaXv = 2.00

8.5.6 DeflectionDeflection shall be calculated as the sum of the deflections due to moment, using the effective stiffness,(E3)e, determined in accordance with Clause 8.5.2, and due to shear as determined by the followingformula:

whereBa = specified axial stiffness (Tables 7.3A, 7.3B, 7.3C, and 7.3D), N/mmM = maximum bending moment due to specified loads, N/mmh = height of web beam (Figure 8.5.1), mmXs = section shear coefficient (Figure 8.5.6)Bv = specified shear rigidity (Tables 7.3A , 7.3B, 7.3C, and 7.3D), N/mm


August 2001 79

bg = Contact width [mm]bg

amin[mm]

amax[mm]

3.0

2.0

2.5

1.5

0.5

Shea

r m

odifi

catio

n fa

ctor

, Xv

1.0

0.00.0 0.2 0.4

aminamax

———

0.6 0.8 1.0

bg = 19

bg = 25

bg = 32

bg = 38

bg = 51

bg = 64

bg = 76bg = 89

bg = 102bg = 114bg = 127bg = 140

Notes:(1) Stressed skin panelsAt an inside web, amin = amax

At an outside webamin = the overhang at the edgeamax = one-half the clear spacing between the outside web and the adjacent web(2) Panel web beamsamin = 0(3) For all other cases (splice plates, etc), the unmodified specified strength capacity in planar shear shall be used.

Figure 8.5.5Shear Modification Factor, Xv


80 August 2001

t tth

bt bt

hf

hf

h

hf

hf

0.60

0.50

0.40

0.30

0.20

0.100 0.10 0.20

0.10t— =bt

0.12

0.14

0.16

0.18

0.20

0.24

0.28

0.320.36

0.400.500.60

1.00

Ratio of depth of a flange to depth of beam, hf—h

Sect

ion

shea

r co

effic

ient

, Xs

0.30 0.40 0.50

Note:The section shear coefficient is a geometrical property of a beam section that depends on the shape of the cross-sectionand arises because of nonuniform distribution of shearing stresses across the section. It can be derived using fundamentalengineering theory and evaluated for any beam geometry from the formula.

whereXs = section shear coefficientI = moment of inertia (mm4)h = overall beam depth (mm)Q = first moment of beam (mm3)bx = width of beam carrying the shear associated with Q (mm)This figure is valid only for box and I-beams symmetrical about 2 axes.

Xs =1

I h2

Q2dybx

y=h

y=0

Figure 8.5.6Section Shear Coefficient, Xs


August 2001 81

(EΙ)e

(EΙ)wKSE

bf(B

aty2

tBacy2

c)K

S

8.5.7 Lateral Stability of Panel Web BeamsLateral stability of a beam shall be determined by considering the flange as a column that tends todeflect sideways between points of support, or by application of one of the following rules:(a) if the ratio of the moment of inertia of the cross-section about the neutral axis to the moment ofinertia about the axis perpendicular to the neutral axis does not exceed 5:1, no lateral support isrequired;(b) if the ratio of the moments of inertia is greater than 5:1 but does not exceed 10:1, the ends of thebeam shall be held in position at the bottom flange at supports;(c) if the ratio of the moments of inertia is greater than 10:1 but does not exceed 20:1, the beam shallbe held in line at the ends;(d) if the ratio of the moments of inertia is greater than 20:1 but does not exceed 30:1, one edge shallbe held in line;(e) if the ratio of the moments of inertia is greater than 30:1 but does not exceed 40:1, the beam shallbe restrained by bridging or other bracing at intervals of not more than 2400 mm; or(f) if the ratio of the moments of inertia is greater than 40:1, the compression flanges shall be fullyrestrained.

8.5.8 StiffenersLoad distribution stiffeners shall be provided at reaction points and at the location of heavy concentratedloads. These stiffeners shall be adequately fastened to the webs and shall bear on the inner surfaces ofthe top and bottom flanges. The stiffeners shall be made as wide as the flanges, and their dimensionsparallel to the span shall be adequate to support the applied concentrated loads or reactions. The cross-sectional area of a load-bearing stiffener shall be such that the factored resistance of the flange materialperpendicular to grain is not less than the concentrated load or the reaction due to the factored loads.

8.5.9 Web StabilizersWeb-stabilizing stiffeners shall be provided as necessary to prevent buckling of the webs.

8.6 Stressed Skin Panels

8.6.1 GeneralA stressed skin panel shall have continuous or spliced longitudinal web members and continuous orspliced panel flanges on one or both panel faces, with the flanges glued to the web members. (SeeFigure 8.6.1.)

8.6.2 Effective StiffnessThe effective stiffness, (EI)e, of a stressed skin panel shall be taken as

where(EI)w = stiffness of lumber webs, NCmm2

Bat = specified axial stiffness of tension flange (Ba for appropriate panel thickness in Tables 7.3A,7.3B, 7.3C, and 7.3D), N/mm

Bac = specified axial stiffness of compression flange (Tables 7.3A, 7.3B, 7.3C, and 7.3D), N/mm bf,yt,yc = panel dimensions as per Figure 8.6.1, mm


82 August 2001

hc

yccc

hc—2

ytct

ht—2

ht

hw

bg bg

bf

sTension face

Compression faceNeutral plane

Mr

NTpXJXG

(EΙ)e

BaKSct

Mr

NPpXJXG

(EΙ)e

BaKScc

Mr

NFbKZbKLXG

(EΙ)e

EKSEcw

Figure 8.6.1Stressed Skin Panel Dimensions, mm

8.6.3 Bending Resistance

8.6.3.1 Bending along Stressed Skin Panel SpanThe factored bending moment resistance along the direction of the webs of a stressed skin panel shall bethe least of the factored resistances of the tension or compression flanges or the web determined asfollows:(a) tension flange

whereN = 0.95Tp = tp(KDKSKT)tp = specified strength capacity of flange in axial tension (Tables 7.3A, 7.3B, 7.3C, and 7.3D), N/mmXJ = stress joint factor (Clause 8.3)Ba = specified axial stiffness (Tables 7.3A, 7.3B, 7.3C, and 7.3D), N/mm

(b) compression flange

whereN = 0.95Pp = pp(KDKSKT)pp = specified strength capacity of flange in axial compression (Tables 7.3A, 7.3B, 7.3C, and 7.3D),

N/mmXG = panel geometry reduction factor (Clause 8.6.3.2)

(c) web

whereN = 0.9Fb = fb(KDKSbKTKH)fb = specified strength in bending of webs (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn lumber

and Table 6.3 for glulam), MPa


August 2001 83

Vr

NFvKNKZv

(EΙ)ebg

EKSE

Qw

BaKSbfy

E = modulus of elasticity of web (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn lumber and Table6.3 for glulam), MPa

cw = greatest distance from neutral axis to outer edge of web, mm

8.6.3.2 Panel Geometry Reduction FactorThe panel geometry reduction factor, XG, shall be taken as

XG = 1 – 4.8(s/Rp)2

wheres = clear spacing between longitudinals, mmRp = span of stressed skin panel, mmNote: This formula accounts for shear lag and is valid for values of s/Rp ranging from 0.05 to 0.25.

8.6.3.3 Bending Perpendicular to Panel SpanThe factored bending resistance of the compression flange between web members shall be calculatedusing Clause 7.5.2.

8.6.3.4 Buckling of Compression FlangeThe compression flange of a stressed skin panel shall be designed according to principles of engineeringmechanics to prevent elastic buckling failure. If a detailed analysis is not made, such a condition isassumed to be met if(a) s #50 hc, for panels with their major axis parallel to the span (Rp); or(b) s #40 hc, for panels with their major axis perpendicular to the span (Rp)where s and hc are as per Figure 8.6.1. Clause A8.6.3.4 provides a detailed analysis for stressed skin panels with a plywood compression flange.Note: See Clause A8.6.3.4 for additional information on buckling of compression flanges.

8.6.3.5 Shear in Plane of PliesThe factored planar shear resistance of the compression flange in a stressed skin panel shall be calculatedusing Clause 8.6.3.6.

8.6.3.6 Shear ResistanceThe factored shear resistance at the neutral plane of a stressed skin panel shall be taken as

whereN = 0.9Fv = fv(KDKSvKTKH)fv = specified strength in shear of webs (Clauses 5.3.1 and 5.3.2 for sawn lumber and Table 6.3 for

glulam), MPaKN = notch factor (Clauses 5.5.5.4 and 6.5.7.2.2)KZv = size factor in shear (Clause 5.4.5)bg = contact width between flange and web (Figure 8.6.1)E = modulus of elasticity of web (Tables 5.3.1A to 5.3.1D, 5.3.2, and 5.3.3 for sawn lumber and

Table 6.3 for glulam), MPaEQw = sum of moments of area of all webs about neutral plane, mm3

Ba = specified axial stiffness (Tables 7.3A, 7.3B, 7.3C, and 7.3D), N/mmbf = width of flange, mmy = the greater value of yt or yc, mm


84 August 2001

Vrp

NVg

(EΙ)e(bgXv)

BaKSbpy

8.6.3.7 Flange-Web ShearThe factored shear resistance of the glued area between the flange and the web of a stressed skin panelshall be taken as the lesser of the shear capacities based on flange or web components determined asfollows:

whereBa = specified axial stiffness (Tables 7.3A, 7.3B, 7.3C, and 7.3D), N/mmy = the greater value of yt or yc, mm,

and

(a) for flangeN = 0.95Vg = vpf(KDKSKT)vpf = specified strength capacity in planar shear (Tables 7.3A, 7.3B, 7.3C, and 7.3D), MPaXv = shear modification factor (Figure 8.5.5)

(b) for webN = 0.9Vg = fv(KDKSKT)fv = specified strength in shear (Clauses 5.3.1 and 5.3.2 for sawn lumber and Table 6.3 for glulam),

MPaXv = 2.00

8.6.3.8 DeflectionThe deflection of stressed skin panels shall be calculated using the effective stiffness, (EI)e, determined inaccordance with Clause 8.6.2, multiplied by the panel geometry reduction factor, XG, determined inaccordance with Clause 8.6.3.2.

9. Shearwalls and Diaphragms

9.1 ScopeClause 9 provides requirements and data for the design of wood structures subject to lateral forces.Note: Wind and earthquake loads are examples of lateral forces.

9.2 Materials

9.2.1 GeneralThe provisions in Clauses 9.3 to 9.5 apply to materials as specified in Clause 5 for lumber, Clause 6 forglued-laminated timber, Clause 7 for structural panels, and Clause 10 for fastenings, and to additionalmaterials specified in Clause 9.2.2.

9.2.2 Additional MaterialsThe provisions in Clauses 9.3 to 9.5 are also applicable to OSB and waferboard manufactured to meetthe requirements of CSA Standard O437.0, gypsum wallboard conforming to Type X (fire-rated) inASTM Standard C 36, and Type 3 (proprietary) design-rated OSB as specified in Clause 13.3 of thisStandard.


August 2001 85

9.3 Design of Shearwalls and Diaphragms

9.3.1 General

9.3.1.1 Standard MethodsShearwalls and diaphragms may be designed using the provisions for nailed shear panels using structuralwood panels, gypsum wallboard, and diagonally sheathed shear panels (Clauses 9.5.1 and 9.5.2).

9.3.1.2 Alternative MethodsAlternative methods of analysis utilizing the factored lateral strength resistance of nails, spikes, or bolts toachieve ductility and the factored resistance of materials specified elsewhere in this Standard may beused, provided it can be demonstrated that such alternative methods of analysis are based on recognizedprinciples of mechanics.

9.3.2 Resistance to Overturning

9.3.2.1 Shearwall Segments with Hold-downs Where the factored dead loads are not sufficient to prevent overturning, hold-down connections (seeFigure 9.3.2(a)) shall be designed to resist the factored uplift forces and transfer the forces through acontinuous load path to the foundation.

9.3.2.2 Shearwall Segments without Hold-downsWhere the factored dead loads are not sufficient to prevent overturning, and hold-down connections arenot used, anchorage (see Figure 9.3.2(b)) on the bottom plate within 300 mm from both ends of theshearwall segment shall transfer the uplift force “Rij” (Clause 9.4.5.2) to the supporting structure (i.e., tothe top plate of the shearwall below, or the foundation).


86 August 2001

(a) Hold-downs

(b) Anchorages

Shearwall-to-shearwall Shearwall-to-foundation

Shearwall-to-shearwall Shearwall-to-foundation

Hold-downbetweenfloors

Hold-downwith anchorbolt

Bolt or threadedrod Anchor

bolt

Notes:(1) These are examples only. Other types of hold-downs and anchorages may be used.(2) Hold-downs as per Clause 9.3.2.1 provide a continuous direct load path, typically between upper storey shearwallchords and lower storey chords, beams, or foundations.(3) Anchorages as per Clause 9.3.2.2 typically transfer loads from the sill plate of the upper storey shearwall segmentto the lower storey top plates, beams, or foundations.

Figure 9.3.2Examples of Hold-downs and Anchorages

9.3.3 Shearwalls with Segments

9.3.3.1 GeneralThe factored shear resistance of a shearwall shall equal the sum of the factored shear resistance of thewall segments determined according to Clause 9.5.1. The factored shear resistance of the shearwall shallbe determined for lateral loads acting in opposite directions.



9.3.3.2 Shearwall Segment Aspect RatioThe maximum aspect ratio (height-to-length ratio) of a shearwall segment shall be 3.5:1. The height isdefined as the height from the underside of the bottom shearwall plate to the topside of the topshearwall plate within a storey.

9.3.3.3 Shearwalls with OpeningsShearwalls with openings shall be analyzed as the sum of the separate shearwall segments. Thecontribution of sheathing above and below openings shall not be included in the calculation of shearwallresistance.

9.3.3.4 Shearwalls with Dissimilar MaterialsExcept as allowed in Clause 9.3.3.5, shearwalls constructed with dissimilar materials, thicknesses, or nailspacings along the length of the shearwall shall be analyzed as the sum of the separate shearwallsegments.

9.3.3.5 Alternative Method for Shearwalls with Dissimilar MaterialsShearwalls constructed with dissimilar materials, thicknesses, or nail spacings along the length of theshearwall may be analyzed, in accordance with Clause 9.5.1, as a shearwall of uniform construction,provided that the least value of v K K J J is assumed to apply over the entire shearwall.d D SF ub sp

9.3.4 Shearwalls with Multiple Layers

9.3.4.1 A Shearwall with Two Layers of Panels on One Side The factored shear resistance for a shearwall with two layers of the same or different panels applied toone side is determined by the first (inside) layer of panels, except as allowed in Note 5 to Table 9.5.1A.

) 9.3.4.2 Two-Sided ShearwallThe factored shear resistance from each side of the same shearwall is cumulative when panels of thesame or different materials are applied on both sides. Note: See appropriate seismic force modification factor, R ., in Clauses 9.5.3 and 9.5.4.d

9.3.5 Concrete or Masonry Wall Anchorage

9.3.5.1 Anchorage DesignWhere wood roofs and floors are used to provide lateral support to concrete and masonry walls, theyshall be anchored to these walls. The anchorage shall provide a direct connection between the walls andthe roof or floor construction. The connections shall be capable of resisting the lateral force induced bythe wall, but not less than 3 kN per lineal metre of the wall.

9.3.5.2 Anchorage DetailsAnchorage of concrete or masonry walls shall not be accomplished by use of toe-nails or nails subject towithdrawal, nor shall wood ledgers be designed to resist tensile stresses perpendicular to grain.

9.3.6 Shearwall AnchorageThe anchor bolts to resist lateral forces shall be designed in accordance with Clause 10.


9.4.1 Load Duration Factor, K DThe specified shear strengths for wood-based shearwalls and diaphragms shall be multiplied by the loadduration factor, K , given in Clause 4.3.2.DNote: Specified shear strengths for gypsum wallboard shearwalls apply only to short-term load duration, and K is notDapplicable.

Maximum 2440 mm

Table 9.4.4Strength Adjustment Factor, Jub,

for Horizontally Sheathed Unblocked Shearwalls*

150150

Nail spacing atsupported edges,mm

150300

Nail spacing atintermediate studs,mm

1.00.8

Stud spacing, mm

0.80.6

0.60.5

0.50.4

300 400 500 600

*Specified shear strength of an unblocked shearwall shall be calculated by multiplying the strength adjustment factor by the specified shear strength of a blocked shearwall with 600 mm stud spacing, and with nails spaced at 150 mm on centre around panel edges and 300 mm on centre along intermediate framing members.Note: Strength adjustment factor shall only be applicable to structural wood-based panels.

Horizontal panels,no blocking



9.4.2 Service Condition Factor, KSFThe specified shear strengths for wood-based shearwalls and diaphragms shall be multiplied by theservice condition factor, K , given in Table 10.2.1.5 for lateral loads on nails.SF

9.4.3 Species Factor for Framing Material, JspThe specified shear strengths for wood-based shearwalls and diaphragms shall be multiplied by thespecies factor for framing material, J , as given in Table 9.4.3.sp

Table 9.4.3Species Factor for Framing Material, Jsp

J Visually graded lumber Glued-laminated timber S-P-F,* MPasp

MSR (or MEL) E-Grade of

1.0 Douglas Fir-Larch Douglas Fir-Larch 13 800 to 16 5000.9 Hem-Fir N/A 12 400 to 13 1000.8 S-P-F Spruce-Pine 8300 to 11 7000.7 Northern Species N/A N/A

*For other species of MSR or MEL lumber, use visually graded lumber values.

9.4.4 Strength Adjustment Factor for Unblocked Shearwalls, JubThe specified shear strengths for horizontally sheathed unblocked shearwalls sheathed with wood-basedpanels shall be multiplied by the strength adjustment factor J , as given in Table 9.4.4. ub


August 2001 89

= + + − ≤

2ij s s

ndhd s s

P H HJ 1 2 1.0

V L L

Fi

Vrs

Vrs

Jhd

VhdP

Vhd

1.0

9.4.5 Hold-down Effect Factor for Shearwall Segments, Jhd

9.4.5.1 Shearwall Segments with Hold-downs to Resist All OverturningTension ForcesFor shearwall segments with hold-down connections that are designed to resist all of the factoredtension forces due to overturning

Jhd = 1.0

9.4.5.2 Shearwall Segments without Hold-downsFor shearwall segments without hold-down connections at either end, and that meet the requirementsof Clauses 9.3.2.2 and 9.4.5.5 and the additional requirement that Pij is equal to or greater than zero

wherePij = factored uplift restraint force for storey “i” at the bottom of the end stud of a shearwall segment

“j”, kN (see Figure 9.4.5.2)Vhd = factored basic shear resistance, kN

= factored shear resistance of the shearwall segment calculated with Jhd = 1.0Hs = height of shearwall segment, mLs = length of shearwall segment, mNote: The following terms, required to determine the value of the variables used in calculating Jhd, are illustrated inFigure 9.4.5.2:qi = factored storey “i” dead load to resist overturning (includes only dead weight from current storey sill

plate to next storey floor or roof), kN/mRij = resultant overturning force at storey “i”, segment “j”, kNFij = factored shear load at storey “i” on the shearwall segment “j”, kN

Fi = total applied factored shear load on the shearwall at storey “i”, kNVrs = factored shear resistance of the shearwall segment calculated in accordance with Clause 9.5.1, kN'Vrs

= sum of factored shear resistances, kN, for each segment in a shearwall

9.4.5.3 Shearwall Segments with Hold-downs Only at the Bottom ofthe SegmentFor a lower-storey shearwall segment with hold-down connections at the bottom of the shearwallsegment and without hold-down connections at the top of the shearwall segment, where P is less thanzero

whereVhd = factored basic shear resistance, kN

= factored shear resistance of the shearwall segment calculated with Jhd = 1.0P = uplift restraint force at the top of the end stud of a shearwall segment, kN


90 August 2001

9.4.5.4 Shearwall Segments with Hold-downs Only on One SideFor a shearwall segment with hold-down connections only on one side of the segment(a) Jhd shall be determined according to Clause 9.4.5.1 if designed to resist all tension forces due tooverturning.(b) Jhd shall be determined according to Clause 9.4.5.2 if there is no hold-down on the tension side ofthe segment.(c) Jhd shall be determined according to Clause 9.4.5.3 if there is a hold-down only at the bottom of thetension side of a lower-storey segment.

9.4.5.5 Conditions for Shearwall Segments with Jhd<1.0The conditions for calculating Jhd in Clauses 9.4.5.2 to 9.4.5.4 are as follows:(a) The maximum nail diameter shall be 3.25 mm, and the minimum nail spacing shall be 100 mm.(b) The maximum specified shear strength, including both sides of a shearwall where applicable, shallbe 10.3 kN/m.(c) The height of the shearwall segment shall be less than 3.6 m.


9.5.1 Shear Resistance of Nailed ShearwallsThe factored shear resistance of nailed shearwalls of structural wood-based panels, gypsum wallboard, ordiagonal lumber sheathing, constructed in accordance with Clauses 9.5.3, 9.5.4, and 9.5.5, respectively,shall be determined as follows:

Vr = 'Vrs

whereVrs = factored shear resistance for each shearwall segment along the length of the shearwall, kN

The factored shear resistance for a shearwall segment of structural wood-based panels or diagonallumber sheathing shall be taken as

Vrs = N vdKDKSF JubJspJhdLw

whereN = 0.7vd = specified shear strength for shearwall segment with plywood, OSB, or waferboard (Table 9.5.1A)

or diagonal lumber sheathing (Clause 9.5.5), kN/mJub = strength adjustment factor for unblocked shearwalls (Clause 9.4.4)Jsp = species factor for framing material (Clause 9.4.3)Jhd = hold-down effect factor for shearwall segment (Clause 9.4.5)Lw = length of shearwall segment parallel to direction of factored load, m

The factored shear resistance for a shearwall segment of gypsum wallboard shall be taken as

Vrs = N vdJhdLw

whereN = 0.7vd = specified shear strength for shearwall segment sheathed with gypsum wallboard (Table 9.5.1B),

kN/mJhd = hold-down effect factor for shearwall segment (Clause 9.4.5)Lw = length of shearwall segment parallel to direction of factored load, m Note: See Clause A9.5.1 for additional information on shear resistance of nailed shearwalls.

L1 L3 L2

H

H

h2

h1

q2 F2

F1q1

qw2qw2

qw1qw1

qw2qw2

qw1qw1

q1q1

q2q2

P21

Ptop21

R22

P22

R21

F22F21

Ptop22

Ptop11

F12F11

Ptop12

P11R12 = F12 – P12P12

R11 R12

H + h1

L2

P12 = Ptop12 + qw1L2

2

Ptop12 = q1 –R22L2

2

R11 = F11 – P11H + h1

L1


2

Ptop11 = q1 –R21+ q1L1

2L3

2

R22 = F22 – P22H + h2

L2


2

Ptop22 = q2L2

2

R21 = F21 – P21H + h2

L1


2

Ptop21 = q2 + q2L1

2L3

2



Figure 9.4.5.2Multi-Storey Shearwall Force Diagrams



9.5.2 Shear Resistance of Nailed Diaphragms The factored shear resistance of nailed diaphragms of structural wood-based panels or diagonal lumbersheathing constructed in accordance with Clauses 9.5.3 and 9.5.5, respectively, shall be determined asfollows:

V = N v K K J Lr d D SF sp D

whereN = 0.7v = specified shear strength for diaphragms with plywood, OSB, or waferboard (Table 9.5.2) ord

diagonal lumber sheathing (Clause 9.5.5), kN/mJ = species factor for framing material (Clause 9.4.3)sp

L = dimension of diaphragm parallel to direction of factored load, mD

9.5.3 Nailed Shearwalls and Diaphragms Using Plywood, OSB, orWaferboard

) 9.5.3.1 GeneralShearwalls and diaphragms sheathed with plywood, OSB, or waferboard may be used to resist sheardue to lateral forces based on the specified shear strength given in Table 9.5.1A for shearwalls andTable 9.5.2 for diaphragms.Notes:(1) Seismic force modification factor, R ., is equal to 3 when nailed plywood, OSB, or waferboard shearwalls are considereddto resist lateral loads.(2) Table 9.5.3 provides an equivalence between tabulated thickness and panel marks.

9.5.3.2 Framing MembersFraming members shall be at least 38 mm wide and be spaced no greater than 600 mm apart inshearwalls and diaphragms. In general, adjoining panel edges shall bear and be attached to the framingmembers, and a gap of not less than 2 mm shall be left between wood-based panel sheets.

9.5.3.3 Framing and PanelsShearwalls and diaphragms using plywood, OSB, or waferboard shall be constructed with panels not lessthan 1200 × 2400 mm, except near boundaries and changes in framing, where up to two short ornarrow panels may be used. Panels for diaphragms shall be arranged as indicated in Table 9.5.2. Framing members shall be provided at the edge of all panels in shearwalls except horizontally sheathedunblocked shearwalls where blocking at the middle of the wall height is omitted. Shearwalls and diaphragms shall be designed to resist shear stresses only, and perimeter members shallbe provided to resist axial forces resulting from the application of lateral design forces. Perimetermembers shall be adequately interconnected at corner intersections, and member joints shall be splicedadequately. Panels less than 300 mm wide shall be blocked.

9.5.3.4 NailingThe nails and spacing of nails at shearwall and diaphragm boundaries and the edges of each panel shallbe as shown in Table 9.5.1A for shearwalls and in Table 9.5.2 for diaphragms. Nails shall be placed not less than 9 mm from the panel edge and shall be placed along all intermediateframing members at 300 mm on centre for floors, roofs, and shearwalls. Nails shall be firmly driven intoframing members but shall not be over-driven into sheathing. For structural wood-based sheathing, nailsshall not be over-driven more than 15% of the panel thickness.

) 9.5.4 Nailed Shearwalls Using Gypsum WallboardShearwalls using gypsum wallboard shall be constructed with panels not less than 1200 × 2400 mm,except near boundaries and changes in framing, where up to two short or narrow panels may be used.



Shearwalls sheathed with gypsum wallboard may be used to resist shear due to lateral forces based onthe specified shear strength given in Table 9.5.1B for shearwalls. Gypsum wallboard application nails or screws shall be placed not less than 9 mm from the panel edge. Gypsum wallboard shall be used in combination with structural wood-based panels. The factored shearresistance of gypsum wallboard shall be equal to or less than the percentage of storey shear forces inTable 9.5.4. The application of gypsum wallboard shall be restricted to platform frame constructionwhere the height of a storey does not exceed 3.6 m.Notes:(1) Seismic force modification factor, R , is equal to 2 and system overstrength factor, R , is equal to 1.7 when gypsumd o

wallboard is considered to resist lateral loads.(2) There should exist a balanced spatial distribution of the gypsum wallboard and wood-based panels resisting shear in agiven direction in a particular storey.

9.5.5 Nailed Shearwalls and Diaphragms Using Diagonal LumberSheathing

9.5.5.1 GeneralNailed shearwalls and diaphragms as described in Clauses 9.5.5.2 to 9.5.5.4 may be used to resistlateral forces. The specified shear strength, v , with a single layer of diagonally sheathed lumberd

(Clause 9.5.5.2) shall be taken as 8 kN/m; that for a double layer of diagonally sheathed lumber(Clause 9.5.5.3) as 24 kN/m.

9.5.5.2 Single-Layer Diagonal SheathingSingle-layer diagonal sheathing shall be made up of 19 mm boards laid at an angle of approximately 45°to supports. Boards shall be nailed to each intermediate member with not less than two common nails(d = 3.25 mm) for 19 × 140 mm boards and three common nails (d = 3.25 mm) for 19 × 184 mm orwider boards. One additional nail shall be used in each board at shear panel boundaries. End joints in adjacent rows of boards shall be staggered by at least one stud or joist space, and joints onthe same support shall be separated by at least two rows of boards. Shearwalls and diaphragms made up of 38 mm thick diagonal sheathing using common nails(d = 4.06 mm) may be used at the same shear values and in the same locations as for 19 mm boards,provided that there are no splices in adjacent boards on the same support and the supports are not lessthan 89 mm in depth or 64 mm in thickness.

9.5.5.3 Double-Layer Diagonal SheathingDouble-layer diagonal sheathing shall conform to Clause 9.5.5.2 and shall consist of two layers ofdiagonal boards at 90° to each other on the same face of the supporting members.

9.5.5.4 Boundary MembersDiagonal sheathing produces a load component acting normal to the boundary members in the plane ofthe shear panel. Boundary members in diagonally sheathed shearwalls and diaphragms shall bedesigned to resist the bending stresses caused by the normal load component.

9.5.6 Moment Resistance of Nailed Shearwalls and Diaphragms

9.5.6.1 GeneralExcept as provided in Clause 9.5.6.2, the factored moment resistance of nailed shearwalls anddiaphragms shall be determined as

M = P hr r

whereP = factored axial tension and compression resistance of the elements resisting chord forces with duer

allowance being made for joints, N



h = centre-to-centre distance between moment resisting elements, mm= centre-to-centre distance between diaphragm chords in the design of diaphragms, mm= centre-to-centre distance between stud chords in shearwall segments designed with hold-down

connections at both ends of the shearwall segment, mm= length of shearwall segment minus 300 mm for shearwall segments designed without hold-down

connections at both ends of the segment, mm

9.5.6.2 Moment Resistance for Shearwall Segments without Hold-downsFor shearwall segments without hold-downs, moment resistance calculation specifically for design of thetension chords shall not be required.

9.6 Detailing Requirements

9.6.1 GeneralAll boundary members, chords, and struts of nailed shearwalls and diaphragms shall be designed anddetailed to transmit the induced axial forces. The boundary members shall be fastened together at allcorners.

9.6.2 Fastenings to Shearwalls and Diaphragms Fastenings and anchorages capable of resisting the prescribed forces shall be provided between theshearwall or diaphragm and the attached components.


August 2001 95

Vertical panels,with blocking

Horizontal panels,with blocking

Horizontal panels,with blocking

Vertical panels,no blocking

Table 9.5.1ASpecified Shear Strength, vd, for Shearwalls with

Framing of Douglas Fir-Larch (kN/m)

Minimumnominalpanelthickness,mm

Minimum nailpenetration inframing, mm

Commonnaildiameter,mm

Panel applied directly to framing

Nail spacing at panel edges, mm

150 100 75 50†

7.5§ 9.5 9.511.012.512.515.5

31313838384141

2.842.843.253.253.253.66‡3.66‡

4.95.46.0*6.5*7.18.49.2

7.3 8.2 8.7* 9.5*10.312.513.9

9.510.611.1*12.2*13.316.318.1

12.213.914.4*15.9*17.420.923.7

*The values for 9.5 mm and 11.0 mm panels applied directly to framing may be increased to values shown,respectively, for 11.0 mm and 12.5 mm panels, provided studs are spaced at a maximum of 400 mm on centre.

†Framing at adjoining panel edges shall be 64 mm lumber (or two 38 mm wide framing members connected totransfer the factored shear force) or wider, and nails shall be staggered where nails are spaced 50 mm on centre.‡Framing at adjoining panel edges shall be 64 mm lumber (or two 38 mm width framing members connected totransfer the factored shear force), or wider and nails shall be staggered where nails of 3.66 mm diameter havingpenetration into framing of more than 41 mm are spaced 75 mm or less on centre.§9.5 mm minimum recommended when applied directly to framing as exterior siding.Notes:(1) Tabulated values are applicable to nailed shear panels using structural wood-based panels based on dryservice conditions and standard duration of load.(2) All panel edges are backed with 38 mm or wider framing. Panels are installed either horizontally orvertically, with nails spaced at 300 mm on centre along intermediate framing members. For unblockedhorizontal panels, see Clause 9.4.4.(3) Where panels are applied on both faces of a wall and nail spacing is less than 150 mm on centre on eitherside, panel joints shall be offset to fall on different framing members or framing shall be 64 mm or thicker andnails on each side shall be staggered.(4) For panels applied over 12.7 mm or 15.9 mm gypsum wallboard, specified shear strength for the samethickness panel applied directly to framing may be used as long as minimum nail penetration (in the framing) issatisfied.(5) For shearwalls fabricated with nails having a diameter that deviates from those presented in the table (e.g.,power-driven nails), consult Appendix A9.5.1 for an appropriate modification factor, which should be applied tothe capacities given in the table. (6) For construction sheathing OSB, product specification shall also include a panel mark identifying an end-userating. Table 9.5.3 provides an equivalence between tabulated thicknesses and panel marks.


96 August 2001

Table 9.5.1BSpecified Shear Strength, vd, for Gypsum

Wallboard Shearwalls (kN/m)

Minimumnominal panelthickness, mm

Minimum nailand screwpenetration inframing, mm

Wallconstruction

Panels applied directly to framing

Nail and screw spacing at panel edges, mm

200 150 100

12.512.515.915.9

19191919

UnblockedBlockedUnblockedBlocked

1.21.41.51.7

1.41.71.72.2

1.62.12.12.5

Notes:(1) Tabulated values are based on dry service conditions and are applicable to wood framing of all species. Values forunblocked walls are given for 400 mm stud spacing, and shall be reduced by 20% for 500 mm stud spacing, and 40%for 600 mm stud spacing. Values for blocked walls are applicable to stud spacings from 400 to 600 mm.(2) Gypsum wallboard shall only be considered effective in resisting loads of short-term duration. Gypsum wallboardshall not be permitted in wet service conditions. (3) Tabulated values apply when gypsum wallboard is applied to framing with nails conforming to CSA Standard B111,gypsum board application nails — ring threaded. (4) Tabulated values apply when gypsum wallboard is applied to framing with wallboard screws conforming to ASTMStandard C 1002, Type W.(5) Space nails and screws at maximum 300 mm on centre along intermediate framing members.

© C

anadian Standards AssociationEngineering D

esign in Wood

August 200197

Table 9.5.2Specified Shear Strength, vd, for Diaphragms with Framing of Douglas Fir-Larch (kN/m)

Commonnaildiameter,mm

Minimumnailpenetrationin framing,mm

Minimum panelthickness,mm

Minimumwidth offramingmember,mm

Blocked diaphragms Unblocked diaphragms

Nail spacing (mm) atdiaphragm boundaries (allcases) and at continuouspanel edges parallel to load(cases 3 and 4 )

Nail spacing at 150 mm maximum atsupported edges150 100 64 50*

Nail spacing at other paneledges, mm Load perp. to unblocked

edges and continuouspanel joints (case 1)

All otherconfigurations(cases 2, 3, and 4)150 150 100 75

2.84 31 7.5 38 4.6 6.1 9.1 10.3 4.1 3.0

64 5.2 6.8 10.3 11.7 4.6 3.4

9.5 38 5.0 6.8 10.2 11.4 4.5 3.4

64 5.7 7.6 11.4 12.9 5.0 3.8

3.25 38 9.5 38 6.5 8.7 13.1 14.8 5.9 4.4

64 7.3 9.8 14.7 16.6 6.5 4.9

11.0 38 6.9 9.2 13.7 15.6 6.3 4.6

64 7.8 10.3 15.5 17.5 6.9 5.2

12.5 38 7.3 9.8 14.4 16.3 6.5 4.9

64 8.2 10.9 16.3 18.4 7.2 5.4

3.66† 41 12.5 38 7.9 10.5 15.6 17.8 6.9 5.2

64 8.8 11.7 17.7 20.0 7.9 5.9

15.5 38 8.7 11.6 17.4 19.8 7.8 5.9

64 9.8 13.0 19.6 22.3 8.7 6.5

18.5 64 — 17.5‡ 25.4‡ — — —

89 — 20.4‡ 29.2‡ — — —(Continued)

CAN

/CSA-O

86-01 © C

anadian Standards Association

98

August 2001

Table 9.5.2 (Concluded)

*Framing at adjoining panel edges shall be 64 mm lumber (or a built-up column composed of two 38 mm width framing members connected to transfer the factoredshear force) or wider, and nails shall be staggered where nails are spaced 50 mm on centre.†Framing at adjoining panel edges shall be 64 mm lumber (or two 38 mm width framing members connected to transfer the factored shear force) or wider, and nailsshall be staggered where nails of 3.66 mm diameter having penetration into framing of more than 41 mm are spaced 75 mm or less on centre.‡Two lines of fasteners are required.Notes:(1) Tabulated values are based on dry service conditions and standard-term duration of load, and apply to nailed shear panels using structural wood-based panels. Space nails 300 mm on centre along intermediate framing members.(2) For diaphragms fabricated with nails having a diameter that deviates from those presented in the table (e.g., power-driven nails), consult Clause A9.5.1 for anappropriate modification factor, which should be applied to the capacities given in the table.(3) For Construction Sheathing OSB, product specification shall also include a panel mark identifying an end-use rating. Table 9.5.3 provides an equivalence betweentabulated thicknesses and panel marks.

Load

Case 2Horizontal framingVertical blocking, if used

Load

Case 1Vertical framingHorizontal blocking, if used

Load Continuouspanel joint

Case 3Horizontal framingVertical blocking, if used

Load

Case 4Vertical framingHorizontal blocking, if used

Continuouspanel joint



Table 9.5.3Panel Marking Equivalence in Shearwall and Diaphragm Tables

In shearwall Table 9.5.1A In diaphragm Table 9.5.2

Minimum nominal Minimum nominalthickness, mm Minimum panel mark thickness, mm Minimum panel mark

7.5 2R20 7.5 2R20 9.5 2R24 9.5 2R2411.0 1R24/2F16 11.0 1R24/2F1612.5 2R32/2F16 or 1F16 12.5 2R32/2F1615.5 2R40/2F20 15.5 2R40/2F20 or 1F20

18.5 2R48/2F24 or 1F24

Notes:(1) For OSB panels rated to CSA Standard CAN/CSA-O325.0, the minimum nominal thickness may be 0.5 mm less thanthe thickness shown above. No adjustment to the tabulated shear strength values is required.(2) For alternative panel marks meeting the minimum requirements, see Clause A7.2.2.2.

) Table 9.5.4Maximum Percentage of Total Shear ForcesResisted by Gypsum Wallboard in a Storey

Storey 4-storey building 3-storey building 2-storey building 1-storey building

Percentage of shear forces

4th 80 — — —

3rd 60 80 — —

2nd 40 60 80 —

1st 40 40 60 80

Notes:(1) A force modification factor of R = 2.0 and a system overstrength factor of R = 1.7 are used when gypsum wallboardd osheathing is considered to resist lateral loads.(2) Maximum storey height shall not exceed 3.6 m.

10. Fastenings

10.1 ScopeClause 10 provides criteria for the engineering design and appraisal of connections using split ring andshear plate connectors, bolts, drift pins, lag screws, timber rivets (also known as glulam rivets), trussplates, nails, spikes, and joist hangers.Note: Lateral resistance values for bolts, drift pins, and lag screws are based on relative density of the wood material. Reference density values are given in Table A10.1.

10.2 General Requirements

10.2.1 All FasteningsNote: Joint details should be avoided where shrinkage of the wood can lead to excessive tension perpendicular to grain.

10.2.1.1The tables are predicated on the requirement that the projecting end of a member shall not be trimmedor otherwise altered in such a manner as to reduce the specified minimum end distance.

d

Fastening(s)

de

de



10.2.1.2Under severe conditions conducive to corrosion, connection design should provide adequate protection.

10.2.1.3Joints made using hard maple, soft maple, elm, beech, black oak, white oak, or birch may be assignedthe same resistances as the D Fir-L species group.

10.2.1.4Where a fastening or group of fastenings exerts a shear force on a member, the factored shear resistanceof the member as calculated in Clauses 5.5.5 and 6.5.7 shall be based upon the dimension d shown ine

Figure 10.2.1.4, instead of the dimension d. Dimension d is defined as the distance, measurede

perpendicular to the axis of the member, from the extremity of the fastening or group of fastenings tothe loaded edge of the member.

Figure 10.2.1.4Shear Depth

10.2.1.5 Service Condition Factor, K SFThe service condition factor, K , for fastenings is given in Table 10.2.1.5.SF

10.2.1.6 Load Duration Factor, KDThe load duration factor, K , for fastenings is given in Table 4.3.2.2.D

10.2.1.7 Treatment Factor, KTFor connections containing wood-based members treated with fire-retardant or other strength-reducingchemicals, strength capacities of connections shall be based on the documented results of tests that shalltake into account the effect of time, temperature, and moisture content. Test procedures shall meet therequirements of Clause 3.3.2.Note: The effects of fire-retardant treatments can vary depending on manufacturing materials and processes. See theCanadian Wood Council’s Commentary for additional explanation.

10.2.1.8Joints shall be assembled so that the surfaces are brought into close contact.


August 2001 101

Table 10.2.1.5Service Condition Factor, KSF, for Fastenings

Service conditions

Condition of lumber when fabricated

Seasoned(moisture content# 15%)

Unseasoned(moisturecontent > 15%)

Jointdetail*

Angle ofload tograinDry Wet Dry Wet

Timber rivets (also knownas glulam rivets):– lateral loads– withdrawal loads

1.001.00

0.80†

0.900.60

0.80†

All All

Split rings, shear plateconnectors, truss plates 1.00 0.67 0.80 0.67 All All

Bolts, drift pins, lag screws

1.001.001.001.00

0.670.670.670.67

1.001.000.400.40

0.670.670.270.27

ABBC

All 0E90EAll

Nails:– lateral loads– withdrawal loads

1.001.00

0.670.67

0.800.40

0.670.40

AllAll

All90E

*whereA = single fastening or a single row parallel to grain with steel side platesB = single row parallel to grain with wood side plates or two rows parallel to grain not more than 127mm apart with a common wood splice plate, or multiple rows with separate wood or steel splice platesfor each rowC = all other arrangements†No data available for this condition.

10.2.2 Bolts, Lag Screws, Split Rings, and Shear Plate Connectors(General Requirements)

10.2.2.1 Inspection and TighteningStructures that have been assembled with unseasoned or partially seasoned lumber or timbers shall beinspected regularly at intervals not exceeding 6 months until it becomes apparent that further shrinkageof the wood will not be appreciable, and at each inspection the fastenings shall be tightened sufficientlyto bring the faces of the connected members into close contact without deformation.

10.2.2.2 AssemblyGrooves, daps, and holes shall be fabricated and oriented accurately in the contacting faces. Holes insteel plates shall be accurately placed to line up with holes in the adjoining wood and shall not be morethan 2 mm larger than the bolt or lag screw diameters.

10.2.2.3 Group of Fastenings

10.2.2.3.1A group of fastenings consists of one or more rows of fastenings of the same type and size arrangedsymmetrically with respect to the axis of the load.


102 August 2001

10.2.2.3.2A row of fastenings consists of one or more bolts, lag screws, or timber connector units of the same typeand size aligned with the direction of the load (see Figure 10.4.3).

10.2.2.3.3When fastenings in adjacent rows are staggered, and the distance between adjacent rows is less than 1/4the distance between the closest fastenings in adjacent rows measured parallel to the rows, the adjacentrows shall be considered as one row for purposes of determining the resistance of the group. For agroup of fastenings having an even number of rows, this principle shall apply to each pair. For a groupof fastenings having an odd number of rows, the more conservative interpretation shall apply.

10.2.2.3.4The modification factor, JG, for groups of timber connectors and lag screws is given in Tables 10.2.2.3.4Aand 10.2.2.3.4B.

10.2.2.3.5The modification factors, JG and JR, for groups of bolts are given in Clause 10.4.4.

10.2.2.4 Washers

10.2.2.4.1A standard cut washer or its equivalent (see Table 10.2.2.4.1) or a metal strap of the same thickness asthe washer shall be placed between the wood and the head and between the wood and the nut.

10.2.2.4.2When a bolt head or nut bears directly on a steel plate, washers may be omitted.

10.2.2.4.3All bolts or lag screws in axial tension or with a calculated tension component shall be provided withsteel plate washers, standard ogee washers, or malleable iron washers under heads and nuts. The area ofsuch washers shall be such that the bearing stress on the wood under the washer does not exceed thefactored resistance in compression perpendicular to grain. If steel washers are used, the thickness shallbe not less than one-tenth the diameter or one-tenth the length of the longer side of the washer.

10.2.2.5 Net Section

10.2.2.5.1Resistance of joints made using bolts, lag screws, and split ring and shear plate connectors shall bechecked for net section in accordance with Clause 4.3.8.

10.2.2.5.2For a bolted or lag screw joint under parallel-to-grain loading, staggered adjacent bolts or lag screwsshall be considered to be placed at the critical section unless their spacing centre-to-centre parallel tograin is more than eight bolt or lag screw shank diameters.

10.2.2.5.3For connector joints, the area deducted from the gross section shall include the projected area of thatportion of the connectors within the member and that portion of the bolt hole not within the connectorprojected area, located at the critical plane. Where connectors are staggered, adjacent connectors shallbe considered as occurring in the same critical transverse plane unless their spacing centre-to-centreparallel to grain is more than two connector diameters.

© C


esign in Wood

August 20011

03

Table 10.2.2.3.4AModification Factors, JG, for Timber Connector and Lag Screw Joints

with Wood Side Plates

Number of fasteners in a row

Arearatio*

The lesser of Am

or As† 2 3 4 5 6 7 8 9 10 11 12

0.5

< 8000 8 001–12 00012 001–18 00018 001–26 00026 001–42 000> 42 000

1.001.001.001.001.001.00

0.920.950.970.981.001.00

0.840.880.930.960.970.98

0.760.820.880.920.940.95

0.680.750.820.870.900.91

0.610.680.770.830.860.88

0.550.620.710.790.830.85

0.490.570.670.750.790.82

0.430.520.630.710.760.80

0.380.480.590.690.740.78

0.340.430.550.660.720.76

1.0

< 8 000 8 001–12 00012 001–18 00018 001–26 00026 001–42 000> 42 000

1.001.001.001.001.001.00

0.970.981.001.001.001.00

0.920.940.970.991.001.00

0.850.890.930.960.970.99

0.780.840.890.920.940.96

0.710.780.850.890.910.93

0.650.720.800.850.880.91

0.590.660.760.830.850.88

0.540.610.720.800.840.87

0.490.560.680.780.820.86

0.440.510.640.750.800.85

*Area ratio = the lesser of Am/As or As/Am

†Am = gross cross-sectional area of main member, mm2

As = sum of gross cross-sectional areas of side members, mm2

Note: For area ratios between 0.5 and 1.0, interpolate between tabulated values. For area ratios less than 0.5, extrapolate from tabulated values.

CAN

/CSA-O

86-01 © C


10

4August 2001

Table 10.2.2.3.4BModification Factors, JG, for Timber Connector and Lag Screw Joints with Steel Side Plates

ArearatioAm/As*

Number of fasteners in a row

Am 2 3 4 5 6 7 8 9 10 11 12

2–1216 000–26 00026 001–42 00042 001–76 00076 001–130 000

1.001.001.001.00

0.940.960.980.99

0.870.920.950.97

0.800.870.910.95

0.730.810.870.92

0.670.750.820.89

0.610.700.780.86

0.560.660.750.84

0.510.620.720.81

0.460.580.690.79

0.420.550.660.78

12–1826 001–42 00042 001–76 00076 001–130 000> 130 000

1.001.001.001.00

0.980.991.001.00

0.940.960.981.00

0.900.930.950.98

0.850.900.940.97

0.800.860.920.95

0.750.820.890.93

0.700.790.860.91

0.670.750.830.90

0.620.720.800.88

0.580.690.780.87

18–2426 001–42 00042 001–76 00076 001–130 000> 130 000

1.001.001.001.00

1.001.001.001.00

0.960.970.991.00

0.930.940.981.00

0.890.920.960.98

0.840.890.940.96

0.790.860.920.95

0.740.830.900.93

0.690.800.880.92

0.640.760.860.92

0.590.730.850.91

24–3026 001–42 00042 001–76 00076 001–130 000> 130 000

1.001.001.001.00

0.980.991.001.00

0.940.970.980.99

0.900.930.960.98

0.850.900.940.97

0.800.860.920.95

0.740.820.890.93

0.690.790.870.92

0.650.760.850.90

0.610.730.830.89

0.580.710.810.89

30–3526 001–42 00042 001–76 00076 001–130 000> 130 000

1.001.001.001.00

0.960.980.991.00

0.920.950.970.98

0.860.900.950.97

0.800.860.920.95

0.740.810.880.93

0.680.760.850.90

0.640.720.820.89

0.600.680.800.87

0.570.650.780.86

0.550.620.770.85

35–4226 001–42 00042 001–76 00076 001–130 000> 130 000

1.001.001.001.00

0.950.970.980.99

0.890.930.960.98

0.820.880.930.96

0.750.820.890.93

0.690.770.850.90

0.630.710.810.87

0.580.670.780.84

0.530.630.760.82

0.490.590.730.80

0.460.560.710.78

*Am = gross cross-sectional area of main member, mm2

As = sum of gross cross-sectional area of steel side plates, mm2

© C


esign in Wood

August 20011

05

Table 10.2.2.4.1Minimum Washer Sizes for Bolted, Lag Screw, and Timber Connector Joints

Bolted or lag screw joints Timber connector joints

Washer type Use

Rod orboltdiameter,dF, in

Outsidedimension,do, mm

Thickness,t, mm

2-1/2 in splitring with1/2 in bolt

4 in splitring with3/4 in bolt

2-5/8 in shearplate and 4 inshear platewith 3/4 in bolt*

t, mmdo,mm

t,mm

do,mm t, mm

do, mm

Standard cut(steel)

For bolts andlag screwsonly; too thinto resist anytensile loads

1/25/83/47/81

3545506065

34444

Cut washers not to be used with connectors

Square plate(steel)

For connectoror tensile load

1/25/83/47/81

6570758590

56698

3.2 50 4.8 75 6.4 75

Round plate(steel)

For any use,unless tensileloadingdevelopsenough stressto crush wood

1/23/47/8

657585

568

3.2 50 4.8 75 6.4 75

(Continued)

CAN

/CSA-O

86-01 © C


10

6August 2001

Table 10.2.2.4.1 (Concluded)

Bolted or lag screw joints Timber connector joints

Washertype Use

Rod orboltdiameter,dF, in

Outsidedimension,do, mm

Thickness,t, mm

2-1/2 in splitring with1/2 in bolt

4 in splitring with3/4 in bolt

2-5/8 in shearplate and 4inshear platewith 3/4 inbolt*

t,mm

do,mm

t,mm

do,mm

t,mm

do, mm

Ogee(cast iron)

Thicker and widerthan normal ormalleable ironwashers; forincreased stiffnessand bearingstrength

1/25/83/47/81

65 75 90100100

1316192225

3.2 55 4.8 75 6.4 75

Malleableiron

Wider thannormal washers;for addedbearing strength

1/25/83/47/81

65 70 75 90100

6 8111113

3.2 55 4.8 75 6.4 75

*For 4 in shear plates used with 7/8 in bolts, do is 90 mm.Note: Square or round plate bevelled washers may be necessary when bolts project at an angle to the wood.


August 2001 107

10.3 Split Ring and Shear Plate Connectors

10.3.1 General

10.3.1.1 Connector UnitFor purposes of specifying connector resistance herein, a connector unit shall consist of one of thefollowing, in any joint of any number of members:(a) one split ring connector with its bolt or lag screw;(b) one shear plate connector with its bolt or lag screw, used in conjunction with a steel strap or plate ina wood-to-metal joint; or(c) two shear plate connectors used back-to-back in the contact faces of a wood-to-wood joint with theirbolt or lag screw.

10.3.1.2 Split Ring ConnectorsTabulated resistances and design methods for split ring connectors given in Clause 10.3 are forconnectors whose dimensions are in accordance with Table 10.3.1A and that are manufactured fromhot-rolled carbon steel, SAE 1010, meeting the requirements of the SAE Handbook. Each ring shall forma closed true circle with the principal axis of the cross-section of the ring metal parallel to the geometricaxis of the ring. The ring shall be bevelled from the central portion toward the edges to a thickness lessthan that at midsection so that it will fit snugly in a precut groove, or such other means as to accomplishthe equivalent performance shall be used. It shall be cut through in one place in its circumference toform a tongue and slot.

10.3.1.3 Shear Plate ConnectorsTabulated resistances and design methods are for shear plate connectors whose dimensions are inaccordance with Table 10.3.1A and that conform to either of the following:(a) Pressed Steel Type: Pressed steel shear plates manufactured from hot-rolled carbon steel, SAE 1010,meeting the requirements of the SAE Handbook. Each plate shall be a true circle with a flange around theedge, extending at right angles to the face of the plate from one face only. The plate portion shall have acentral hole and two small perforations on diametrically opposite sides of the hole, each midway fromthe centre and circumference; or(b) Malleable Iron Type: Malleable iron shear plates manufactured in accordance with the requirementsof ASTM Standard A 47, Grade 32510 (or ASTM Standard A 47M, Grade 22010). Each casting shallconsist of a perforated round plate with a flange extending at right angles to the face of the plate andprojecting from one face only. The plate portion shall have a central bolt hole, reamed to size whererequired, with an integral hub concentric to the bolt hole and extending from the same face as theflange.

Table 10.3.1ATimber Connector Dimensions (mm)

Split ring 2-1/2 in 4 in

Inside diameter at centre when closedThickness of steel at centreDepth of steel

63.5 4.119.0

101.6 4.9 25.4

Shear plate

2-5/8 in 4 in

3/4 inbolt

7/8 inbolt

Diameter of plateDiameter of bolt holeThickness of plateDepth of flange

66.520.6 4.310.7

102.1 20.6 5.1 15.7

102.1 23.9 5.1 15.7


108 August 2001

A

B

C

DDE E

FG

H

I

Table 10.3.1BTimber Connector Groove Dimensions (mm)

Bolt hole diameterInside diameterWidthDepth

Shear plate groove

Split ring groove

4 in shear plate

A = 66.8B = —C = 20.6D = —E = 4.5F = 11.4G = 6.4H = —I = 57.2

102.439.423.824.65.3

16.35.6

12.788.6

102.439.420.624.65.3

16.35.6

12.788.6

20.6103.6

5.313.1

14.365.04.69.8

7/8 in bolt

3/4 inbolt

4 insplit ring

2-1/2 insplit ring

2-5/8 inshear plate

10.3.1.4 Connector GroovesDimensions of connector grooves and bolt hole sizes shall be in accordance with Table 10.3.1B.

10.3.2 Service Condition FactorThe service condition factors in Table 10.2.1.5 are based on the moisture content within a depth of20 mm from the connected surface.

10.3.3 Distance FactorsConnectors installed at any edge distance, end distance, or spacing less than the minimum for which atabulated value appears in the appropriate columns of Tables 10.3.3A to 10.3.3C shall not be consideredto provide resistance. Factors for reduction of resistance for edge distance, end distance, and spacingshall be separately determined, and the lowest factor so determined for any one connector shall beapplied to all connectors resisting a common force in a joint. (See Figures 10.3.3A and 10.3.3B.)


August 2001 109

Table 10.3.3AValues of JC for Timber Connector Edge Distance

Edgedistance,mm

2-1/2 in split ring or 2-5/8 in shear plate 4 in split ring or shear plate

2=15E 2=30E 2=45E to 90E 2=15E 2=30E 2=45E to 90E

45 50 55 60 65 70 75 80 85 90 95100

0.940.971.001.001.001.001.001.001.001.001.001.00

0.880.910.940.981.001.001.001.001.001.001.001.00

0.830.870.900.930.971.001.001.001.001.001.001.00

—————0.930.971.001.001.001.001.00

—————0.880.910.940.971.001.001.00

—————0.830.860.890.930.961.001.00

Notes:(1) At angle of load to grain 2=0E, the minimum edge distance for the particular connector size gives a value of JC = 1.00. For intermediate values of 2, linear interpolation may be used.(2) Values of JC apply to loaded edge distance only. Minimum edge distance for loaded or unloaded edge is 40 mm for 2-1/2 in split rings and 2-5/8 in shear plates, and 65 mm for 4 in split rings and shear plates.


110 August 2001

Table 10.3.3BValues of JC for Timber Connector End Distance

End distance, mm Tension

For members $130 mm thick

For members< 130 mm thick

2-1/2 in splitring or 2-5/8in shear plate

4 in splitring orshear plate

2 = 0E–90E 2 = 0E–90E

70 75 80 85 90 95100

105115120130135145150

0.620.650.680.700.730.760.78

————0.630.650.67

105110115120125130135140

160165175180190195205210

0.810.840.860.890.920.940.971.00

0.690.710.730.750.770.790.820.84

145150155160165170175180

220225235240250255265270

1.001.001.001.001.001.001.001.00

0.860.880.900.920.940.960.981.00

Notes:(1) Values of 2 shown are for angle of load to grain.(2) For connectors loaded in compression, JC = 1.00. Minimum end distances for connectorsloaded in compression are those given in the table for connectors loaded in tension.


August 2001 111

Table 10.3.3CTimber Connector Spacing (mm) for Values of JC between 0.75 and 1.0

Angle ofload tograin,2 E

Angle ofconnectorrow tograin,$ E

Minimum spacing between connectors measured centre-to-centre, mm

2-1/2 in split rings and2-5/8 in shear plates

4 in split rings and 4 in shear plates

JC=0.75 JC=1.00 JC=0.75 JC=1.00

0

15

30

45

60–90

0153045607590

0153045607590

0153045607590

0153045607590

0153045607590

90909090909090

90909090909090

90909090909090

90909090909090

90909090909090

170160135110100 90 90

150145130115105100 95

130125120110105100100

110110110110105105105

90 90 90100100105110

125125125125125125125

125125125125125125125

125125125125125125125

125125125125125125125

125125125125125125125

230215185155140130125

205195180160145135135

180175165155145145140

150150150150145145145

125125125135145150150

Note: Values of JC between 0.75 and 1.00 for intermediate connector spacings may be obtained by linearinterpolation.


112 August 2001

a

Load

Maintainedge distance

Legend:a = End distancedF = Connector diameter

dF

dF—4

C PieceL

C PieceL

as

s s

Load

Legend:a = End distanceeP = Unloaded edge distanceeQ = Loaded edge distances = Spacing

eP

eQ

Figure 10.3.3AEnd Distance for Member with Sloping End Cut

Figure 10.3.3BEnd Distance, Edge Distance, and Spacing


August 2001 113

10.3.4 Lumber ThicknessConnectors installed in lumber of a thickness less than the minimum specified in Table 10.3.4 for theconnector type and use shall not be considered to provide resistance.

Table 10.3.4Thickness Factor for Timber Connector, JT

Connector typeand size

Number of faces of apiece containingconnectors on a bolt

Thickness ofpiece, mm JT

2-1/2 in split ring 1 3825

1.000.85

2 5138

1.000.80

4 in split ring 1 3825

1.000.65

2 76 645138

1.00 0.950.800.65

2-5/8 in shear plate 1 645138

1.000.950.95

2 645138

1.000.950.75

4 in shear plate 1 4438

1.000.85

2 8976645144

1.000.950.850.750.65

10.3.5 Lag Screw Connector JointsWhen lag screws instead of bolts are used with connectors, the resistance shall vary uniformly withpenetration into the member receiving the point, from the full resistance for one connector unit withbolt for standard penetration to 0.75 times the full resistance for one connector unit with bolt forminimum penetration. Penetration shall be in accordance with Table 10.3.5 and shall be not less thanthe minimum value.


114 August 2001

Nr

PrQr

Prsin2θ Q

rcos2 θ

Table 10.3.5Penetration Factor, JP, for Split Rings

and Shear Plates Used with Lag Screws

Penetration of lag screw into member receiving point (number of shank diameters)

Connector Penetration

Species

DouglasFir-Larch Hem-Fir

Spruce-Pine-Fir

NorthernSpecies JP

2-1/2 insplit ring Standard 8 10 10 11 1.00

4 in splitring or 4 inshear plate* Minimum 3.5 4 4 4.5 0.75

2-5/8 inshear plate*

StandardMinimum

53.5

7 4

7 4

8 4.5

1.000.75

*When steel side plates are used with shear plates, use JP = 1.0.Note: For intermediate penetrations, linear interpolation may be used for values of JP between 0.75 and 1.00.

10.3.6 Lateral ResistanceThe factored lateral strength resistance of a split ring or shear plate connection, Pr, Qr, or Nr, determinedusing equations (a), (b), and (c), shall be greater than or equal to the effect of the factored loads. Thefactored strength resistance per shear plate unit shall not exceed the values in Table 10.3.6C:

(a) For parallel-to-grain loading

Pr = NPunFJF

(b) For perpendicular-to-grain loading

Qr = NQunFJF

(c) For loads at angle, 2, to grain

whereN = 0.6Pu = pu (KDKSFKT)pu = lateral strength resistance parallel to grain (Table 10.3.6A), kNJF = JGJCJTJOJPJG = factor for groups of fastenings (Tables 10.2.2.3.4A and 10.2.2.3.4B)JC = minimum configuration factor (Clause 10.3.3 and Tables 10.3.3A, 10.3.3.B, and 10.3.3C)JT = thickness factor (Table 10.3.4)JO = factor for connector orientation in grain

= 1.00 for side grain installation= 0.67 for end grain and all other installations

JP = factor for lag screw penetration (Clause 10.3.5 and Table 10.3.5)Qu = qu(KDKSFKT)qu = lateral strength resistance perpendicular to grain (Table 10.3.6B), kN


August 2001 115

Table 10.3.6ALateral Strength Resistance Parallel to Grain, pu,

of Timber Connector Unit (kN)

Split rings Shear plates

Species 2-1/2 in 4 in 2-5/8 in 4 in

Douglas Fir-LarchHem-FirSpruce-Pine-FirNorthern Species

31272321

55494542

27242322

49444240

Notes:(1) Resistances of 4 in shear plates are for plates with 3/4 in bolts. For plates with 7/8 inbolts, resistances may be increased by 25%.(2) Where wood side plates are used with 4 in shear plates, resistances are 90% of thetabulated resistances.

Table 10.3.6BLateral Strength Resistance Perpendicular to

Grain, qu, of Timber Connector Unit (kN)

Split rings Shear plates

Species 2-1/2 in 4 in 2-5/8 in 4 in

Douglas Fir-LarchHem-FirSpruce-Pine-FirNorthern Species

22181715

42353128

23191715

35282624

Table 10.3.6CMaximum Factored Strength Resistance

per Shear Plate Unit (kN)

Type of load2-5/8 in shearplate

4 in shearplate

3/4 in bolt 7/8 in bolt

Washers provided;no bearing on threadedportion of the bolt

When bearing may occur on thethreaded portion of the bolt

18

16

32

28

43

38

10.4 Bolts

10.4.1 General

10.4.1.1Design requirements and data in Clause 10.4 for bolted joints are based upon the use of boltsconforming to the requirements of ASTM Standard A 307. When bolts are used with steel side plates,the side plates shall conform to the requirements of CSA Standard G40.21 or ASTM Standard A 36.Note: Alternatively, bolted joints may be used where their design conforms to the requirements of Clause 3.3.2.


116 August 2001

10.4.1.2Bolt holes in wood shall be accurately aligned and drilled not less than 1.0 mm nor more than 2.0 mmlarger than the bolt diameter.

10.4.2 Member Thickness

10.4.2.1 Wood Side PlatesIn single and multiple shear connections, the member thickness in Clause 10.4.4.1 shall be that of thethinnest wood member.

10.4.2.2 Steel Side PlatesThe member thickness in Clause 10.4.4.1 shall be that of the thinnest wood member. Steel side platesshall be of adequate thickness to resist the applied load.

10.4.2.3 Wood to ConcreteWhen a connection consists of one wood member attached to concrete or masonry, the connection shallbe designed as a single shear connection utilizing the formulae in Clause 10.4.4. The wood membershall be considered the side member. The main member shall be assumed to have a thickness equal tothe penetration of the bolt in the concrete or masonry. A value of 125 MPa shall be assigned to f2. Theconcrete or masonry shall be of sufficient strength to resist the applied loads.

10.4.3 Placement of Bolts in Joints

10.4.3.1 Spacing of Bolts in a RowIn a row of bolts aligned with direction of load, regardless of direction of grain, and measured fromcentres of bolts (see Figure 10.4.3)(a) for parallel-to-grain loading: minimum spacings shall be four times the bolt diameter; and(b) for perpendicular-to-grain loading: spacing between bolts in a row perpendicular to grain shall belimited by the spacing requirements of the attached member or members (whether of wood loadedparallel to grain or of metal), but shall be not less than three diameters.

10.4.3.2 Row Spacing

10.4.3.2.1For parallel-to-grain loading, the spacing between rows shall be not less than twice the bolt diameter.

10.4.3.2.2For perpendicular-to-grain loading, the spacing between rows shall be at least 2-1/2 times the boltdiameter for a member thickness-to-diameter ratio of 2, and five times the bolt diameter for memberthickness-to-diameter ratios of 6 or more. For ratios between 2 and 6, the spacing shall be obtained bylinear interpolation.

10.4.3.2.3A single steel splice plate shall not be used for rows of bolts when the distance between the two outerrows exceeds 125 mm.


August 2001 117

Spacing in the row

Load

Load Perpendicularto Grain

Row spacing

Loaded edge distance

Spacing in the row

Load

Load Parallel to Grain

Row spacing

Edge distance

Edge distance

Loaded enddistance

Figure 10.4.3Placement of Bolts in Joints

10.4.3.3 End DistanceThe end distance shall be at least(a) seven times the bolt diameter or 50 mm, whichever is greater, for the loaded end; or(b) four times the bolt diameter or 50 mm, whichever is the greater, for the unloaded end.

10.4.3.4 Edge DistanceFor members loaded perpendicular to grain, the loaded edge distance shall be at least four times the bolt diameter, and the unloaded edge distance shall be at least 1-1/2 times the bolt diameter. For


118 August 2001

Nr

PrQr

Prsin2θ Q

rcos2θ

0.33l

d

0.5s

d

0.2

N 0.3,

members loaded parallel to grain, the edge distance shall be at least 1-1/2 times the bolt diameter, orhalf the distance between rows of bolts, whichever is greater.

10.4.4 Lateral Resistance

10.4.4.1The factored lateral strength resistance of a bolted connection, Pr, Qr, or Nr, varies directly with thenumber of shear planes and shall be greater than or equal to the effect of the factored loads:

(a) For parallel-to-grain loading

Pr = N PunsnFJF


Qr = NQunsnFJR

(c) for loads at angle, 2, to grain

whereN = 0.7Pu = pu(KDKSFKT)pu = lateral strength resistance for parallel to grain loading (Clause 10.4.4.2), Nns = number of shear planesJF = JGJLJRJG = factor for two to maximum 12 bolts in a row

but is not greater than 1.0

wherel = member thickness (see Clause 10.4.2), mms = bolt spacing in the row, mmd = bolt diameter, mmN = number of bolts in a rowNote: JG = 1.0 in cases with only one bolt per row, and in all wood-to-concrete connections.

JL = factor for loaded end distance = 0.75 for end distance of 7d, or 1.0 for 10d (for intermediate values, interpolate linearly)JR = factor for number of rows

= 1.0 for 1 row, or for 1 bolt per row= 0.8 for 2 rows (2 or more bolts in a row)= 0.6 for 3 rows (2 or more bolts in a row)

Qu = qu(KDKSFKT)qu = lateral strength resistance for perpendicular to grain loading (Clause 10.4.4.2), N

10.4.4.2The unit lateral strength resistances, pu or qu, (N per shear plane) shall be taken as the smallest valuedetermined from formulae (a) to (g) as follows: For two-member connections, only formulae (a), (b), (d), (e), (f), and (g), are valid. For three-memberconnections, only formulae (a), (c), (d), and (g) are valid.


August 2001 119

(a) F1d2 I1d—

(b) F1d2 f2

f1—

I2d—

(c) F1d2 f2

f1—

I2d—

12—

(d) F1d2+

1

5—

I1d—

1

6—

f2

(f1 + f2)fy

f1

—

(e) F1d2+

1

5—

I2d—

1

6—

f2

(f1 + f2)fy

f1

—

(f) F1d2+

I2d—

I1d—

1

5—

f2

f1

—

(g) F1d2 2

3—

f2

(f1 + f2)fy

f1

—

whereF1 = 0.8f1d = bolt diameter, mml1 = side member thickness, mmf2 = embedding strength of main member, MPal2 = main member thickness, mmf1 = embedding strength of side member, MPafy = bolt yield strength, MPa

= 310 MPa for ASTM A 307 bolts

For wood member embedding strength:

f = 63G (1–0.01d), for parallel-to-grain loading= 27.4G (1–0.01d), for perpendicular-to-grain loading

G = mean relative density (Table A10.1)


120 August 2001

For steel plate embedding strength:

f = 3.75 × (N steel /N wood) × Fu

N steel = resistance factor for steel member in bolted connection= 0.67

N wood = resistance factor for wood member in bolted connection = 0.7

Fu = ultimate tensile strength of steel= 400 MPa for ASTM A 36 steel= 450 MPa for G40.21M steel, grades 300W and 350W

10.4.5 Combined Lateral and Axial ResistanceResistances are for loading acting perpendicular to the axis of a bolt. Connections shall also be ofadequate size to resist the component parallel to the bolt axis. Washers or plates of adequate thicknessand size to resist the factored load component parallel to the axis of the bolt shall be installed.

10.5 Drift Pins

10.5.1 GeneralDesign requirements for drift pin joints are based on round mild steel bolt stock, 16–25 mm diameter, inaccordance with ASTM Standard A 307 or CSA Standard G40.21.

10.5.2 Prebored HolesHoles in timber shall be prebored not less than 0.8 mm nor more than 1 mm smaller than the drift pindiameter.

10.5.3 Drift Pin PointsThe leading end of drift pins shall be chisel-pointed, conically tapered, hemispherical or otherwiseshaped to permit driving into prebored holes with minimum damage to the wood.

10.5.4 Drift Pin Length

10.5.4.1Length of drift pins shall be equal to the sum of the depths of two superimposed members to beconnected less 15 mm, and each drift pin shall be considered to give one shear plane. Figure 10.5.5shows a typical drift pin connection in timber cribwork.

10.5.4.2Drift pin joints shall be used only where gravity or mechanical restraint prevents axial tension stress inthe drift pins.

10.5.5 Size and Placement of Drift Pins in Joints

10.5.5.1Pin diameter shall not be greater than 1/10 of the width of the timbers to be connected.

10.5.5.2End and edge distance shall be at least 2-1/2 times the pin diameter.

10.5.5.3Spacing between pins in a row and between rows of pins shall be at least four times the pin diameter.


August 2001 121

Nr

PrQr

Prsin2θ Q

rcos2θ

15 mm

15 mm

Limits ofpenetration

Max. driftpin length

Depth of member

Drift pins drivenon opposite diagonalin layer below

10.5.6 Lateral ResistanceThe factored lateral strength of a drift pin connection, Pr, Qr, or Nr, shall be greater than or equal to theeffect of the factored loads:(a) for parallel-to-grain loading

Pr = N(0.6Pu)nF

(b) for perpendicular-to-grain loading

Qr = N(0.6Qu)nF

(c) for loads at angle, 2, to grain

whereN = 0.7Pu = pu(KDKSFKT)pu = lateral strength resistance for parallel-to-grain loading for bolts (Clause 10.4.4.2), NQu = qu(KDKSFKT)qu = lateral strength resistance for perpendicular-to-grain loading for bolts (Clause 10.4.4.2), N

At any shear plane between two overlapping timbers, as shown in Figure 10.5.5, only two pins shall becounted as resisting the shear force.

Figure 10.5.5Placement of Drift Pins


122 August 2001

10.6 Lag Screws

10.6.1 General

10.6.1.1Design requirements in Clause 10.6 for lag screw joints are based upon the use of lag screws of materialconforming to the requirements of ANSI/ASME Standard B18.2.1.10.6.1.2For purposes of specifying resistances of lag screw joints, values tabulated in this Standard shall apply toone lag screw either in withdrawal or in lateral resistance in a two-member joint.

10.6.2 Placement of Lag Screws in Joints

10.6.2.1Lag screw holes shall be in accordance with the following:(a) the lead hole for the shank shall have the same diameter as the shank and the same depth as thelength as the unthreaded shank; and(b) the lead hole for the threaded portion shall have a diameter equal to 65–85% of the shank diameterfor dense hardwoods, 60–75% of the shank diameter for Douglas Fir-Larch species, and 40–70% of theshank diameter for less dense species. The larger percentage figure in each range shall apply to screws ofthe greater diameters. The length of the lead hole shall be at least equal to the length of the threadedportion.

10.6.2.2The threaded portion of the screw shall be inserted in its lead hole by turning with a wrench, not bydriving.

10.6.2.3Soap or other lubricant, not petroleum based, may be used on the screws or in the lead hole to facilitateinsertion and prevent damage to the screw.

10.6.2.4The spacings, end distances, edge distances, and net section for lag screw joints shall be the same as forjoints with bolts of a diameter equal to the shank diameter of the lag screw used (see Clause 10.4.2).

10.6.3 Penetration of Lag Screws

10.6.3.1In determining the penetration of a lag screw into a member, the reduced point shall not be considereda part of the threaded portion.

10.6.3.2The maximum lengths of penetration used in determination of lateral resistance are(a) for Douglas Fir-Larch, nine times shank diameter;(b) for Hem-Fir, 10 times shank diameter; and(c) for S-P-F and Northern Species, 11 times shank diameter.

10.6.3.3For lag screws loaded laterally, the minimum length of penetration into the main member (l2 inClause 10.6.6.1.2) shall be no less than five times the shank diameter, d.


August 2001 123

10.6.4 Side Members

10.6.4.1 Wood Side PlatesThickness of wood side plates shall be at least twice the shank diameter of the lag screw.

10.6.4.2 Steel Side PlatesThe stresses induced in the steel side plate and at the bearing of the lag screw on the plate shall notexceed the resistance of the steel used.

10.6.5 Withdrawal ResistanceThe factored withdrawal resistance, Prw, of a group of lag screws in a connection shall be greater than orequal to the effect of the factored loads:

Prw = NYwLtnFJE

whereN = 0.6Yw = yw(KDKSFKT)yw = basic withdrawal resistance per millimetre of penetration (Table 10.6.5.1), N/mmLt = length of penetration of threaded portion of lag screw in main member (Clause 10.6.3), mmJE = end grain factor for lag screws

= 0.75 in end grain, or= 1.00 for all other cases

Note: Use of lag screws in end grain should be avoided whenever possible.

Table 10.6.5.1Basic Withdrawal Resistance for Lag Screws, yw (N/mm)

Species group

Shank diameter, in

1/4 5/16 3/8 7/16 1/2 5/8 3/4 7/8 1

Douglas Fir-LarchHem-FirS-P-FNorthern Species

74373127

97554242

120 70 61 58

140 86 75 70

170100 91 84

200130120110

240150140130

280180170150

310200190180


10.6.6.1 Side Grain

10.6.6.1.1The factored lateral strength resistance of a lag screw connection, Pr, Qr, or Nr, shall be greater than orequal to the effect of the factored loads:(a) For parallel-to-grain loading

Pr = NPunFJGJPL


Qr = NQunFJGJPL


124 August 2001

Nr

PrQr

Prsin2θ Q

rcos2θ

(a) F1d2 I1d—

(b) F1d2 f2

f1—

I2d—

(c) F1d2+

1

5—

I1d—

1

6—

f2

(f1 + f2)fy

f1

—

(d) F1d2+

1

5—

I2d—

1

6—

f2

(f1 + f2)fy

f1

—

(e) F1d2+

I2d—

I1d—

1

5—

f2

f1

—

(f) F1d2 2

3—

f2

(f1 + f2)fy

f1

—

(c) For loads at angle, 2, to grain

whereN = 0.6Pu = pu(KDKSFKT)pu = lateral strength resistance for parallel-to-grain loading, N (Clause 10.6.6.1.2)JG = factor for groups of fastenings (Tables 10.2.2.3.4A and 10.2.2.3.4B)JPL = factor for reduced penetration

= 0.625 for penetration of 5d and 1.0 for 8d (for intermediate values, interpolate linearly)Qu = qu(KDKSFKT)qu = lateral strength resistance for perpendicular-to-grain loading, N (Clause 10.6.6.1.2)

10.6.6.1.2The unit lateral strength resistances, pu or qu, shall be taken as the smallest value determined fromformulae (a) to (f) as follows:

whereF1 = 0.8f1d = lag screw diameter, mm


August 2001 125

f2 = embedding strength of main member, MPa= 63G(1–0.01d) for parallel-to-grain loading= 27.4G(1–0.01d) for perpendicular-to-grain loading

G = mean relative density (Table A10.1)l2 = length of penetration into main member, mm (Clause 10.6.3)fy = lag screw yield strength, MPa

= 480 MPa for 1/4 in diameter lag screws= 410 MPa for 5/16 in diameter lag screws= 310 MPa for 3/8 in or greater diameter lag screws

For wood side plates:

f1 = embedding strength of side member, MPa= 63G(1–0.01d) for parallel-to-grain loading= 27.4G(1–0.01d) for perpendicular-to-grain loading

l1 = side member thickness, mm (Clause 10.6.4.1)

For steel side plates:

f1 = embedding strength of steel side plate, MPa= 3.75 × (N steel / N wood) x Fu

N steel = resistance factor for steel member in lag screw connection= 0.67

N wood = resistance factor for wood member in lag screw connection= 0.60

Fu = ultimate tensile strength of steel= 400 MPa for ASTM A 36 steel= 450 MPa for CSA-G40.21M steel, grades 300W and 350W

l1 = side plate thickness, mm

10.6.6.2 End GrainLateral resistance of lag screws inserted parallel to grain in the end grain of the main member shall be nogreater than 2/3 of the lateral side grain resistance for perpendicular to grain if wood side plates areused. If steel side plates are used, lateral resistance shall be no greater than 1/2 of the lateral side grainresistance for perpendicular-to-grain loading in the main member.

10.6.6.3 Joint DeformationWhere the lateral deformation of lag screw joints is required for design, joint deformation may beestimated in accordance with Clause A10.6.6.3.

10.7 Timber Rivets (also known as Glulam Rivets)

10.7.1 General

10.7.1.1Design methods and tabulated resistances given in Clause 10.7 are for timber rivets manufactured tohave the properties shown below and used with steel side plates conforming to CSA Standard G40.21 orASTM Standard A 36, and whose dimensions conform to Figure 10.7.1.1.


126 August 2001

3.18 ± 0.12 mm5.59 ± 0.25 mm

8.76 ± 0.25 mm

L = Rivet length

Lp = Penetration

6.4 ± 0.8 mm

3.2 mm minimum

6.4 mm

3.2 mm

6.4 ± 0.2 mm

eS = 12 mm minimum

eS = 12 mmminimum

Grain

SP = 25 mmminimum

SQ = 15 mm minimum

Notes:(1) Hole diameter: 6.7 mm minimum to 7.0 mm maximum.(2) Tolerance in location of holes: 3 mm maximum in any direction.(3) Orient wide face of rivets parallel to grain, regardless of plate orientation.(4) All dimensions are prior to galvanizing, in millimetres.

Hardness Ultimate tensile strength Finish Rockwell C32-39 1000 MPa, minimum Hot-dip galvanized

Figure 10.7.1.1Steel Side Plates for Timber Rivets

10.7.1.2For wet service conditions, side plates shall be hot-dip galvanized.

10.7.1.3Design criteria for timber rivet joints apply to timber rivets that satisfy the requirements ofClause 10.7.1.1 loaded in single shear or in withdrawal, with steel side plates, on Douglas Fir-Larch orSpruce-Lodgepole Pine-Jack Pine glued-laminated timber manufactured in accordance with CSAStandard CAN/CSA-O122, or on sawn lumber of 64 mm minimum thickness.

10.7.1.4Side plates shall be of adequate cross-section to resist tension and compression forces, as well as bucklingat critical sections, but shall be not less than 3.2 mm in thickness.


August 2001 127

10.7.1.5Each rivet shall, in all cases, be placed with its major cross-sectional dimension aligned parallel to thegrain. Design criteria are based on rivets driven through circular holes in the side plates until the conicalheads are firmly seated, but rivets shall not be driven flush. Note: Timber rivets at the perimeter of the group should be driven first. Successive timber rivets should be driven in aspiral pattern from the outside to the centre of the group.

10.7.1.6Minimum spacing of rivets shall be 15 mm perpendicular to the grain and 25 mm parallel to the grain.

10.7.1.7Minimum values for end and edge distance, as shown and noted in Figure 10.7.1.7, are listed inTable 10.7.1.7.

10.7.1.8The maximum penetration of any rivet shall be 70% of the thickness of the wood member, whetherdriven on two faces or one face only. Except as permitted by Clause 10.7.1.9 for joints with rivets drivenfrom opposite faces of a wood member, the rivet length shall be such that the points do not overlap.

Table 10.7.1.7Minimum End and Edge Distances for Timber Rivet Joints

Number ofrivet rows,nR

Minimum end distance, a, mm Minimum edge distance, e, mm

Loadparallelto grain

Loadperpendicularto grain

Free edge,eP

Loaded edge,eQ

1, 23–89, 1011, 1213, 1415, 1617 and greater

75 75100125150175200

50 75 80100120140160

25252525252525

50505050505050

Note: End and edge distances are shown in Figure 10.7.1.7.


128 August 2001

eS

eS

a

Rivet rows SteelplatesP

eP

Lp

b/2b/2

LpSQ

SP

eP

Load parallel to grain

Rivet rowsQ

a

eS

eS

eQ

eP

SQ

SP

Steelplates

Lp

b/2b/2

Lp

Load perpendicular to grain

Rivet rows N

SQ

SPa

eP

eQ

Steel plates

Load at angle to grain

Figure 10.7.1.7End and Edge Distances for Timber Rivet Joints


August 2001 129

10.7.1.9For joints where rivets are driven from opposite faces of a wood member such that their points overlap,the minimum spacing requirements of Clause 10.7.1.6 shall apply to the distance between the rivets attheir points. The total lateral resistance of the connection shall be calculated in accordance withClause 10.7.2, considering the connection to be a one-sided timber rivet joint, with(a) the number of rivets associated with the one plate equalling the total number of rivets at the joint;and(b) Sp and SQ determined as the distances between the rivets at their points.

10.7.1.10For wet fabrication conditions in sawn lumber, the maximum dimension perpendicular to grain overwhich a rivet group spans shall not exceed 200 mm.


10.7.2.1A timber rivet joint (one plate and the rivets associated with it) in side grain shall be designed such thatthe factored lateral strength resistance of the joint is greater than or equal to the effect of the factoredloads. Design of timber rivets loaded laterally is governed by either the ductile failure of the rivet or thebrittle failure of the wood.

10.7.2.2For loading parallel to grain, the factored lateral strength resistance, Pr, of the joint shall be

Pr = NPuH

where N = 0.6Pu = lateral resistance parallel to grain (Clause 10.7.2.3), kNH = material factor

= 1.00 for Douglas Fir-Larch glulam= 0.80 for Spruce-Lodgepole Pine-Jack Pine glulam= 0.50 for Douglas Fir-Larch sawn timber= 0.45 for Hem-Fir sawn timber= 0.40 for Spruce-Pine-Fir sawn timber= 0.35 for Northern Species sawn timber

10.7.2.3The unit capacity per rivet joint parallel to grain, Pu, shall be calculated as the lesser of Py or Pw, as follows:(a) Py = (1.09Lp

0.32nRnC)JYKSFKT for rivet capacity

and

(b) Pw = pwKDKSFKT for wood capacity

whereLp = length of penetration ( = overall rivet length – plate thickness – 3.2), mm (Figure 10.7.1.1)nR = number of rows of rivets parallel to direction of loadnC = number of rivets per rowJY = side plate factor

= 1.00 for side plate thickness of 6.3 mm and more= 0.90 for side plate thickness between 4.7 and 6.3 mm= 0.80 for side plate thickness between 3.2 and 4.7 mm


130 August 2001

Nr

PrQr

Prsin2θ Q

rcos2θ

pw = lateral resistance parallel to grain (Table 10.7.2.3), kN, using wood memberthickness for the member dimension in Table 10.7.2.3 for connections withsteel plates on opposite sides, and using twice the wood member thickness for themember dimension in Table 10.7.2.3 for connections having only one plate

Note: As an alternative, pw may be calculated in accordance with Clause A10.7.2.3.

10.7.2.4For loading perpendicular to grain, the factored lateral strength resistance, Qr, of the joint shall be

Qr = NQuH

whereN = 0.6Qu = lateral resistance perpendicular to grain (Clause 10.7.2.5), kNH = material factor (Clause 10.7.2.2)

10.7.2.5The unit capacity per rivet joint perpendicular to grain, Qu, shall be calculated as the lesser of Qy or Qw,as follows:(a) Qy = (0.62Lp

0.32nRnC)JYKSFKT for rivet capacity

and

(b) Qw = (qwLp0.8Ct)KDKSFKT for wood capacity

whereLp,nR,nC,JY = variables specified in Clause 10.7.2.3qw = value determined from Table 10.7.2.5A, kNCt = factor determined from Table 10.7.2.5BNote: As an alternative, qw and Ct may be calculated in accordance with Clause A10.7.2.3.

10.7.2.6For loading at an angle to the grain, 2, the factored lateral resistance of the joint, Nr, shall be calculatedfrom

wherePr = value determined in accordance with Clause 10.7.2.2Qr = value determined in accordance with Clause 10.7.2.4

10.7.2.7When timber rivets are used in end grain, the factored lateral resistance of the joint shall be 50% of thatfor loading perpendicular to grain. When used in intermediate grain, the factored lateral resistance maybe increased linearly from the value calculated for end grain, up to 100% of the applicable parallel orperpendicular to side grain value.

10.7.3 Withdrawal Resistance

10.7.3.1The use of timber rivets loaded in withdrawal shall be permitted only for dry service conditions for short-term and standard-term load durations.


August 2001 131

10.7.3.2The factored withdrawal resistance from the side grain, Prw, of a timber rivet joint shall be greater than orequal to the effect of the factored loads

Prw = NYwLpnRnC

whereN = 0.6Yw = yw(KSFKT)yw = withdrawal resistance per millimetre of penetration, N/mm

= 13 N/mm for glulam= 7 N/mm for sawn timber

Lp,nR,nC = variables specified in Clause 10.7.2.3


132 August 2001

Table 10.7.2.3Values of pw (kN), Parallel to Grain for Timber Rivet Joints

40 mm rivets. Spacing: Sp = 25 mm; SQ = 25 mm

Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10 2 14 16 18 20

80

2 4 6 8101214161820

24 35 46 58 68 76 84 88 98104

56 74 92108125140155170185205

88110135160180205220245270280

125155185215245270300320350370

160200240270310340370410430460

195240280320370400440480510540

225270320370410450490530570600

260310360410460510560600640680

290350410460510570630680730770

330390460520580640710770810850

130

2 4 6 8101214161820

31 44 60 76 88100108114125135

62 80 98116135150170185200220

72 92112130150170185205225240

88108130150175195215235250270

112135165190215240260290310330

130160190215245270300330350380

150180215245270300330360390420

180215250280310350380410450490

235260310340370410450500540590

290310360390440480520580610660

175

2 4 6 8101214161820

34 50 66 84 98110120125140150

58 74 90108125140155170185205

66 84102120140155175190205225

80100120140160180200215235250

104125150175200220245270290310

120150175200225250280300330350

140170200225250280310330360390

170200235260290330360390420460

215245280310350390420460510550

270290330360410450490540570620

215andgreater

2 4 6 8101214161820

34 50 66 84 98110120125140150

56 72 90106120135155170185200

66 84100118135155170185200220

80 98118140155175195210230245

102125150170195215240260280300

118145170195225250270300320350

135165195225250270300330360390

165195230260290320350380410450

215240280310340380410460500540

270290320350400440480530560610

(See notes at end of Table.) (Continued)


August 2001 133

Table 10.7.2.3 (Continued)


Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

80

2 4 6 8101214161820

27 40 52 66 76 86 94100110118

64 86106125145160180195215235

100125155185210235250280310330

140175215245280310340370400420

185225270310350390420460490520

225280330370420460510550590620

260320370430480530580620670710

300360410470530590640700740790

340 400 470 520 590 650 720 780 830 870

380 450 530 590 660 730 810 880 930 970

130

2 4 6 8101214161820

35 50 68 86100112125130145150

66 94120150175200225250270290

82118150180210240270300320350

106150185225260290320360390420

145205250300350390430480520560

180250310370420480530580630680

225310380450510560620680750810

290380470540610690760830910990

390 500 610 680 760 840 930101010901140

490 590 690 770 860 9501050114012101270

175

2 4 6 8101214161820

39 56 76 96110125135145160170

60 88114140160185210230250270

76110140170195225250280300330

98135175205240270300330360390

135190235280320360400440480520

170235290340390440490540580630

205280350410470520580630700760

260350440500570640710770850920

360 470 570 650 730 810 900 99010901190

480 590 710 790 91010101110123013101400

215andgreater

2 4 6 8101214161820

39 56 76 96110125135145160170

60 86112135160180205225250270

74108135165190220245270290320

96135170205235260300320360380

130185235280320360400430470510

165230290340380440480530570620

205280350410470510570620680740

260350430500560630700760830910

360 460 560 640 710 800 880 98010801170

480 580 700 780 89010001090121012901410



134 August 2001



Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10

80

2 4 6 8101214161820

21313946546270788692

34 44 54 64 74 84 94104114125

48 60 74 88102116130140155165

68 86104120140155170190205220

92114140160180205225245260290

130

2 4 6 8101214161820

24313946546270788694

34 42 54 64 74 84 94104114125

46 60 74 88100114125140150165

66 82 98116130145165180195210

86106130150170186205225245260

175andgreater

2 4 6 8101214161820

24313946546270788694

34 42 54 64 74 84 94104114125

46 60 74 86100112125140150160

64 80 96114130145160175190205

84104125145165180200220235250



August 2001 135

Table 10.7.2.3 (Continued)65 mm rivets. Spacing: Sp = 25 mm; SQ = 25 mm

Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

130

2 4 6 8101214161820

27 39 52 66 76 86 94 98110116

64 84104120140155175195210230

98125150180205230250280300320

140175210245280310340360390420

180225270310350390420460490520

220270320360410450500540570610

250310360410460510560600650680

290350410460520570630680720770

330390460520580640710770820860

370440520580650720800860920960

175

2 4 6 8101214161820

31 44 60 76 88100110114125135

74 96120140165180205225245270

114145175210240270290320350370

160200240270300320350370400420

210260300330360390420450470500

250310340370410440470500530560

300350390420450480510540580610

340400440480510550590620660700

380460530560600640680730790830

430520600640690740780840870930

215

2 4 6 8101214161820

35 50 68 86100112120130145150

82108135160185205225245270280

125150170195215240260280290310

160180200225245270290310330350

205220250280300320350370390420

235260280310340370390420440470

270290320350370400430450480510

320330370390420460490520550590

410410440470500540570610660700

490480510530580620650710730780

265

2 4 6 8101214161820

39 56 76 96110125135145160170

90112135155175195215230250260

118135160180200215235250270290

145160185205225245260280300320

185200225250270300320340360380

215235260280310330360380400430

245260290310340360390410440470

290300340360390420450470510540

370370400430460490520560600640

460440470480530570600650670720

315andgreater

2 4 6 8101214161820

40 60 80100116130145150170175

88110130150170185205220240250

114130155170190205225240260270

140155175195215230250270290300

180195215240260280300320340360

205225245270290320340360380410

235250280300320350370390420450

280290320340370400430450480520

360360380410430470500540580620

450420440460500540570620640690



136 August 2001


Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

130

2 4 6 8101214161820

31 44 60 74 86 98108112125130

72 96120140160180200220240260

114145175205235260290320350370

160200240280310350390420450480

205260310350390440480520560590

250310370420480520580620670700

300360420480540600650700760800

340 400 470 530 600 660 720 790 840 890

380 450 530 590 660 730 810 880 940 990

430 510 600 670 750 830 910 99010501100

175

2 4 6 8101214161820

35 52 68 86100114125130145155

84112140165190210235260280310

130165205240270310330370400430

185230280320360410450480520550

240300350410460510560600650680

300360430490560660670730770820

350420490560630700760810880930

390 470 540 620 690 770 840 910 9701030

440 520 610 690 770 850 940102010901150

500 590 690 780 870 9601060115012201270

215

2 4 6 8101214161820

40 58 76 98112125140145160170

94125155185210235260290310340

140185220260290320350380400430

185230270310340380410440470500

250310360410450490540570610650

310380440490540590640690730780

380450530590640690750800860910

440 520 610 690 770 840 900 96010301100

490 590 690 770 860 9501050114012301290

560 660 780 870 97010801190129013701430

265

2 4 6 8101214161820

44 64 86108125140155165180190

94130160190220245270290320340

130170205235260290320340370390

170210245280310340370400430460

230280330370420450490530560600

280350400450500540590630670710

350410480540590630690730790840

440 510 590 650 710 770 830 880 9501020

550 650 760 820 890 9701040113012101300

620 740 860 970108011901270138014501550

315andgreater

2 4 6 8101214161820

46 68 90114130150165170190200

92125160185210235260280310330

125165195225250280300330350370

160200240270300330360380410430

220270320360400430470500530570

270330390430480520560600640680

330400470520570610650700750800

420 490 570 620 680 740 790 840 910 970

580 640 730 790 860 9301000108011601240

650 780 900 960106011501230134013901490



August 2001 137



Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10

130

2 4 6 8101214161820

24 34 42 50 58 66 76 84 92100

36 46 58 68 80 90102112125135

50 66 80 94110125140150165180

72 92110130150165185200220240

100125150175195220240260280310

175andgreater

2 4 6 8101214161820

26 34 42 50 58 66 76 84 92100

36 46 58 68 80 90102112125135

50 66 80 94110125135150165180

72 92110130150165185200220235

100125150170195215240260280310



138 August 2001


Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

175

2 4 6 8101214161820

28 40 54 68 80 90 98104114120

66 86108125145165180200220240

102130160190215240260290310340

145180220250290320350380410430

190235280320360400440480510540

230280330380430470520560600630

270320380430480540580620670710

300360420480540600650710760810

350410480540600670740800860900

390 460 540 610 680 750 830 900 9601000

215

2 4 6 8101214161820

31 44 60 76 88 98108114125135

72 96118140160180200220240260

114145175205235260290320340370

160200240280320350390420450480

210260310350400440480520560590

250310370420470520570620660690

290350410470530590640690740780

330400470530590660720780830890

380450530590660730810880950990

430 510 600 670 750 830 910 99010501100

265

2 4 6 8101214161820

34 50 66 84 98110120125140150

80106130155180200225245270290

125160195230260290320350380410

180225270310350390410430440460

235290340390440470490500520540

280340410470500520540550570590

330390460530550550570590610640

370450520590610630650660690720

420500590660700720740780810850

480 570 670 750 800 820 840 880 890 930

315

2 4 6 8101214161820

38 54 74 94108120135140155165

90118145170200220245270300320

140175215250280310320340360370

195245300320330340360370390400

260320380390400410420440450470

310380420430440450470480490510

360430470470470480500510530560

410490530520530540560580600630

470560630610610630650680710740

530 630 720 680 700 720 730 770 780 820

365andgreater

2 4 6 8101214161820

40 60 80100116130145150165175

96125155180205230250280300310

150190225250270290310320330350

210270290300310320340350360370

280340360360370380400410420440

330410400400410420440450460480

390450440430440450460480500520

450520500490490510520540560590

510600590570570590600630670700

570 680 670 640 650 670 690 720 740 770



August 2001 139


Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

175

2 4 6 8101214161820

32 46 62 78 90102112118130140

76100125145170190210230250280

118150180215245270300330360390

165205250290330370400430470500

215270320370410460500540580610

270330390440500550600650700730

310 380 440 510 560 630 680 730 790 830

350 420 490 550 620 690 750 820 870 930

390 470 550 620 690 760 840 910 9801030

450 530 620 700 780 860 950103010901150

215

2 4 6 8101214161820

35 50 68 86100112120130145150

84110135160185205230250280300

130165200240270300330360400420

180230270320360400440480510540

235290350400450500550600640670

290360430480550600660720760810

340 410 490 560 620 690 750 800 870 910

390 460 540 610 680 760 830 900 9601020

430 520 600 680 760 840 930100010801130

490 580 680 770 860 9501050113012001260

265

2 4 6 8101214161820

39 56 76 96110125135145160170

94125150180210230260280310340

145185225260300340370410440470

205250310350400450500530570600

260330390450510560610670710750

330400470540610670740800850900

380 460 540 620 690 770 840 900 9701020

430 510 600 680 760 850 930101010701140

480 580 670 760 850 9401030112012101260

550 650 760 860 96010601170127013401410

315

2 4 6 8101214161820

42 62 84106120140150160175185

102135170200230250280310340370

160205245290330370400420440460

225280340390420440460480500520

290360430490540560590610640670

360440520600630660700720750790

420 510 600 680 740 760 790 830 870 920

470 570 660 750 840 910 950 99010401100

530 630 740 830 93010301140124013201390

600 720 840 940105011701290140014801550

365andgreater

2 4 6 8101214161820

46 68 90114130150165170190200

102145180215250270310340360380

175220270310340360380400410430

240300350370390410430450470490

310390460480500530550580600630

390480550560590620650680700740

460 550 640 660 690 710 750 780 820 860

510 610 710 780 810 850 890 930 9801030

580 690 800 900101010601100117012401310

650 780 9101020114012601340143014701550



140 August 2001

Table 10.7.2.3 (Concluded)


Memberdimension,*mm

Rivetsper row,nC

Number of rows, nR

2 4 6 8 10

175andgreater

2 4 6 8101214161820

25 34 42 50 60 68 76 84 94102

36 46 58 70 80 92102114125135

52 66 80 96110125140155165180

74 92112130150170185205225240

100125150175200220245270290310

*Member dimension is identified as “b” in Figure 10.7.1.7 for connections with steel plates on opposite sides. Forconnections having only one plate, member dimension is twice the thickness of the wood member.Note: For intermediate sawn lumber dimensions, interpolation may be used.


August 2001 141

Table 10.7.2.5AValues of qw (kN), Perpendicular to Grain for Timber Rivet Joints

Spacing: Sp = 25 mm

SQ

Rivetsper row,nC

Number of rows, nR

1 2 3 4 5 6 8 10

15

2 3 4 5 6 7 8 910111213141516171820

0.570.570.600.630.710.770.860.910.971.051.141.261.421.501.611.731.881.84

0.570.570.600.630.710.770.860.910.971.051.141.261.421.501.611.731.881.84

0.610.610.650.690.760.820.900.971.051.121.211.291.401.501.621.721.851.91

0.610.630.660.700.770.820.900.971.061.131.211.291.371.471.601.691.801.91

0.670.660.710.750.810.870.941.011.101.171.241.331.421.501.601.691.801.93

0.710.700.740.780.840.890.961.031.121.181.251.331.441.501.581.671.771.93

0.840.820.850.890.951.001.071.131.211.281.381.451.541.621.711.791.872.08

0.970.930.950.991.061.111.181.251.351.431.521.591.681.781.891.962.042.24

25

2 3 4 5 6 7 8 910111213141516171820

0.670.660.700.730.820.901.011.061.131.221.331.471.651.751.872.022.192.14

0.670.660.700.730.820.901.011.061.131.221.331.471.651.751.872.022.192.14

0.700.700.750.800.870.941.041.111.201.291.391.481.611.721.861.972.122.19

0.690.720.750.790.860.931.021.101.201.281.371.451.551.661.801.912.032.15

0.750.740.800.840.910.971.061.141.241.301.391.481.591.681.791.892.012.17

0.790.780.830.870.941.001.081.151.251.321.401.491.611.681.771.871.982.16

0.930.910.940.981.051.111.191.261.341.431.531.611.711.801.901.982.082.31

1.081.031.061.101.181.231.311.391.501.591.691.771.861.972.102.182.272.49

40

2 3 4 5 6 7 8 910111213141516171820

0.960.951.021.061.191.301.451.531.631.761.922.122.392.532.702.913.173.10

0.960.951.021.061.191.301.451.531.631.761.922.122.392.532.702.913.173.10

0.980.981.051.111.221.321.451.551.691.801.942.082.252.412.612.762.973.07

0.930.961.001.061.161.241.361.471.601.711.831.942.072.222.412.552.722.88

0.980.981.051.111.201.281.401.501.631.721.841.962.102.222.362.492.662.86

1.031.021.071.131.221.301.401.501.631.711.821.942.092.192.302.432.582.80

1.201.161.211.261.351.431.531.611.721.831.962.072.202.312.442.542.662.96

1.381.321.361.411.511.581.681.791.932.042.172.272.392.532.692.792.913.19


142 August 2001

Table 10.7.2.5BValues of Factor Ct

ep (nC–1)SQ Ct

ep (nC–1)SQ Ct

0.10.20.30.40.50.60.70.80.91.01.21.41.61.82.02.42.8

5.763.192.362.001.771.611.471.361.281.201.101.020.960.920.890.850.81

3.23.64.05.06.07.08.09.0

10.012.014.016.018.020.025.030.0

0.790.770.760.720.700.680.660.640.630.610.590.570.560.550.530.51

10.8 Truss Plates

10.8.1 General

10.8.1.1Design requirements in Clause 10.8 for truss plate joints are for light-gauge metal plates that dependupon extended teeth or nails embedded into the wood to transfer load and that conform to therequirements of Clause 10.8.1.3.

10.8.1.2The provisions of Clause 10.8 do not apply to the following situations:(a) corrosive conditions; and(b) the use of galvanized truss plates in lumber that has been treated with a fire retardant and that isused in wet service conditions or in locations prone to condensation.

10.8.1.3Truss plates shall be manufactured from galvanized sheet steel conforming to Grades SQ230, SQ255,SQ275, HSLA I340, HSLA I410, HSLA II340, or HSLA II410 of ASTM Standard A 653/A 653M having theminimum properties given in Table 10.8.1.3.

Table 10.8.1.3Minimum Properties of Steels Used for Truss Plates

Grade SQ230 SQ255 SQ275HSLA I340 orHSLA II340

HSLA I410 orHSLA II410

Ultimate tensile strength, MPa 310 360 380 410 480

Minimum yield, MPa 230 255 275 340 410

Elongation in 50 mm length at failure, % 20 18 16 20 16

Note: Galvanizing may be carried out before manufacture and should be G90 coating class.


August 2001 143

10.8.1.4Joint design shall be based on tight-fitted joints with truss plates placed on opposing faces in such a waythat, at each joint, the plates on opposing faces are identical and are placed directly opposite each other.

10.8.1.5In cases where nail-on plates are used, the word “nail” should be read in place of "tooth".

10.8.1.6Design criteria for truss plates are based on the following conditions:(a) the plate is prevented from deforming during installation;(b) the teeth are normal to the surface of the lumber;(c) tooth penetration in joints is not less than that used in the tests referred to in Clause 10.8.1.9; and(d) the lumber beneath the plate does not contain wane, loose knots, or knot holes.

10.8.1.7Thickness of members used in joints shall be not less than twice the tooth penetration.

10.8.1.8The primary axis of a truss plate, in the case of slotted truss plate tooth configurations, is parallel to thedirection of slots in the plate. For rosette-style configurations, the primary axis is that axis of symmetry inwhich the tensile strength of the truss plate is the greatest.

10.8.1.9Design requirements in Clause 10.8 are for truss plates that have been tested in accordance with CSAStandard S347 for the species group in which the plates are to be used.Note: Test results for such plates are listed in the Registry of Product Evaluations, published by the CanadianConstruction Materials Centre, Institute for Research in Construction, Ottawa, Ontario.

10.8.2 Design

10.8.2.1Truss plate joints shall be designed such that(a) for the strength limit state, the effect of factored loads is less than or equal to

(i) the factored ultimate lateral resistance of the teeth;(ii) the factored tensile resistance of the plates; and(iii) the factored shear resistance of the plates; and

(b) for the serviceability limit state, the effect of specified loads is less than or equal to the lateral slipresistance of the teeth.

10.8.2.2Truss plates shall not be considered to be effective in transferring compression loads at a joint.

10.8.2.3Design of truss plate joints shall take into consideration (a) species of lumber;(b) orientation of plates relative to the applied load (Figure 10.8.2.3, angle D);(c) direction of the applied load relative to the grain (Figure 10.8.2.3, angle 2); and(d) orientation of plates relative to the applied shear force.

10.8.2.4The factored ultimate lateral resistance and the lateral slip resistance of the teeth shall be expressed interms of the surface area of the plates.


144 August 2001

Primary axisof the plate

Direction of theapplied load

θ

ρ

Legend:θ = angle between load direction and grain directionρ = angle between load direction and the primary axis of the plate

10.8.2.5Surface area shall be based on the net area method using the test values, or on the gross area methodusing 80% of the test values, where(a) the gross area is defined as the total area of a member covered by a truss plate; and(b) the net area is defined as the total area of a member covered by a truss plate less the area within agiven distance from the edge or end of the member, as shown in Figure 10.8.2.5. For net areacalculation, the minimum end distance, “a”, measured parallel to grain, shall be the greater of 12 mm or1/2 the length of the tooth; the minimum edge distance, “e”, measured perpendicular to grain, shall bethe greater of 6 mm or 1/4 the length of the tooth.

10.8.2.6The factored tensile resistance of the plates shall be expressed in terms of the dimension of the platemeasured perpendicular to the line of action of the applied forces. The factored shear resistance shall beexpressed in terms of the dimension of the plate measured along the line of action of the shearing forces.

Figure 10.8.2.3Truss Plate, Load, and Grain Orientation


August 2001 145

a

a

e

ea

a

e

ee

e

aa

a

a

Legend:a = end distancee = edge distance

Figure 10.8.2.5End and Edge Distances for Truss Plates

10.8.3 Factored Resistance of Truss Plates

10.8.3.1For the strength limit state, the factored resistances of truss plates shall be determined as follows:(a) For factored ultimate lateral resistance of the teeth

Nr = NNuJH


146 August 2001

nu

puqu

pusin2θ q

ucos2θ

N = 0.9Nu = nu(KDKSFKT)nu = ultimate lateral resistance of the teeth (Clause 10.8.3.2.2)JH = moment factor for heel connection (Table 10.8.3.1)

(b) For factored tensile resistance of the plate

Tr = Ntp

whereN = 0.6tp = tensile resistance of the plate (Clause 10.8.3.2.3)

(c) For factored shear resistance of the plate

Vr = Nvp

whereN = 0.6vp = shear resistance of the plate (Clause 10.8.3.2.4)

Table 10.8.3.1Moment Factors for Heel Joints

of Pitched Trusses, JH

Slope of top chord JH

<1/4 0.85

>1/4 to 1/3 0.8

>1/3 to 1/2.4 0.75

>1/2.4 to 1/2.2 0.7

>1/2.2 0.65

10.8.3.2 Strength Resistance of Truss Plates

10.8.3.2.1 Resistance Values for Plates and TeethResistance values for plates and teeth shall be obtained from tests carried out in accordance with CSAStandard S347, where the resistance values are (a) the average, divided by 1.6, of the three lowest of ten ultimate test values for lateral resistance of theteeth;(b) the average of the two lowest of three corrected test values for tensile strength of the plate; and(c) the average of the two lowest of three corrected test values for shear strength of the plate.

10.8.3.2.2 Ultimate Lateral Resistance of the TeethThe ultimate lateral resistance of the teeth shall be calculated as follows:

(a) For loads parallel to the primary axis of the plate


u

puqu

pusin2θ q

ucos2θ

Ns

psqs

pssin2θ q

scos2θ

where pu, qu, pNu, qNu = ultimate lateral resistances determined in accordance with Clause 10.8.3.2.1(a), used

with the following values of 2 and D:

pu : 2 = 0º, D = 0ºqu : 2 = 90º, D = 0ºpNu : 2 = 0º, D = 90ºqNu : 2 = 90º , D = 90º

where 2 and D are as shown in Figure 10.8.2.3.

When the primary axis of the plate is oriented at an angle other than parallel or perpendicular to thedirection of the load, the resistance value shall be determined by linear interpolation between the valuesnu and nNu.

10.8.3.2.3 Tensile ResistanceTensile resistance of the plate, tp, is determined both parallel and perpendicular to the direction of theapplied load in accordance with Clause 10.8.3.2.1(b).

10.8.3.2.4 Shear ResistanceShear resistance of the plate, vp, is determined for specified angles of plate axis to load direction inaccordance with Clause 10.8.3.2.1(c). For all other angles, shear resistance shall be determined by linearinterpolation. The shear resistance values for tensile mode of failure shall be used where the applied shear forcescreate tension in the plate. Where the applied forces create compression in the plate, the compressiveshear values shall be used. Alternatively, the lower of the two shear resistances for an angle shall beused.

10.8.4 Lateral Slip Resistance

10.8.4.1For the serviceability limit state, the lateral slip resistance of the teeth, Nrs, shall be determined as follows:

Nrs = NsKSF

whereNs = lateral slip resistance of the teeth (Clause 10.8.4.3)

10.8.4.2Resistance values shall be obtained from tests carried out in accordance with CSA Standard S347, wherethe resistance values are the average of 10 test loads at 0.8 mm wood-to-wood slip divided by 1.4.

10.8.4.3The lateral slip resistance of the teeth shall be calculated as follows:

(a) For loads parallel to the primary axis of the plate

August 2001 147

n


148 August 2001

Ns

psqs

pssin2θ q

scos2θ

(b) For loads perpendicular to the primary axis of the plate

where ps, qs, pNs, qNs = lateral slip resistances determined in accordance with Clause 10.8.4.2, used with the

following values of 2 and D:

ps : 2 = 0º, D = 0ºqs : 2 = 90º, D = 0ºpNs : 2 = 0º, D = 90ºqNs : 2 = 90º, D = 90º

where 2 and D are as shown in Figure 10.8.2.3.

When the primary axis of the plate is oriented at an angle other than parallel or perpendicular to thedirection of the load, the resistance value shall be determined by linear interpolation between the valuesNs and NNs.

10.9 Nails and Spikes

10.9.1 GeneralResistance values given in Clauses 10.9.2 to 10.9.5 apply only to common round steel wire nails andspikes and common spiral nails spiralled to head as defined in CSA Standard B111.Note: These provisions are not intended to preclude the use of other types of fastenings and other methods of loadingthe fastenings when appropriate supporting data are available.

10.9.2 Joint Configuration

10.9.2.1For joints nailed at 10% wood moisture content or greater, minimum nail spacings in sawn lumber sideplates and main members shall be as given in Table 10.9.2.1. Additional nails may be staggered on theintersection of diagonal lines drawn between rows of nails (see Figure 10.9.2.1).Note: When the moisture content of the wood is expected to be less than 10% at time of fabrication, minimumspacings and/or end and edge distances should be increased and holes should be predrilled to avoid splitting.


August 2001 149

Table 10.9.2.1Minimum Spacings for Nails and Spikes

Minimum spacing (nail diameters)

Dimension*

Douglas Fir-Larch,Hem-Fir,Western Cedar

Spruce-Pine-Fir,Northern Species

a

b

c

d

Spacing parallel to grain

End distance parallel to grain

Spacing perpendicular to grain

Edge distance perpendicular to grain

20

15

10

5

16

12

8

4

*See Figure 10.9.2.1.


150 August 2001

a

a

Additional nailsstaggered diagonally

between rowsare permitted

d

d

dc

cd

dc

cd

ba

d d

ab bb

d

d

d

d

cc

d

>30º

a

b

d

a

30º <–

Figure 10.9.2.1Nail Spacings for Wood-to-Wood Joints

10.9.2.2Except as given in Clause 10.9.4, the length of penetration shall be at least eight nail diameters in themain member. For spiral nails, the diameter shall be taken as the effective diameter (see Table 10.9.4).

10.9.2.3Side plate thickness shall be at least five diameters of the nail or spike for sawn lumber, or threediameters for plywood and OSB.


August 2001 151

10.9.3 Joint Design

10.9.3.1The factored lateral resistance for nails and spikes driven perpendicular to the grain shall be computedaccording to Clause 10.9.4.

10.9.3.2Where the lateral deformation of nailed or spiked wood-to-wood joints, including structural panel-to-lumber joints, is required for design, joint deformation may be estimated in accordance withClause A10.9.3.2.

10.9.3.3The factored withdrawal resistance per millimetre of nail penetration when driven perpendicular to thegrain shall be computed according to Clause 10.9.5.

10.9.3.4Nails driven into end grain shall not be considered to carry load in withdrawal.

10.9.3.5For a nailed joint having two different species, the factored resistance determined by either Clause 10.9.4or 10.9.5 shall be based on the weaker species.

10.9.4 Lateral ResistanceThe factored lateral strength resistance of the nail or spike connection, Nr, shall be greater than or equalto the effect of the factored loads:

Nr = NNunFJF

whereN = 0.6Nu = nu(KDKSFKT)nu = unit lateral strength resistance (Table 10.9.4), NJF = JS JY JE JA JB JDJS = effective shear planes factor in three-member connections, where nails fully penetrate all members

to obtain double shear and where the nails are either clinched on the far side or driven alternatelyfrom both sides

= 2.00 where the centre member is at least 11 nail diameters in thickness, or= 1.80 where the centre member is at least 8 nail diameters in thickness; interpolate linearly for

thicknesses between 8 and 11 nail diameters = 1.00 in two-member connections

JY = side plate factor= 1.25 for steel side plates= 1.00 for wood side plates

JE = end grain factor= 0.67 for nailing into end grain, and= 1.0 in all other cases

JA = toe-nailing factor= 0.83 for toe-nailing, where toe-nails are started at approximately 1/3 the nail length from the end

of the piece and driven at an angle of 30E to the grain of the member= 1.00 for cases other than toe-nailing

JB = nail clinching factor= 1.6 for nail clinching on the far side in a two-member connection= 1.0 if not clinched, or in three- or more member connections


152 August 2001

JD = factor for diaphragm construction= 1.3 for nails and spikes used in diaphragm construction, or= 1.0 in all other cases

Table 10.9.4Values for nu, Unit Lateral Resistances for

Round Wire Nails, Spikes, and Spiral Nails*, N

Nail characteristics Species groups

TypeLength,inches

Gauge,No.

Diameter,*mm

DouglasFir-Larch Hem-Fir

Spruce-Pine-Fir,NorthernSpecies

Commonwirenails

1 1-1/8 1-1/4 1-1/2 1-3/4 2 2-1/4 2-1/2 2-3/4 3 3-1/4 3-1/2 4 4-1/2 5 5-1/2 6

151514131211-3/4111010 9 9 8 6 5 4 3 2

1.831.832.032.342.642.842.953.253.253.663.664.064.885.385.896.407.01

300 300 380 510 650 780 8701100110014001400170024002900360042005000

260 260 320 420 540 650 730 920 92012001200150020002400290035004100

220 220 260 350 450 530 600 770 77010001000120017002000240028003300

Commonspikes

4 6 7 8 91012

3 1 1 0 0 0 0

6.407.627.628.238.238.848.84

4200550055006600660080008000

3500450045005400540065006500

2800370037004500450057005700

Commonspiralnails

2-1/2 3 3-1/4 3-1/2 4 5

10-1/2 9-3/4 9-3/4 8 7 5

2.773.103.103.864.334.88

720 920 920160020002400

600 790 790130016002000

510 690 690110014001700

*In this table, “diameter” for spiral nails is the effective diameter based on the projected lateral width.

10.9.5 Withdrawal Resistance

10.9.5.1The use of nails and spikes loaded in withdrawal shall be permitted only for wind or earthquake loading.


August 2001 153

10.9.5.2The factored withdrawal resistance of the nail or spike connection, Prw, shall be greater than or equal tothe effect of the factored loads:

Prw = NYwLpnFJAJB

whereN = 0.6Yw = yw(KSFKT)yw = withdrawal resistance per millimetre of penetration (for sawn lumber; see Table 10.9.5.2), N/mm

= (16.4)(d)0.82(G)2.2

whered = nail diameter, mmG = mean relative density based on oven-dry weight and volume (Table A10.1)

Lp = length of penetration into main member, mmJA = toe-nailing factor

= 0.67; or= 1.00 for cases other than toe-nailing

JB = nail clinching factor= 1.6 for nail-clinching on the far side of a two-member connection= 1.0 if not clinched, or in three or more member connections

Table 10.9.5.2Unit Withdrawal Resistance, yw (N/mm), for Round Wire Nails,

Spikes, and Spiral Nails in Sawn Lumber

Nail or spikediameter, mm

DouglasFir-Larch Hem-Fir Spruce-Pine-Fir Northern Species

1.832.032.342.642.842.953.253.664.064.885.385.896.407.017.628.238.84

5.6 6.1 6.9 7.6 8.0 8.3 9.0 9.910.812.513.614.615.616.918.119.220.4

4.9 5.3 6.0 6.6 7.0 7.2 7.8 8.6 9.410.911.812.713.614.715.716.717.7

4.0 4.3 4.9 5.4 5.7 5.9 6.4 7.0 7.7 8.9 9.710.411.112.012.913.714.5

2.72.93.33.63.84.04.34.75.16.06.57.07.58.08.69.29.7

Notes:(1) Tabulated values will be conservative for spiral nails.(2) For length of common wire nails or spikes, see Table 10.9.4.


154 August 2001

10.10 Joist Hangers

10.10.1 General

10.10.1.1Design requirements in Clause 10.10 for joist hangers are for proprietary mass-produced metal devices,usually cold-formed from light-gauge steel or welded from steel plate, that are used to transfer loadsfrom a joist to a header or beam. The joist and header or beam may be sawn lumber, wood trusses,glued-laminated timber, prefabricated wood I-joists, or structural composite lumber.

10.10.1.2The provisions of Clause 10.10 do not apply under the following conditions:(a) corrosive conditions;(b) the use of galvanized joist hangers in lumber that has been treated with a fire retardant and that isused in wet service conditions or in conditions prone to condensation;(c) joist hangers connected to headers or beams of other than wood-based materials; and(d) special hangers having a skew in the horizontal or vertical plane, except skewedhangers with level bearing seats.

10.10.1.3The steel shall have a specified minimum ultimate and yield strength and have specified dimensionalcharacteristics. Sheet steel shall be hot-dip galvanized.Note: Galvanizing may be carried out before manufacturing and should be minimum G90 galvanizing class.

10.10.1.4The joist hanger shall be constructed to meet the following requirements:(a) The height of the hanger shall be at least half the depth of the joist and be capable of providinglateral support for the joist unless the joist is prevented from twisting by other means.(b) The hanger shall be fastened to both the joist and the header or beam. Where nails are used, thesize and spacing shall be sufficient to prevent splitting of the wood. Where bolts are used, the spacingshall conform to Clause 10.4.(c) Hangers used to support prefabricated wood I-joists that do not require bearing stiffeners shall behigh enough to provide lateral stability to the top flange of the joist.(d) Where a prefabricated wood I-joist is the header, backer blocks shall be provided between the weband face mount hangers.(e) Where a prefabricated wood I-joist is supporting a top mount hanger, filler blocks shall be usedbetween the top and bottom flange of the I-joist. The blocks shall be tight to the bottom of the topflange.

10.10.1.5Design requirements in Clause 10.10 are for joist hangers tested for vertical load capacity in accordancewith ASTM Standard D 1761. A set of at least three tests (six hangers) shall be conducted for eachpossible variation of the hanger, wood material, and fasteners, including(a) joist species, size, and type;(b) header species, size, and type;(c) joist hanger size and type; and(d) fastener size, type, and spacing. For sawn wood and glued-laminated timber joists and headers, the relative density of the material usedin testing shall be no greater than 2% above the mean values shown in Table A10.1. For manufacturedwood products, the relative density shall be no greater than 2% above the average of the population. The moisture content of sawn wood at the time of testing shall be 11–19%. For wood products that aremanufactured, installed, and maintained at or below 15% moisture content, the tests shall be made at amoisture content of 8–15%. To allow for relaxation effects, a minimum period of 1 week shall elapsebetween assembly and testing of the specimens.


August 2001 155

10.10.2 Design

10.10.2.1Joist hangers shall be designed so that the effect of the factored loads is less than or equal to the factoredresistance of the hanger.

10.10.2.2For joist hangers attached to the face of a header or beam, the shear resistance of the header or beamshall be checked in accordance with Clause 10.2.1.4.

10.10.3 Factored Resistance of Joist Hangers

10.10.3.1 GeneralThe factored resistance of joist hangers shall be as follows:

Nr = N Nu

whereN = 0.6Nu = nu (KDKSFKT)nu = ultimate resistance of the hanger, per Clause 10.10.3.2KD = the value determined in accordance with Clause 4.3.2, except that no increase for short-term

duration shall be permitted where the ultimate resistance is determined by the strength of the steel

10.10.3.2 Ultimate Resistance of Joist HangersThe ultimate resistance of joist hangers shall be obtained from vertical load tests on no less than threepairs of hangers, conducted in accordance with ASTM Standard D 1761. The ultimate resistance shall becalculated as the lesser of the following:(a) except as provided in Item (b), the ultimate resistance shall be the lowest corrected ultimate load perhanger calculated in accordance with Clause 10.10.3.3, multiplied by 0.91;(b) where ten pairs of hangers are tested, the ultimate resistance shall be the lowest corrected ultimateload per hanger calculated in accordance with Clause 10.10.3.3, multiplied by 1.2; or(c) the average load per hanger at which the vertical movement between the joist and the header is3 mm, multiplied by 2.42.Note: Test results for hangers are listed in the Registry of Product Evaluations, published by the CanadianConstruction Materials Centre, Institute for Research in Construction, Ottawa, Ontario.

10.10.3.3 Corrected Ultimate Load of Joist HangersThe corrected ultimate load per hanger obtained from testing shall be calculated as one-half of theultimate load per test assembly multiplied by the correction factor, CF, calculated from

CF = fu min

fu test

1.0

wherefu min = minimum specified ultimate tensile strength of the steelfu test = ultimate tensile strength of the hanger steel measured in accordance with ASTM Standard E 8

11. Timber Piling

11.1 ScopeDesign tables, data, and methods specified in Clause 11 apply only to the engineering design of piling,


156 August 2001

complying with the requirements of CSA Standard CAN3-O56, as structural members; calculation of thebearing (supporting) capacity of the soil or rock is not included.

11.2 Materials

11.2.1 Preservative TreatmentDesign data and methods specified in Clause 11 are based on the use of piling pressure-treated withpreservative in accordance with the requirements of CSA Standard O80 Series, except as provided inClause 11.2.2.Note: All species covered by CSA Standard CAN3-O56 are not necessarily suitable for pressure treatment withpreservatives. Species of piles to be preservative-treated are restricted to those species listed in CSA Standard O80Series.

11.2.2 Untreated PilingDesign data and methods specified herein may also be applied to untreated piling used for temporaryconstruction.

11.3 Specified StrengthsSpecified strengths for round timber piles shall be as in Table 11.3.

11.4 Modification FactorsThe modification factors in Clause 4.3.2.2 for duration of load and Clause 5.4.2 for service condition shallapply to timber piling specified strengths. No other modification factors shall apply.


11.5.1 GeneralTimber piles may act as end-bearing piles or friction piles and shall be designed to transmit all theapplied loads to supporting soil or rock.

11.5.2 Piles as Compression MembersPiles shall be considered to act as compression members. Where necessary, piles shall be designed towithstand factored bending moments and factored tensile forces due to uplift or other causes, inaccordance with the appropriate provisions of Clause 5.

11.5.3 Effective LengthWhen the finished pile projects above ground level and is not secured against buckling by adequatebracing, the effective length shall be governed by the fixity conditions imposed on it by the structure itsupports and by the nature of the ground into which it is driven. In firm soil, the lower point ofcontraflexure may be taken to be at a depth below ground level of about one-tenth of the exposedlength. Where the top stratum is soft clay, or silt, this point may be taken at about one-half the depth ofpenetration into this stratum, but not less than one-tenth of the exposed length of the pile. Where a pileis wholly embedded, its carrying capacity is not limited by its strength as a long column. However,where there is a stratum of very soft soils or peat, piles shall be designed in accordance with Clause11.5.5.

11.5.4 Embedded Portion

11.5.4.1 GeneralThat portion of a pile permanently in contact with soil or rock providing adequate lateral support shall bedesigned in accordance with Clause 5.5.6, using a slenderness factor KC = 1.00.


August 2001 157

11.5.4.2 End-Bearing PilesThe factored compressive resistance, Pr, of end-bearing piles shall be calculated for an area, A, equal tothe minimum cross-sectional area of the pile.

11.5.4.3 Friction PilesThe factored compressive resistance, Pr, of friction piles shall be calculated over an area, A, equal to thecross-sectional area of the pile at a point 1/3 of the length of the embedded portion of the pile from thetip.

11.5.5 Unembedded PortionThe factored compressive resistance, Pr, of that portion of the pile in contact with air, water, or soils thatdo not provide adequate lateral support shall be calculated in accordance with Clause 5.5.6. Theslenderness factor, KC, shall be calculated using a slenderness ratio, CC, determined in accordance withClauses 12.5.2.5 and 12.5.2.6. Piles subject to eccentric or lateral loads shall be designed in accordancewith Clause 5.5.10.

Table 11.3Specified Strengths and Modulus of Elasticity

for Round Timber Piles (MPa)

Species


Longitudinalshear,fv

Compressionparallelto grain,fc

Compressionperpendicularto grain,fcp

Tensionparallelto grain,ft


E E05

Douglas Fir,Western Larch 20.1 1.4 18.7 7.7 13.6 11 000 7000

Jack Pine 18.1 1.5 15.6 5.2 11.6 7000 5000

Lodgepole andPonderosa Pine 14.2 1.0 13.2 5.2 9.7 7000 5000

Red Pine 13.6 1.2 11.7 5.2 9.0 7000 5000

Notes:(1) Tabulated values are listed for dry service condition and standard-term duration of load.(2) Timber piles using Southern Yellow Pine may be assigned the same resistances as the Douglas Fir-Larch speciesgroup.

12. Pole-Type Construction

12.1 Scope

12.1.1 Round PolesDesign data and methods specified in Clause 12 apply only to the engineering design of round polescomplying with the physical requirements, other than strength properties, of CSA Standard CAN/CSA-O15 as structural members in pole type structures; calculation of the bearing (supporting) capacity of thesoil is not included.

12.1.2 Sawn TimbersSawn timbers used as poles shall comply with the requirements of Clause 5.


158 August 2001

12.2 Materials

12.2.1 Preservative TreatmentDesign data and methods specified in Clause 12 for poles and other wood components that are exposedto soil, moisture, inadequate ventilation, contact with masonry or concrete, or other conditionsfavourable to decay are predicated on the assumption that the poles, etc, are pressure-treated withpreservatives in accordance with the requirements of CSA Standard O80 Series.Note: All species covered by CSA Standard CAN/CSA-O15 are not necessarily suitable for pressure treatment withpreservatives. Species of poles to be preservative-treated are restricted to those species listed in the CSA Standard O80Series.

12.2.2 Short PolesWhen round pole lengths are shorter than specified in CSA Standard CAN/CSA-O15 but meet all otherrequirements of that Standard, the same taper and the same minimum circumference at the top shall beused in calculations.

12.3 Specified StrengthsSpecified strengths for round poles, except Eastern White Cedar, shall be 80% of the specified strengthsfor select structural grade beams and stringers of the appropriate species combination listed inTable 5.3.1C. Specified strengths for round Eastern White Cedar poles shall be 50% of the specifiedstrengths for Select Structural grade beams and stringers of the species combination Northern Species.

12.4 Modification FactorsThe specified strengths for round poles shall be modified by the same modification factors as for beamsand stringers in Clause 5.


12.5.1 General Poles shall be designed to transmit all applied factored loads to the soil and shall be suitable for the soilconditions at the site.

12.5.2 Poles as Compression Members

12.5.2.1 GeneralWhere necessary, poles shall be designed to withstand factored bending moments and factored tensileforces due to uplift or other causes, in accordance with the appropriate provisions of Clause 5.

12.5.2.2 Effective LengthEffective length shall be established in accordance with Clause 11.5.3.

12.5.2.3 Embedded PortionThat portion of a pole permanently in contact with soil or rock providing adequate lateral support shallbe designed in accordance with Clause 5.5.6, using the slenderness factor KC = 1.00.

12.5.2.4 Unembedded PortionThe factored compressive resistance, Pr, of the portion of a pole in contact with air, water, or soil thatdoes not provide adequate lateral support shall be calculated in accordance with Clause 5.5.6. Theslenderness factor, KC, shall be calculated using a slenderness ratio, CC, determined in accordance withClauses 12.5.2.5 and 12.5.2.6. Poles subject to eccentric or lateral loads shall be designed in accordancewith Clause 5.5.10.



12.5.2.5 Constant Nonrectangular Cross-SectionFor nonrectangular compression members of constant section, r shall be substituted for memberwidth or depth in Clause 5.5.6, where r is the applicable radius of gyration of the cross-section of themember.

12.5.2.6 Variable Circular Cross-SectionThe radius of gyration of round tapered compression members shall be calculated for an effectivediameter equal to the minimum diameter plus 0.45 times the difference between the maximum andminimum diameters. The factored compressive resistance determined in this manner shall not exceedthe factored resistance based on the minimum diameter in conjunction with a slenderness factorK = 1.00.C

12.5.3 Poles as Bending MembersThe factored bending moment resistance, M , of round members shall be taken as that of a squarer

member having the same cross-sectional area. A tapered round member shall be considered as anequivalent square member of variable cross-section.

13. Proprietary Structural Wood Products

13.1 ScopeClauses 13.2 to 13.4 provide design methods for proprietary structural wood products that conform tothe applicable referenced standards and the additional requirements contained in Clause 13.Note: Clauses 13.2 to 13.4 are provided as a reference for designers to explain the origin of manufacturers’ proprietarydesign values. In general, proprietary design values are published by the product manufacturer (i.e., proprietary designliterature and/or CCMC Evaluation Reports within the CCMC Registry of Product Evaluations) with appropriate factorsfor specific applications. The designer is not normally expected to calculate the proprietary product properties using theequations provided herein. For applications where adjustments to design values may be warranted, the designer isrecommended to seek guidance from the product manufacturer. For additional information on proprietary structural woodproducts in general, and prefabricated wood I-joists and structural composite lumber products in particular, see theCanadian Wood Council’s Commentary.

13.2 Prefabricated Wood I-Joists

13.2.1 GeneralExcept as specified in Clause 13.2.2.2, all prefabricated wood 3-joists for use under the provisions of thisStandard shall meet the requirements of, and be evaluated for strength and stiffness in accordance with,ASTM Standard D 5055. Determination of characteristic values for design with prefabricated woodI-joists shall be in accordance with Clause 13.2.3.6. All prefabricated wood I-joists for use under the provisions of Clause 13.2 shall bear the mark of acertification organization (C.O.) indicating certification by the C.O. as meeting the applicablerequirements of Clause 13.2.

13.2.2 Materials

13.2.2.1 Flange MaterialsThe provisions of Clause 13.2 apply to flanges as specified in Clause 5 for sawn structurally gradedlumber or Clause 6 for glued-laminated timber. Lumber not conforming to Clause 5 and structuralcomposite lumber products may be used as flange material when such material is qualified by testing asspecified in ASTM Standard D 5055.

13.2.2.2 Structural Panel WebsWebs for prefabricated wood I-joists shall be manufactured from structural panels conforming to



CSA Standard O121, O151, O153 (Exterior Bond), CAN/CSA-O325.0, O437.0, or O452.0. Note: For additional information, see the Canadian Wood Council’s Commentary.

) 13.2.2.3 AdhesivesPrefabricated wood I-joists shall be manufactured using(a) material-specific adhesives conforming to CSA Standard O112.6 or O112.7; or (b) alternative adhesives conforming to the performance-based Standard, CSA O112.9.Note: For additional information on equivalent adhesive systems, see the Canadian Wood Council’s Commentary.

13.2.3 Specified Strengths and Moduli of Elasticity

13.2.3.1 Specified Strength Parallel to Grain, faThe specified strength parallel to grain, f , shall be the lesser of the specified strength in tension parallela

to grain, f , or the specified strength in compression parallel to grain, f , as defined in Clauses 13.2.3.2t c

and 13.2.3.3.

13.2.3.2 Specified Strength in Tension Parallel to Grain, ftThe specified strength in tension parallel to grain, f , shall be determined in one of the following ways:t

(a) where the flange material is sawn lumber conforming to Clause 5.2 or glued-laminated timberconforming to Clause 6.2 of this Standard, the specified strength in tension parallel to grain shall bedetermined from f in Clause 5.3, or f in Clause 6.3, respectively; andt tg

(b) where the flange material is not as described in Item (a), f shall be taken ast

f = t K t r

wheret = the characteristic value for tension parallel to grain as defined in Clause 13.2.3.6, MPaK = reliability normalization factor for bending and tension from Table 13.2.3.2r


August 2001 161

Table 13.2.3.2Reliability Normalization Factors, Kr

(Applicable to Prefabricated Wood I-Joistsand Structural Composite Lumber Products Only)

CVw,*%

Bendingandtension†

Compressionparallel to grain‡

Shear

Prefabricatedwood 3-joists

Structuralcomposite lumber

10 0.88 0.84 0.74 0.59

11 0.88 0.84 0.74 0.59

12 0.88 0.84 0.74 0.59

13 0.88 0.84 0.74 0.59

14 0.88 0.84 0.74 0.59

15 0.88 0.83 0.74 0.59

16 0.87 0.82 0.74 0.58

17 0.86 0.80 0.74 0.57

18 0.84 0.78 0.73 0.56

19 0.82 0.77 0.71 0.55

20 0.80 0.75 0.71 0.54

21 0.79 0.73 0.69 0.52

22 0.77 0.71 0.67 0.51

23 0.75 0.70 0.66 0.50

24 0.73 0.68 0.65 0.49

25 0.72 0.66 0.63 0.48

*CVw shall be determined in accordance with ASTM Standard D 5457.†Applicable to structural composite lumber products in bending and tension. Also applicable to flangesof prefabricated wood I-joist flanges in compression as well as tension.‡Applicable to structural composite lumber products in compression parallel to grain.Note: See also the Canadian Wood Council’s Commentary.

13.2.3.3 Specified Strength in Compression Parallel to Grain, fcThe specified strength in compression parallel to grain shall be determined in one of the following ways:(a) where the flange material is sawn lumber conforming to Clause 5.2 or glued-laminated timberconforming to Clause 6.2 of this Standard, the specified strength in compression parallel to grain shall bedetermined from fc in Clause 5.3, or fc in Clause 6.3, respectively; and(b) where the flange material is not as described in Item (a), fc shall be taken as

fc = c Kr

wherec = the characteristic value for compression parallel to grain as defined in Clause 13.2.3.6, MPaKr = reliability normalization factor for bending and tension from Table 13.2.3.2

13.2.3.4 Specified Shear Capacity, VcThe specified shear capacity, Vc, shall be taken as

Vc = v Kr


162 August 2001

wherev = the characteristic value for shear as defined in Clause 13.2.3.6, NKr = reliability normalization factor for shear for prefabricated wood I-joists from Table 13.2.3.2

13.2.3.5 Modulus of ElasticityThe modulus of elasticity of flange material shall be determined in one of the following ways:(a) where the flange material is sawn lumber conforming to Clause 5.2 or glued-laminated timberconforming to Clause 6.2 of this Standard, the modulus of elasticity shall be determined from Clause 5.3or Clause 6.3, respectively; and(b) where the flange material is not as described in Item (a), the modulus of elasticity shall be the meanvalue of the modulus of elasticity determined from the test results required by ASTM Standard D 5055,Section 6.5.2.1.

13.2.3.6 Characteristic Values(a) The maximum characteristic shear value, v, for prefabricated wood I-joists shall be the shear capacityas defined in ASTM Standard D 5055 and multiplied by 2.37.(b) The maximum characteristic value in tension parallel to grain, t, for flanges of prefabricated woodI-joists shall be taken as

(i) for sawn lumber, the flange tensile capacity as determined in ASTM Standard D 5055 multipliedby 2.1; and

(ii) for structural composite lumber, the characteristic value in tension, tSCL, from Clause 13.4.3.5.(c) The maximum characteristic value in compression parallel to grain, c, for flanges of prefabricatedwood I-joists shall be calculated from one of the following:

(i) for sawn lumber, c shall be calculated from the following:

c = t (fc1/ ft1)

whereft1 = closest assigned specified strength to ft in tension parallel to grain from Clause 5.3 of this

Standard for the species and size tested in accordance with ASTM Standard D 5055fc1 = assigned specified strength in compression parallel to grain from Clause 5.3 of this Standard for

the same grade, species, and size as ft1

(ii) for structural composite lumber, the characteristic value in compression, c, from Clause 13.4.3.4.(d) For prefabricated wood I-joists with either sawn lumber or structural composite lumber flanges,when determined in accordance with the empirical method of Section 6.3.3 of ASTM Standard D 5055,the maximum characteristic value for moment capacity shall be based on the lower 5% tolerance limitwith 75% confidence.

13.2.4 Modification Factors

13.2.4.1 Load Duration Factor, KDThe specified strengths of prefabricated wood I-joists shall be multiplied by a load duration factor, KD, asgiven in Clause 4.3.2.

13.2.4.2 Service Condition Factor, KSThe specified strengths and stiffness of prefabricated wood I-joists described in Clause 13 are applicablefor use in dry service conditions with KS = 1.0.

13.2.4.3 Treatment Factor, KTThe specified strengths and stiffness described in Clause 13 are applicable to untreated prefabricatedwood I-joists with KT = 1.0.



) 13.2.4.4 System Factor, KHThe system factor, K , for prefabricated wood I-joists shall be taken as 1.0.HNote: For additional information, see Appendix X1.4.1 of ASTM Standard D 5055.

13.2.5 Strength and Resistance

) 13.2.5.1 Bending Moment ResistanceThe factored bending moment resistance, M , of prefabricated wood I-joists shall be calculated usingr

either

M = N f K A Y (K K K K K ) Kr a LN net D S H T Zt L

or

M = N M (K K K K ) K Kr cv D S H T r L

whereN = 0.90f = specified strength parallel to grain, per Clause 13.2.3.1, MPaa

K = length adjustment factor, as defined in ASTM Standard D 5055 (see Clause A13.2.5.1)LN

A = net area of one flange, excluding all areas of web material and rout, mmnet2

Y = distance between the flange centroids, with the rout removed, mmK = service condition factor, as per Clause 13.2.4.2S

K = system factor, per Clause 13.2.4.4H

K = the size factor for tension parallel to grain, from Table 5.4.5, applicable only to visually Zt

stress-graded lumber used in accordance with Clause 13.2.3.1K = lateral stability factor, per Clause 13.2.5.2L

M = the characteristic value for moment capacity as defined in Clause 13.2.3.6(d), NCmcv

K = reliability normalization factor for bending and tension, from Table 13.2.3.2r

13.2.5.2 Lateral Stability Factor, KLThe lateral stability factor, K , shall be taken as unity when lateral support is provided at points ofL

bearing, to prevent lateral displacement and rotation, and along all compression edges. Lateral supportrequirements and lateral stability factors for other applications such as continuous spans shall be basedon analytical and engineering principles or documented test data, or both, that demonstrate the safe useof the product in the intended application.Note: For additional information on lateral stability, see the Canadian Wood Council’s Commentary.

13.2.5.3 NotchesNotching or cutting of the flanges of prefabricated wood I-joists shall not be permitted, unless suchdetails have been evaluated and are demonstrated to be acceptable based on documented test data.

13.2.5.4 Shear ResistanceThe factored shear resistance, V , of prefabricated wood I-joists shall be taken asr

V = NV Kr c v

whereN = 0.90V = specified shear capacity for a given brand and depth of prefabricated wood I-joist, in accordancec

with Clause 13.2.3.4, NK = K K Kv D S T

' j



Neglecting loads within a distance from the support equal to the depth of the member shall not bepermitted, and any adjustments to the shear design value near the support shall be substantiated byindependent testing to the shear capacity criteria in ASTM Standard D 5055.

13.2.5.5 Web Openings, Bearing Length, and Web StiffenerRequirementsDesigners shall obtain information regarding web openings, bearing length, and web stiffenerrequirements from specific prefabricated wood I-joist manufacturers. The requirements for permittedweb openings, minimum bearing length, and web stiffener details shall be determined in accordancewith ASTM Standard D 5055.Note: For additional information, see the Canadian Wood Council’s Commentary.

13.2.5.6 Serviceability Limit StatesDesign of prefabricated wood I-joists for serviceability limit states shall be in accordance withClauses 4.1.3 and 4.5. Deflection calculations shall include shear deformation. The flange moduli of elasticity for stiffness calculations shall be taken as

E = E (K K )s SE TE

The effective stiffness, EI , of prefabricated wood I-joist web members employing structural panels inW

Clause 7.3 conforming to CSA Standard O121, O151, CAN/CSA-O325.0, or O452.0 shall be taken as

The shear-through-thickness rigidity, W , of structural panels in Clause 7.3 used as web members ofS

prefabricated wood I-joists and conforming to CSA Standard O121, O151, CAN/CSA-O325.0, or O452.0shall be taken as

W = B K KS v SG TG

whereE = specified modulus of elasticity, per Clause 13.2.3.5K = service condition factor for modulus of elasticitySE

= 1.0 for dry service condition (in accordance with Clause 13.2.4.2)K = treatment factor for modulus of elasticityTE

= 1.0 for untreated prefabricated wood I-joists (see Clause 13.2.4.3)B = axial stiffness (tension or compression) from Table 7.3A, 7.3B, 7.3C, or 7.3D, N/mma

W = overall depth of the structural panel web, mmD

B = shear-through-thickness rigidity from Table 7.3A, 7.3B, 7.3C, or 7.3D, N/mmv

K = service condition factor for shear-through-thickness rigiditySG

= 1.0 for dry service condition (see Clause 13.2.4.2)K = treatment factor for shear-through-thickness rigidityTG

= 1.0 for untreated prefabricated wood I-joists (see Clause 13.2.4.3)Note: Axial web stiffness and web shear-through-thickness rigidity for products not covered by Table 7.3A, 7.3B, 7.3C, or 7.3D must be determined from appropriate standards or documented test data, which can be obtainedfrom the prefabricated wood I-joist manufacturer.

13.2.6 Fastenings

13.2.6.1 NailsNailed connections shall be designed in accordance with Clause 10.9.



13.2.6.2 Joist Hangers and Other Framing ConnectorsThe use of joist hangers and other framing connectors with prefabricated wood I-joists shall be based ondocumented test data.Note: Required details of use and attachment are available from the manufacturers. For additional information, seeClause 10.10 and the Canadian Wood Council’s Commentary.

13.3 Type 3 (Proprietary) Design-Rated OSB Panels

13.3.1 ManufactureType 3 (Proprietary) design-rated OSB structural panels shall be manufactured and their structuralproperties evaluated in accordance with the testing, quality control, and quality assurance andcertification provisions of the CSA Standard O452 Series. Type 3 OSB structural panels may be of anythickness.

13.3.2 Panel Identification and Certificates of ConformanceEach Type 3 (Proprietary) OSB product shall be identified by a distinctive company productdesignation approved by the certification organization. Its compliance with the requirements inCSA Standard O452.0 for Type 3 products shall be verified by the Certificate of Conformance issued bythe certification organization. The Certificate of Conformance shall identify the product designation, thenominal thickness, and the assigned specified capacities (see Clause 13.3.4).

13.3.3 Basic Structural CapacitiesNominal thicknesses and basic structural capacities from which specified design capacities are derivedshall be determined in accordance with the CSA Standard O452 Series.Note: The basic structural capacities are the lower tolerance limits of the mean stiffness and of the lower fifth percentile ofstrength, determined from testing of the mechanical properties, and adjusted to dry service conditions.

13.3.4 Specified Capacities

13.3.4.1 DerivationThe specified capacities for stiffness and strength of Type 3 OSB structural panels shall be derived foreach product from its basic structural capacities in accordance with Clauses 13.3.4.2 and 13.3.4.3.

) 13.3.4.2 Specified Stiffness and RigidityThe specified capacities for stiffness and rigidity for a Type 3 OSB panel shall be its basic structuralcapacities, rounded to two significant figures.

13.3.4.3 Specified StrengthsThe standard term specified strength capacities for a Type 3 OSB panel shall be equal to the basicstrength capacities determined in accordance with the CSA Standard O452 Series multiplied by anadjustment factor of 0.8, and rounded to two significant figures.

13.3.4.4 Application of Specified CapacitiesThe specified capacities determined by Clauses 13.3.4.1 to 13.3.4.3 for a Type 3 OSB structural panelmay be used in design procedures for structural panels specified in this Standard.

13.3.5 Design MethodsDesigns with Type 3 (Proprietary) design-rated OSB shall be in accordance with the modification factorsand design methods for OSB structural panels (see Clauses 7.4 and 7.5).



13.4 Structural Composite Lumber Products

13.4.1 GeneralAll structural composite lumber products for use under the provisions of this Standard shall bemanufactured to, and evaluated for, characteristic values in accordance with the requirements ofASTM Standard D 5456. All structural composite lumber products for use under the provisions of Clause 13.4, includingproducts subjected to secondary processing operations, shall bear the mark of a certificationorganization (C.O.) indicating certification by the C.O. as meeting the applicable requirements ofClauses 13.4.2 to 13.4.6.

) 13.4.2 Adhesives and Binder Systems

13.4.2.1 AdhesivesAdhesives used in the manufacture of structural composite lumber products shall be(a) material-specific adhesives conforming to CSA Standard O112.6 or O112.7; or(b) alternative adhesives conforming to the performance-based Standard, CSA O112.9.

13.4.2.2 Binder SystemsBinder systems shall demonstrate equivalent performance to the adhesives of Clause 13.4.2.1(a).Note: For additional information on equivalent adhesives, see the Canadian Wood Council's Commentary.


13.4.3.1 GeneralSpecified strengths and moduli of elasticity for structural composite lumber products for use with thisStandard shall be established in accordance with Clauses 13.4.3.2 to 13.4.3.7.

13.4.3.2 Specified Bending Strength, fbThe specified bending strength, f , for structural composite lumber products shall be taken asb

f = F Kb B r

whereF = the characteristic value in bending as determined by ASTM Standard D 5456, MPaB

K = reliability normalization factor for bending and tension from Table 13.2.3.2r

13.4.3.3 Specified Shear Strength, fvThe specified shear strength, f , for structural composite lumber products shall be taken asv

f = v Kv SCL r

wherev = the characteristic value in shear as determined by ASTM Standard D 5456, MPaSCL

K = reliability normalization factor for shear for structural composite lumber from Table 13.2.3.2r

13.4.3.4 Specified Compression Strength Parallel to Grain, fcThe specified compression strength parallel to grain, f , for structural composite lumber products shall bec

taken as

f = c Kc r



wherec = the characteristic value in compression parallel to grain as determined by ASTM Standard D 5456,

MPaK = reliability normalization factor for compression parallel to grain from Table 13.2.3.2r

13.4.3.5 Specified Compression Strength, Perpendicular to Grain, fcpThe specified compression strength perpendicular to grain, f (MPa), for structural composite lumbercp

products shall not exceed the characteristic value for compression perpendicular to grain as determinedby ASTM Standard D 5456, multiplied by 1.09.

13.4.3.6 Specified Tension Strength Parallel to Grain, ftThe specified tension strength parallel to grain, f , for structural composite lumber products shall bet

taken as

f = t Kt SCL r

wheret = the characteristic value in tension parallel to grain as determined by ASTM Standard D 5456, MPaSCL

K = reliability normalization factor for bending and tension from Table 13.2.3.2r

13.4.3.7 Specified Modulus of ElasticityThe specified moduli of elasticity, E, for structural composite lumber products shall be the mean modulias determined by ASTM Standard D 5456.


13.4.4.1 Load Duration Factor, KDThe load duration factors, K , as given in Clause 4.3.2 are applicable to the specified strengths ofD

structural composite lumber products, provided that appropriate testing has been conducted thatdemonstrates the validity of those load duration factors for use with the structural composite lumberproduct.Note: See also the Canadian Wood Council’s Commentary.

13.4.4.2 Service Condition Factor, KSThe specified strengths and stiffness of structural composite lumber products described in Clause 13.4.4are applicable for use in dry service conditions with K = 1.0. If structural composite lumber products areS

to be used in other than dry service conditions, the specified strengths and stiffness shall be evaluated,including development of appropriate strength reduction factors, based on documented test results.

13.4.4.3 Treatment Factor, KTThe specified strengths and stiffness described in Clause 13.4.4 are applicable to untreated structuralcomposite lumber products with K = 1.0. Treatment adjustments for specified strengths and stiffnessT

shall be based on the documented results of tests that shall take into account the effects of time,temperature, and moisture content.

13.4.4.4 System Factor, K HThe system factor, K , permitted for structural composite lumber products used in a load-sharing systemH

shall be 1.04. To qualify for the above increase, the structural composite lumber products shall be part of a wood-framing system consisting of at least three parallel members joined by transverse load distributingelements adequate to support the design load and shall not be spaced more than 610 mm on centre.

) 13.4.4.5 Size Factor in Bending, KZbThe size factor in bending, K , for structural composite lumber products shall be taken asZb

' N



K = Zb

whered = specified depth on which the published specified strength in bending, f , is based1 b

d = depth of application membern = parameter defined in Section 7.4.1.3 of ASTM Standard D 5456.

13.4.4.6 Size Factor in Tension, KZtThe size factor in tension, K , for structural composite lumber products shall be taken asZt

K = Zt

whereL = base length between test grips, as tested in Section 5.5.2 of ASTM Standard D 54561

L = end use lengthm = parameter determined in accordance with Annex A1 of ASTM Standard D 5456


13.4.5.1 Bending Moment ResistanceThe factored bending moment resistance, M , of structural composite lumber products shall be taken asr

M = NF SK Kr b Zb L

whereN = 0.90F = f (K K K K )b b D H Sb T

f = specified bending strength, per Clause 13.4.3.2, MPab

K = size factor in bending, per Clause 13.4.4.5Zb

K = lateral stability factor, per Clause 13.4.5.2L

13.4.5.2 Lateral Stability Factor, KLThe lateral stability factor, K , for structural composite lumber products shall be determined inL

accordance with Clause 5.5.4.2.

13.4.5.3 NotchesThe use of structural composite lumber products with notches or cuts shall not be permitted unless suchdetails have been evaluated and are demonstrated to be acceptable based on documented test data.

13.4.5.4 Shear ResistanceThe factored shear resistance, V , of structural composite lumber products shall be taken asr

whereN = 0.90F = f (K K K )v v D Sv T

f = specified shear strength of structural composite lumber products, per Clause 13.4.3.3, MPav

A = cross-sectional area of member, mm2

K = 1.0Zv

Note: For additional information on size factor in shear, K , see the Canadian Wood Council’s Commentary.Zv


August 2001 169

CC


member width

CC


member depth

Kc

1.0FCKZcCC

3

35E05KSEKT

1

13.4.5.5 Compressive Resistance Parallel to Grain

13.4.5.5.1 Effective Length, LeUnless noted otherwise, the effective length, Le = KeL, shall be used in determining the slenderness ratioof structural composite lumber products in compression. Recommended effective length factors, Ke, for structural composite lumber products in compression aregiven in Table A5.5.6.1.

13.4.5.5.2 Slenderness Ratio, CCThe slenderness ratio, CC, of simple compression members of constant rectangular section shall notexceed 50 and shall be taken as the greater of

or

13.4.5.5.3 Factored Compressive Resistance Parallel to GrainThe factored compressive resistance parallel to grain, Pr, of structural composite lumber products shall betaken as

Pr = NFc AKC KZc

whereN = 0.80Fc = fc (KD Ksc KT)fc = specified strength in compression parallel to grain, per Clause 13.4.3.4, MPaA = cross-sectional area of member, mm2

KC = slenderness factor, per Clause 13.4.5.6KZc = 1.0Note: For additional information on size factor in compression parallel to grain, KZc, see the Canadian Wood Council’sCommentary.

13.4.5.6 Slenderness Factor, KCThe slenderness factor, KC, shall be determined as follows:

whereE05 = 0.87E

13.4.5.7 Compressive Resistance Perpendicular to Grain (Bearing)

13.4.5.7.1 Maximum LoadsFactored bearing forces shall not exceed the factored compressive resistance perpendicular to grain inaccordance with the provisions of Clauses 13.4.5.7.2 to 13.4.5.7.4.

13.4.5.7.2 Effect of All Applied LoadsThe factored compressive resistance perpendicular to grain under the effect of all applied loads, Qr, shallbe taken as

Qr = NFcp Ab KB KZcp


170 August 2001

Ab

bLb1

Lb2

2, but 1.5b(L

b1)

whereN = 0.80Fcp = fcp (KD KS KT)fcp = specified strength in compression perpendicular to grain, per Clause 13.4.3.5, MPaAb = bearing area, mm2

KB = length of bearing factor (Clause 5.5.7.6)KZcp = size factor for bearing (Clause 5.5.7.5)

13.4.5.7.3 Effect of Loads Applied near a SupportThe factored compressive resistance perpendicular to grain under the effect of only those loads actingwithin a distance from the centre of the support equal to the depth of the member, QNr, shall be taken as

QNr = (2/3) N FcpANbKBKZcp

whereN = 0.8Fcp = fcp (KDKSKT)fcp = specified strength in compression perpendicular to grain, per Clause 13.4.3.5, MPaANb = average bearing area (see Clause 13.4.5.7.4), mm2

13.4.5.7.4 Average Bearing AreaWhere unequal bearing areas are used on opposite surfaces of a member, the average bearing area shallnot exceed the following:

whereb = average bearing width (perpendicular to grain), mm Lb1 = lesser bearing length, mmLb2 = larger bearing length, mm

13.4.5.8 Compressive Resistance at an Angle to GrainThe factored compressive resistance at an angle to grain shall be calculated in accordance with therequirements of Clause 5.5.8, using the appropriate specified strengths and resistances for theproprietary grade of structural composite lumber products.

13.4.5.9 Tensile Resistance Parallel to GrainThe factored tensile resistance parallel to grain, Tr, of structural composite lumber products shall be takenas

Tr = NFtAnKZt

whereN = 0.90Ft = ft (KD KSt KT)ft = specified strength in tension parallel to grain, per Clause 13.4.3.6, MPaAn = net area, mm2

KZt = size factor in tension, per Clause 13.4.4.6


August 2001 171

Pf

Pr

Mf

Mr

1.0

Tf

Tr

Mf

Mr

1.0

13.4.5.10 Resistance to Combined Bending and Axial LoadMembers subject to combined bending and compressive or tensile axial loads shall be designed to satisfythe appropriate interaction equation:

or

wherePf = factored compressive axial loadPr = factored compressive resistance parallel to grain calculated in accordance with the requirements of

Clause 13.4.5.5.3Mf = factored bending moment, taking into account end moments and amplified moments due to axial


Clause 13.4.5.1Tf = factored tensile axial loadTr = factored tensile resistance parallel to grain calculated in accordance with the requirements of

Clause 13.4.5.9

13.4.5.11 Serviceability Limit StatesDesign of structural composite lumber products for serviceability limit states shall be in accordance withClauses 4.1.3 and 4.5. Deflection calculations shall include shear deformation. The member modulus of elasticity for stiffness calculations shall be taken as

Es = E (KSE KTE)

whereE = specified modulus of elasticity, per Clause 13.4.3.7, MPaKSE = service condition factor for modulus of elasticity

= 1.0 for dry service condition, per Clause 13.4.4.2KTE = treatment factor for modulus of elasticity

= 1.0 for untreated structural composite lumber products, per Clause 13.4.4.3

The shear modulus or shear rigidity, GS, for stiffness calculations shall be taken as

GS = G (KSG KTG)

whereG = specified shear modulus or shear rigidity established by test or as published in a recognized

reference for the structural composite lumber product wood species, MPaKSG = service condition factor for shear modulus

= 1.0 for dry service condition, per Clause 13.4.4.2KTG = treatment factor shear modulus

= 1.0 for untreated structural composite lumber products, per Clause 13.4.4.3

13.4.6 Fastenings

13.4.6.1 Joist HangersThe use of joist hangers with a specific proprietary structural composite lumber product shall conform tothe requirements of Clause 10.10.


172 August 2001

13.4.6.2 Other FasteningsThe procedures and specified capacities for nails, bolts, lag screws, timber rivets, shear plates, trussplates, and split rings in Clause 10 may be used for the design of fastenings for a proprietary structuralcomposite lumber product when testing has demonstrated the validity of those procedures and specifiedcapacities for use with that product.Notes:(1) Design information for some fasteners, primarily nails and joist hangers, applicable for use with specific proprietarystructural composite lumber products are listed in the Registry of Product Evaluations, published by the CanadianConstruction Materials Centre, Institute for Research in Construction, Ottawa, Ontario. Additional design informationfor fasteners for use with specific proprietary structural composite lumber products, including specified capacities, will bedeveloped as test data becomes available. It is recommended that manufacturers list such additional design informationfor their products with the Registry of Product Evaluations.(2) In the absence of design information for specific fasteners in specific proprietary structural composite lumberproducts as set out above, connections for structural composite lumber products should be limited to bearing-typearrangements.


August 2001 173

Appendix AAdditional Information and AlternativeProceduresNotes:(1) This Appendix is not a mandatory part of this Standard. Some clauses have been written in mandatory language tofacilitate their adoption by anyone wishing to do so.(2) Clause numbering within this Appendix corresponds to the clause numbering in the main body of the Standard.

A4.3.5 System Modification Factor, KHIt is well known that the behaviour of a single member does not represent that of a system such as afloor or a flat roof with a number of joists or rafters. System behaviour can be accounted for in singlemember design by implementing system modification factors: KH for strength and K) for serviceability. In this edition of the Standard, only KH has been quantified. The system modification factor, KH, is a function of the parameters that define the mechanical state andphysical layout of the system. These parameters are the mean live load and its coefficient of variation,the mean modulus of rupture and its coefficient of variation, the mean modulus of elasticity and itscoefficient of variation, the MOE-MOR correlation, the sheathing thickness, and the fastening stiffness. The Canadian Wood Council’s Commentary contains further information on this method.

A4.5.2 Elastic Deflection of Wood Light-Frame Systems under StaticLoads

A4.5.2.1 Wood Frame Deflection CalculationsWood frame systems connected with sheathing or cladding on one or both sides deflect less than thejoists, rafters, or studs carrying the same loads independently. Traditionally, however, deflectioncalculations have ignored this interaction and assumed that each framing member in these systems isloaded individually on its tributary area. The deflection criteria that evolved from this approach haveprovided satisfactory system performance based on calculated single member deflections. It is possible to estimate system performance by calculating system factors greater than 1.0 as a ratio ofsystem deflection to single member deflection. Caution should be used when implementing systemfactors in traditional design procedures. Where design procedures incorporate a system factor fordeflection, there is a need to consider whether the system effects add to enhancements that are alreadypresent in traditional wood frame performance, before adjusting design procedure criteria.

A4.5.2.2 Elastic Deflection of Stud Wall Systems under Wind LoadTypical wood stud wall systems sheathed with wood panel products and designed for a single memberdeflection of 1/360 of the span may satisfy the intent of masonry design specifications intended to limitthe deflection of steel studs in high-rise buildings to 1/720 of the span. For example, the actual deflection would be approximately half of the deflection calculated on a singlemember basis under the following conditions:(a) lumber modulus of elasticity (see Table 5.3.1A) derived from visually graded lumber data;(b) lumber used in a stud wall system (i.e., 38 × 89 mm or 38 × 140 mm) meeting minimumrequirements for Case 2 system factor (see Clause 5.4.4.2);(c) gypsum wallboard or structural sheathing attached to the inside face of the studs in accordancewith minimum building code requirements; and(d) cladding and secondary member wind loading based on the tributary area of a stud in a low-risebuilding.

A4.5.5 Floor VibrationServiceability design of wood-framed floor systems, like other floor systems, has traditionally been


174 August 2001

addressed by limiting the computed joist deflection under a uniform load. For some floor systems andend uses, traditional criteria have provided satisfactory performance. However, these criteria do notalways restrict floor vibration to the satisfaction of occupants. Vibration design of wood-framed floorsystems has evolved from a single limitation on maximum uniform load deflection (e.g., 1/360 or 1/480of span) to a dual check that adds a limitation on point load deflection (see, for example, NationalBuilding Code of Canada, Part 9). While the point load deflection check has proven to be adequate for traditional sawn lumber joist floors,it does not adequately address the broad range of application variables that occur in engineered woodproduct floor systems. The span capabilities and optimization of engineered wood floor systems maymerit a more refined analysis procedure. This may take the form of recommended maximum spans orcalculation procedures. Users are advised to exercise judgment in applying simplified criteria when attempting to limitobjectionable floor vibrations in these systems. Particular emphasis should be placed on naturalfrequency (related to mass and stiffness), relative along-joist and across-joist system stiffnesses, and theeffectiveness of between-joist bridging/blocking systems. In addition to the guidance provided by the NRC’s Structural Commentaries to Part 4 of the NationalBuilding Code of Canada, users are directed to the Canadian Wood Council’s Commentary, to assist intheir assessment of floor vibration issues for their specific applications.

Table A5.5.2Minimum Dressed Sizes of Dimension Lumber and Timbers*

Item

Smaller dimension, mm Larger dimension, mm

Dry Green Dry Green

Dimensionlumber

38 51 64 76 89102

40 53 66 78 91104

38 64 89114140184235286337387

40 66 91117143190241292343393

Timbers 114140165191216241292343394

114140165191216241292343394

*Sizes are rounded to the nearest whole millimetre and are based on CSA Standard CAN/CSA-O141.Notes:(1) Dry lumber is defined as lumber that has been seasoned or dried to a moisture content of 19%or less.(2) Green lumber is defined as lumber having a moisture content in excess of 19%.


August 2001 175

Effectively held in position and restrained againstrotation at one end but not held in position norrestrained against rotation at the other end

Note: Effective length Le =KeL, where L is the distance between centres of lateral supports of the compressionmember in the plane in which buckling is being considered. At a base or cap detail, the distance shall be measuredfrom the outer surface of the base or cap plate. The effective length factor, Ke, shall be not less than what would be indicated by rational analysis. Where conditions of end restraint cannot be evaluated closely, a conservative value forKe shall be used.

Effectively held in position and restrained againstrotation at both ends

Effectively held in position at one end but notrestrained against rotation, and at the other endrestrained against rotation but not held in position

Effectively held in position and restrained againstrotation at one end, and at the other partiallyrestrained against rotation but not held in position

Effectively held in position and restrained againstrotation at one end, and at the other restrainedagainst rotation but not held in position

Effectively held in position at both ends, but notrestrained against rotation

Effectively held in position at both ends, restrainedagainst rotation at one end

Degree of end restraint ofcompression member

Effective lengthfactor, Ke

Table A5.5.6.1Minimum Design Values of Effective

Length Factor, Ke, for Compression Members

Symbol

2.00

2.00

1.50

1.20

1.00

0.80

0.65

A5.5.6.1 Effective Length Factor, Ke

A5.5.6.3 Spaced Compression Members

A5.5.6.3.1 GeneralSpaced compression members shall consist of two or more individual members joined with timberconnectors and having spacer and end blocks as specified in Clauses A5.5.6.3.2, A5.5.6.3.3, andA5.5.6.3.4.

A5.5.6.3.2 Spacer and End BlocksRequirements for spacer and end blocks are as follows:(a) End blocks shall be so placed that end and edge distances and spacing, as required in Clause 10 forthe size and number of connectors, are maintained in end blocks and in individual members. Connectorsshall be placed so that the limits according to Clause A5.5.6.3.3, depending on the fixity factor assumed,


176 August 2001

CC

actual length between points of lateral support

least dimension of an individual member

are met. In compression members of trusses, a panel point that is stayed laterally may be considered asthe end of the spaced member.(b) A single spacer block shall be located within the middle 10% of the length of the compressionmembers; when so located, connectors are not necessary for this block. When more than one spacerblock is used, the distance between any two blocks shall not exceed one-half the distance betweencentres of connectors in the end blocks. The requirements for connectors shall be the same as for endblocks, when two or more spacer blocks are used.(c) The thickness of spacer and end blocks shall be not less than that of the individual members of thespaced compression member, except that spacer and end blocks of a thickness between that of theindividual members and one-half that thickness may be used, provided that the length of the blocks ismade inversely proportional to the thickness in relation to the required length of full-thickness block. Spacer and end block sizes shall be adequate to develop the strength required by Clause 10.

A5.5.6.3.3 Fixity ClassesSpaced compression members shall be classified as to end fixity either as condition “a” or condition “b”,as follows (see Figure A5.5.6.3):(a) for condition “a”, the centroid of connectors or of the connector group in the end block shall bewithin one-twentieth of the length, L, from the end of the member; and(b) for condition “b”, the centroid of connectors or of the connector group in the end block shall bebetween one-twentieth and one-tenth of the length, L, from the end of the member.

A5.5.6.3.4 Connectors in End BlocksThe connectors in each pair of contacting surfaces of end blocks and individual members at each end ofa spaced compression member shall be at least of a size and number to provide a factored strengthresistance (N) equal to the required cross-sectional area in square millimetres of one of the individualmembers multiplied by the appropriate end block constant listed in Table A5.5.6.3.

A5.5.6.3.5The slenderness ratio, CC, of spaced compression members of uniform rectangular section shall notexceed 80 and shall be taken as

A5.5.6.3.6 Factored Compressive Resistance Parallel to GrainThe factored compressive load resistance, Pr, parallel to grain shall be taken as

Pr = NFcAKCKZc

whereN = resistance factor (Clause A5.5.6.3.7)Fc = fc (KDKSCKT)fc = specified strength in compression parallel to grain (Tables 5.3.1A and 5.3.3 for sawn lumber and

Table 6.3 for glulam), MPaA = total cross-sectional area, mm2

KC = slenderness factor (Clause A5.5.6.3.7)KZc = size factor

= 6.3(dL)-0.13 < 1.3 for sawn lumber= 1.0 for glued-laminated timber

d = member dimension in direction of buckling (depth or width), mmL = column length associated with member dimension, mm


August 2001 177

Kc

11

3

CC

CK

4

CK

0.76E05KSEKEKT

Fc

Kc

E05KSEKEKT

kC2

CFc

CC

actual length between points of lateral support

larger dimension of an individual member

A5.5.6.3.7 Resistance Factor, N, and Slenderness Factor, KCThe resistance factor, N, and the slenderness factor, KC, shall be determined as follows:

N = 0.80 for sawn lumber= 0.90 for glued-laminated timber

(a) when CC does not exceed 10

KC = 1.00

(b) when CC is greater than 10 but does not exceed CK

whereE05 = the applicable value from Tables 5.3.1A to 5.3.1D for visually graded sawn lumber

= 0.82E for MSR lumber= 0.87E for glued-laminated timber

KE = end fixity factor (see Clause A5.5.6.3.3)= 2.50 for condition a= 3.00 for condition b

(c) where CC is greater than CK but does not exceed 80

wherek = 1.8 for sawn lumber

= 2.0 for glued-laminated timber

A5.5.6.3.8 Design Check of Spaced Compression MembersThe factored resistance determined by spaced compression member design shall be checked against thesum of factored resistances of individual members taken as simple compression members. In this check

The factored compressive resistance, Pr, shall be the smaller value obtained by the two methods ofevaluation.

A5.5.6.3.9 Combined StressesWhen axial compression in spaced compression members is combined with bending stresses, theprovisions of Clause 5.5.10 shall be used only if the bending is in a direction parallel to the largerdimension of the individual member.


178 August 2001

L = distance between points of lateral support of continuous or simple spaced compression members (mm)

Condition “a” with the connectors within L / 20 from end of member

Condition “b” with the connectors placed from L / 20 to L / 10 from end of member

Smallerdimension

Largerdimension

End block

Spacer block

End block

Table A5.5.6.3End Block Constants for Spaced Compression Members, MPa

CC* D Fir-L Hem-Fir S-P-F Northern

0–1015202530354045505560–80

0.000.380.791.21.51.92.22.63.03.43.8

0.000.300.620.921.31.51.92.22.52.83.0

0.000.260.550.811.11.41.61.92.22.52.6

0.000.230.470.720.961.21.51.61.92.22.3

*Constants for intermediate values of CC may be obtained by straight-line interpolation.

Figure A5.5.6.3Spaced Compression Member (Connector Joined)



) A5.5.7 Compression Perpendicular to GrainA relationship between mean compression perpendicular to grain strength and mean oven-dry wooddensity was introduced to establish a consistent basis for bearing strengths for various products in the1994 edition of this Standard. It is as follows:

f = 0.9 L (2243.8 D – 473.8) / Mcp

where f = specified compression perpendicular to grain strength, MPacp

0.9 = factor applied to obtain a lower tolerance limitL = conversion factor to limit states design (LSD) and standard-term load duration

= 1.8125D = mean oven-dry density (g/cm )3

M = conversion factor for metric units = 145.038

Tables 5.3.2 and 5.3.3 assign increased compression perpendicular to grain design values to specificgrades of S-P-F or Hem-Fir machine-graded lumber, which have higher mean density than visuallygraded lumber of the same species (see Table A10.1). The NLGA grading rules also include provisions for mills producing any grade of machine-gradedlumber to qualify for other density values based on tests, daily quality control, and marking the qualifieddensity value on the lumber. In these cases the NLGA rules provide for compression perpendicular valuesto be based on the marked density value and the formula shown above, without the 0.9 tolerance limit.

A5.5.12 Preserved Wood Foundations

A5.5.12.1Studs for preserved wood foundations may be designed in accordance with recognized engineeringmethods. When assumed to be laterally supported, and when no surcharge exists, the formulaepresented in Clauses A5.5.12.6 to A5.5.12.12 give conservative approximations of sufficient accuracy forpractical construction. Dimensions used in the formulae are identified in Figure A5.5.12.1.

A5.5.12.2Studs for exterior foundation walls may be designed as members subjected to combined bending andaxial compressive loading. Deflection due to lateral and axial loads should not exceed 1/300 of theunsupported height of the stud.

A5.5.12.3Sheathing for exterior foundation walls may be designed as simple bending members. The calculatedmaximum deflection at a point 300 mm above the bottom of the sheathing should not exceed 1/180 ofthe span of sheathing between studs. The nominal thickness of sheathing should not be less than12.5 mm.

A5.5.12.4Floors and connections between floors and walls shall be designed to withstand loads imposed uponthem by lateral soil pressure as well as floor loads appropriate for the occupancy.

A5.5.12.5Unequal pressure distribution may result from differing backfill heights on opposite sides of a building,openings in foundation walls, openings in floors at the top of foundation walls, or other causes. Framingmembers and sheathing shall be designed to resist loads resulting from unequal pressure distribution, bydiaphragm action, or by other suitable means.

% )%

' &&

&&

' & %

' &

'

' & %% &

&



A5.5.12.6Combined bending and axial load effects may be evaluated using the formula

whereM = maximum factored moment due to lateral load on stud, NCmmf

P = factored axial load on stud, Nf

) = deflection due to lateral load at point where M is calculated, mmf

M = factored bending moment resistance, in accordance with Clause 5.5.4.1, NCmmr

P = factored compressive resistance, in accordance with Clause 5.5.6.2.2, Nr

Notes:(1) A K factor of 0.65 applies to the calculation of M and a K factor of 1.0 applies to the calculation of P .D r D r(2) The value of P ) represents secondary bending, which may be negligible.f

A5.5.12.7The value of M in Clause A5.5.12.6 is the maximum moment due to factored lateral load, and may bef

calculated using the following expression derived from recognized engineering formulae. At any point,x, above the floor the factored bending moment, M (NCmm), isfx

wherew = maximum factored lateral load per stud, N/mmf

= maximum factored lateral soil pressure, N/mm , times stud spacing, mm2

H, L, a, x = variables shown in Figure A5.5.12.1, mm

A5.5.12.8The following formulae may be used to determine the maximum factored moment, M , f

and its location, x:(a) for wood sleeper and slab floors

and

(b) for suspended floors, both the moment between supports and the cantilever moment at the supportshould be checked using

where

'&

' & &&

'&

'

) '&

)


January 2005 180A

and between supports

at the support

Note: Values of K for a range of backfill heights and typical wall dimensions are given in Table A5.5.12.8.m

A5.5.12.9Secondary moment is the term P ) in Clause A5.5.12.6. The value of ) may be calculated at any point,f

x, above the basement floor (see Figure A5.5.12.1), using the formula


August 2001 181

K∆

[10H 2(H 3a)(2L x)x 3(H a)5 K2]

K2

3L

L x(H a x)5 when x H a

Vf

wfH

2

H

3L

H d

H

2

Vf

wfH

2

H 3a

3L

H a c

H

2

Vf

wfH

21

H a c

H

2

RT

wfH 2

6L

where

= 0 when X > H – aE = modulus of elasticity of stud, MPa3 = moment of inertia of stud, mm4

wf = variable shown in Figure A5.5.12.1, N/mmH, L, a = variables shown in Figure A5.5.12.1, mm

Notes:(1) ) is normally calculated at the point where maximum moment occurs. If the maximum moment occurs at thesupport (due to cantilever effect), ) = O.(2) Values of K) for a range of backfill heights and typical wall dimensions are given in Table A5.5.12.8.

A5.5.12.10Maximum deflection may be calculated from Clause A5.5.12.9 with x = 0.45L, and using specified ratherthan factored loads, to give a good approximation of the theoretical maximum deflection.

A5.5.12.11Maximum longitudinal shear may be calculated from the following expressions derived from recognizedengineering formulae, and identified as the greatest value of Vf:(a) for wood sleeper and slab floors at bottom of the foundation wall

(b) for suspended floors

just above the suspended floor, and

just below the suspended floor

whereVf = factored shear force per stud, Nc = depth of stud + 1/2 of the joist depth, mmd = depth of stud, mmwf = variable shown in Figure A5.5.12.1, N/mmH, L, a = variables shown in Figure A5.5.12.1, mm

A5.5.12.12Lateral restraint required at top of the foundation wall may be calculated from the following expressions:(a) for wood sleeper and slab floors


182 August 2001

RT

wfH

2L

H

3a

RB

wfH

2LLH

3

RB

wfH

2LL a

H

3

(b) for suspended floors

Lateral restraint required at the bottom of the foundation wall may be calculated from the followingexpressions:(c) for wood sleeper and slab floors

(d) for suspended floors

whereRT = inward reaction at top of stud, NRB = inward reaction at bottom of stud, Nwf = variable shown in Figure A5.5.12.1, N/mmH, L, a = variables shown in Figure A5.5.12.1, mm

Table A5.5.12.8Moment and Deflection Coefficients, Km and K),

for Typical Values for L and a*

Backfillheight,H, mm

Slab floor Suspended floor

Km†

K) × 1015 K) × 1015

At point ofmaximummoment At x = 0.45L

At point ofmaximummoment At x = 0.45L

400 600 80010001200140016001800200022002400260028003000

0.85 3.8 11 23 43 71110150200260320———

2.5 8.4 20 37 62 94130180230280340———

— 0 0 0 0 0 0 0 0 96150200270330

—–14–20–22–19–10 6.3 31 64110150210260320

—–3800–2300–1600–1100 –840 –660 –530 –430 400 430 450 450 450

*Tabulated coefficients are for the cases where L = 2400 mm, a = 0 mm for a slab floor and L = 2500 mm, a = 500 mm for a suspended floor.†Values for Km (last column) apply only to foundations with suspended floors. Tabulated are the greater of thecalculated values for Km at the support (negative numbers) or between supports (positive numbers). K) at the point ofmaximum moment (fourth column) is zero where moment at the support governs.


August 2001 183

x

RB

RT

Pf

a

wf

L

H

Surfaceof backfill

Suspended floor system

x

RB

RT

Pf

wf

L

H

Surfaceof backfill

Slab floor system

Legend:L = Stud length (mm)x = Location of maximum moment (mm)H = Height of backfill (mm)

Floor system

Figure A5.5.12.1Dimensions and Loading of Foundation Studs without Surcharge

A5.5.13 Sawn Lumber Design for Specific Truss Applications

A5.5.13.1 Scope

Fully triangulated — The modified design procedures of Clause 5.5.13 are based on research reportedby C. Lum, E. Jones, and B. Hintz (Design of Wood Trusses for Small Buildings, Proceedings of theInternational Wood Engineering Conference, New Orleans, LA, Vol. 1, 1996). They apply only to sawnlumber used in trusses where all of the members form a side of a triangle. In such a system, a bendingfailure at a panel point of a compression member would not normally result in collapse of the triangle. An attic truss is not a fully triangulated system. Also, the ends of top chords in top chord bearing trusses,and top chord overhangs (i.e., outward extensions of truss chords beyond the panel points) do not fallwithin the scope of Clause A5.5.13 and therefore are not considered part of the overall truss length.

Clear span limitation — The 12.2 m clear span limitation is consistent with that for snow loading forNational Building Code of Canada (NBCC) Part 9 structures (NBCC, Subsection 9.4.2). When the 12.20 mspan limit is exceeded or when other conditions are in effect, an 80% snow load factor must be used(i.e., the truss is designed as a Part 4 truss). When the 610 mm spacing limit is exceeded, the 80% snowload factor must be used and the KH factor in CSA Standard O86 is reduced from 1.1 to 1.0. Note that


184 August 2001

neither the CSA Standard S307 test nor the testing done in the research program is intended to addresssystem effects.

Truss configuration — Clause A5.5.13 limits the applicability of Clause 5.5.13 to roof trusses withslopes that are similar to those trusses tested. Compared to the standard pitched chord trusses evaluatedin the testing program, very low pitch (less than 2 in 12) roof and flat trusses have a higher axial force tobending moment ratio and are excluded from coverage in this Standard. The overall length is a limit that the truss industry has traditionally used to place additional limits ondesign. The two limits, 12.20 m clear span and the 18.0 m overall length, provide a boundary betweentraditional residential spans and long span roof trusses. Below the 18.0 m overall truss length limit, thetruss may consist of cantilevers and/or multiple clear spans, provided that no single span exceeds12.20 m. Girder, bowstring, semi-circular, attic, flat, and floor trusses continue to be designed to the balance ofthe Standard.

A5.5.13.3 Compressive Resistance Parallel to Grain

Effective length — The Standard recommends effective length factors that it tabulates inTable A5.5.6.1. In addition, TPIC Truss Design Procedures contains specific recommendations for effectivelength of truss compression members. The selection of these factors depends on the load distributionand the type of structure.

Compression chord splices — For purposes of strength and deflection calculations, a compressionchord splice may be considered continuous, provided that it is located at an inflection point for the loadcase being considered. To allow for changes in lumber length, the splice need only be within ±10% ofthe panel length from the inflection point. This allowance also recognizes that the location of theinflection point will depend on the loading condition.

Size effects in compression — In most cases, the member length for computing KZc is the panellength: between panel points, the axial force changes little compared with at the panel points. In caseswhere the axial stresses are high, relative to the bending stresses, resulting in relatively short panellengths, and where the axial forces are relatively constant between adjacent panels, the member lengthfor computing KZc should include several panels. One-half the chord length between pitch breaks hasbeen judged to be sufficient to cover these cases. A pitch break is a point along the chord analogue line where the slope of the chord changes.

A5.5.13.4 Compressive Resistance Perpendicular to Grain

Bearing reinforcement — Bearing reinforcement consists of applying truss plates to both sides of amember that may be subjected to compression perpendicular to grain stresses through the depth of themember. Designs are also required to meet the basic bearing requirements of Clause 5.5.7.1. Testing tosupport this method of improving the bearing resistance is described in F.J. Keenan et al., “Improvingthe Bearing Strength of Supports of Light Wood Trusses”, Can. J. Civil Engineering, 10 (1983),pp. 306–312.

A5.5.13.5 Resistance to Combined Bending and Axial Load

Interaction equation — The modification to the axial ratio term was introduced to recognize theincrease in bending capacity when a brittle material is subjected to axial compression in addition tobending. The KM factor is used to adjust the bending capacity for various moment configurations in thetop chords. These two changes to the design of compression chords help to explain the satisfactorylevels of safety observed in the test trusses. No increase is permitted for combined tension and bending members, as the testing program was notdesigned to evaluate the performance of tension chord members.


August 2001 185

Amplified moments — The proposed design procedures have been written to cover the general casewhere amplified moments are used. Although moment amplification should not be ignored, somestructures may be accurately analyzed without having to use analysis methods that include momentamplification. An analysis of moment amplification in trusses indicated that mid-panel moments were more susceptible to P-delta effects, while panel point moments were less susceptible. Furthermore, theamount of moment amplification computed is sensitive to the type of structure and the analogueassumptions. Results from the testing program suggests that the design procedure currently in use by TPIC results intrusses that exhibit satisfactory levels of performance. The TPIC design approach does not includemoment amplification; however, the procedure does require that the mid-panel deflection be limited. This, in effect, limits the length of truss panels, even though the chord member may possess sufficientstrength. If the deflection limitations in TPIC Truss Design Procedures are not used to limit panel length,the bending capacity modification factors, KM, from Table 5.5.13.5 may not be appropriate.

Bending capacity modification factor, KM — The KM factors calculated from Table 5.5.13.5 arebased on analysis done by the UBC Wood Science Department (W. Lau, J.D. Barrett, F. Lam, ChordMember Design Proposal, University of British Columbia, Vancouver, 1995). In addition to being afunction of the member’s span-to-depth ratio, the KM factor also depends on the shape of the momentdiagram. A KM greater than 1 generally indicates a bending moment distribution with one or more inflectionpoints in the member between panel points, and a panel point moment that is higher than the mid-panel moment. For cases where the mid-panel moment is higher than the panel point moments or where the loadingis such that there are no inflections points in the panel, the KM factor is generally less than 1. For other cases where the structural analysis indicates zero moment at the panel points (i.e., M2 = 0),the bending capacity increase will simply be a function of the span-to-depth ratio. This generally occursat pitch breaks or panel point splices, where, although the bending moments may not be zero, designerstraditionally assume a pin connection. However, a fictitious analogue member, such as that used tomodel a heel joint in a pitched chord truss, is considered to introduce a panel point moment in the heel. Therefore, the top chord of a king post truss can be assumed to be continuous over a panel point at theheel, but not at the peak. The test trusses and trusses analyzed in the impact study, which are considered typical designs, result invalues of KM up to 1.3. The upper limit on KM at 1.3 has been introduced to prevent extrapolation tohigher values.

A6.5.5 Standard Sizes for Glued-Laminated TimberThe standard dimensions for glued-laminated timber are as follows:(a) widths of 80, 130, 175, 215, 265, 315, and 365 mm; and(b) depths, as calculated for

(i) straight or cambered members, in multiples of 38 mm; and(ii) members curved to a radius of curvature less than 10 800 mm, in multiples of the required

lamination thickness (Table A6.5.5).Notes:(1) Actual widths commercially available may vary.(2) For widths greater than 365 mm, designers are advised to check availability before specifying.


186 August 2001

Table A6.5.5Minimum Radius of Curvature

Minimum radius of curvature, mm

Lamination thickness, mm Tangent end* Curved end

38 Standard19 Standard

84002800

10 800 3800

35 Non-standard322925161310 6

7400630056004600230018001200 800

9500 8500 7300 6200 3000 2200 1400 800

*Tangent end requires a straight length of finished lamination beyond thetangent point of not less than 32 times the lamination thickness.

A7.2.2.2 Construction Sheathing OSBAs identified in its preface, CSA Standard CAN/CSA-O325.0 does not contain recommended engineeringdesign values, nor does it suggest methods of calculating such values. Design values contained in Table 7.3D for Construction Sheathing OSB certified to CSA StandardCAN/CSA-O325.0 are consistent with values developed by in-grade testing and supported by variousorganizations. Certification organizations shall ensure that reference values for bending strength and bending stiffnessof Construction Sheathing OSB certified to CSA Standard CAN/CSA-O325.0 are also consistent with thedesign values of this Standard. OSB panels marked to CSA Standard CAN/CSA-O325.0 are technically equivalent to OSB panelsmarked to the U.S. NIST Standard PS2, which uses a different span rating designation.

Table A7.2.2.2A Panel Marks for Construction Sheathing Products (CSA O325)

(a) Panel Marks

End usemarks

Span marks

16 20 24 32 40 48

Recommended framing member spacing, mm

400 500 600 800 1000 1200

1F 1F16 1F20 1F24 1F32 X 1F48

2F 2F16 2F20 2F24 X X X

1R 1R16 1R20 1R24 1R32 1R40 1R48

2R 2R16 2R20 2R24 2R32 2R40 2R48

W W16 W20 W24 X X X

X = Not available.

Notes:(1) Panel marks comprise an end use mark (see (b) below) followed by the appropriate span mark (in inches), e.g.,2F24/W16.(2) Multiple panel marks may be shown on panels qualified for more than one end use, e.g., 1R24/2F16 or2R48/2F24/1F24.


August 2001 187

(3) The span mark relates to the centre-to-centre spacing of supports (test span) used for the qualification testing ofConstruction Sheathing products. These spans are based on assumed end use and framing member spacings normallyfound in light wood-frame construction. The framing member itself shall be designed for the expected loads usingrecognized engineering procedures.

(b) End Use Marks

For panels marked Assumed end use

1F Subflooring

2F Subflooring used with panel-type underlay

1R Roof sheathing used without edge support

2R Roof sheathing used with edge support

W* Wall sheathing

*Panels marked W only are not permitted by this Standard.Note: Panels marked 1 are usually stiffer than panels marked 2.

Table A7.2.2.2BRelationship between Panel Mark and Nominal Thickness

Panel mark

Nominal thickness, mm

7.5 9.5 11 12 12.5 15 15.5 18 18.5 22 25 28.5

2R20 P

2R24 P A A A

1R24/2F16 P A A

2R32/2F16 P A A A

2R40/2F20 P A A A

2R48/2F24 P A A

1F16 P A

1F20 P A

1F24 P A

1F32 P A

1F48 P

Note:P — indicates the predominant nominal thickness for each panel mark.A — indicates alternative nominal thicknesses that may be available for each panel mark. Check with suppliersregarding availability.

A7.3.1 Plywood Specified CapacitiesThe specified capacities for plywood in Tables 7.3A and 7.3B are predicated on the following restrictions:(a) In panels with an even number of plies, only a single pair of plies with grain parallel to each other ispermitted.(b) In panels of nominal thickness greater than 20.5 mm, the maximum outer ply thickness is 3 mm.(c) In panels of nominal thickness greater than 20.5 mm, the maximum inner ply thickness is 4.2 mm.


188 August 2001

Br

NXB

(2hw

ht

hc)(109)

2(sp)2

d1

d2

2

A8.6.3.4 Buckling of Plywood Compression FlangeFor stressed skin panels with a plywood compression flange, the factored buckling resistance, expressedas the maximum factored load applied perpendicular to the compression flange, shall be taken as

whereBr = factored buckling resistance, kN/m2

N = 0.95XB = buckling coefficient (Table A8.6.3.4)s = clear spacing between longitudinals, mmRp = span of stressed skin panel, mm

Note: This clause is not applicable to OSB compression flanges. Buckling coefficients have not been developed for OSB.

Table A8.6.3.4Buckling Coefficient, XB, for the Plywood Compression

Flange of Stressed Skin Panels, kNCm

Unsanded plywoodthickness (mm) Face grain parallel to span Face grain perpendicular to span

7.5 9.512.515.518.520.5

23 59160*350610880

53 110 240 470 7901050

*For 12.5 mm, 3-ply plywood and face grain parallel to span, use XB = 120.

A9.5.1 Alternate Nails in ShearwallsFor shearwalls and diaphragms fabricated using nails having a diameter that deviates from the standardcommon nail diameter, and meeting the following criteria:(a) the non-standard nail diameter is within 80% of that of a standard common nail; and(b) the yield strength of the non-standard nail is at least

(i) 660 MPa for nail diameter 2.34–2.84 mm; (ii) 635 MPa for nail diameter 2.64– 3.25 mm; and (iii) 615 MPa for nail diameter 2.95–3.66 mm.

The design capacities may be estimated by multiplying the capacities presented in Tables 9.5.1A and9.5.2 by the multiplication factor given below:

Multiplication factor =

whered1 = the non-standard nail diameter d2 = the standard nail diameter given in either Table 9.5.1A or 9.5.2 d1 < d2


August 2001 189

∆P

kdl2nf

Table A10.1Relative Density Values

Visually graded lumber Glued-laminated timberMSR (or MEL) E Grades of S-P-F*

Mean oven-dryrelative density

D Fir-Larch

Hem-Fir

Spruce-Pine-Fir

Northern Species

D Fir-Larch, Hem-Fir†

Hem-Fir†

Spruce-Pine

13 800–16 500 MPa

12 400–13 100 MPa

8300–11 700 MPa

0.50

0.49

0.47

0.46

0.44

0.42

0.35

*For species of MSR or MEL lumber other than S-P-F, use visually graded lumber values.†The outer laminations of Hem-Fir glulam consist of Douglas Fir-Larch; for this reason, use the relative density of DouglasFir-Larch for Hem-Fir glulam where the fasteners do not pass through the inner laminations. In all other cases, use thevisually graded lumber Hem-Fir density values.Notes:(1) Relative density values are listed above on a mean oven-dry weight and volume basis. In the fastenings equations,these values are modified to relate fastening capacities to fifth percentile density values on a 15% moisture volume basis.(2) Where fastening capacity for bolts, drift pins, or lag screws in wood of a given relative density is not available, usethe capacity in a lower relative density wood, or calculate capacity using the equations given in the Standard.

A10.6.3.3 Lateral Deformation of Lag Screw JointsFor a specified load, P, the lateral deformation of a lag screw joint may be estimated from

where) = lateral deformation, mmP = specified load on the connection, Nk = lateral slip resistance of lag screw, MPa

for 2 = 0E (parallel-to-grain loading)k = kP = (5.04G–0.29)JYJSFJG

for 2 = 90E (perpendicular-to-grain loading)k = kQ = (5.04G–0.29)JQJSFJG

for 0E < 2 < 90E (angle-to-grain loading)k = kPkQ/(kPsin

22+kQcos22)JY = side plate factor

= 1.5 for steel side platesJQ = perpendicular-to-grain load factor (Table A10.6.3.3)JG = factor for groups of fastenings (Tables 10.2.2.3.4A and 10.2.2.3.4B)G = mean relative density (Table A10.1)d = lag screw diameter, mml2 = length of penetration into main member, mm (Clause 10.6.3)nf = number of lag screws in connection

Note: Lag screws loaded laterally tend to reach a point of permanent deformation at about 0.8 to 1.0 mm. This limitshould be avoided to prevent permanent deformation.


190 August 2001

Pt

XtftnSQ(nR1)

KtβtEt

Pv

XvFvLp[S

p(nc1) 50]

Kvβvγ

Table A10.6.3.3Factor JQ for Perpendicular-to-Grain

Loading of Lag Screws

Lag screw diameter, in JQ

3/16 1/4 5/16 3/8 7/16 1/2 5/8 3/4 7/81

1.000.970.850.760.710.650.600.550.520.50

A10.7.2.3 Analysis of Timber Rivet (Glulam Rivet) Joints: GeneralMethod for Douglas Fir-L GlulamNote: The following design formulae are derived from tests on timber rivet (also known as glulam rivet) joints inDouglas Fir-Larch glulam. For joints in other species of glulam, or in sawn timber, reduce the resulting strength resistanceby the factor H in Clause 10.7.2.

A10.7.2.3.1 Parallel-to-Grain LoadingIn Clause 10.7.2.3, the lateral strength resistance for wood capacity, pw, kN, per joint parallel to grain isequal to the least value of the tensile strength of the timber, Pt, and the shear strength of the timber, Pv,determined as follows:

whereXt = adjustment factor for tension parallel = 1.41ftn = specified strength in tension parallel to grain at net section (Table 6.3), MPaSQ = rivet spacing perpendicular to grain (Figure 10.7.1.7), mmnR = number of rows of rivetsKt = constant depending on nR and nC (Table A10.7.2.3A)nC = number of rivets per row$t = constant depending on Sp, SQ, and nR (Table A10.7.2.3B)Sp = rivet spacing parallel to grain (Figure 10.7.1.7), mmEt = constant depending on b and Lp (Table A10.7.2.3C)b = member dimension, mm; for connections with steel plates on opposite sides, member dimension

is the width of the member; for connections having only one plate, member dimension is twicethe width of the member.

whereXv = adjustment factor for shear = 1.48Fv = fv (0.15 + 4.35 CV), MPafv = longitudinal shear strength, MPa (Table 6.3)CV = ($1 + $2$3)

–0.2

$ ' & %& &

$ '&

& &&

&

µ − µ β = +

p

5b5 1.9–0.95L

3 p3 1 1–

L 1– exp2 50

' &&

&&

'&

$ &

'$ &

&



)

a = end distance (Figure 10.7.1.7), mmL = rivet penetration (Figure 10.7.1.1)p

K = constant depending on n and n (Table A10.7.2.3D)v R C

$ = constant depending on S and S (Table A10.7.2.3E)v p Q

( = 90.5 + 5.4 Lp

Note: For cases where b # 175 mm, S = 40 mm, S = 25 mm, and L $ 55 mm, P will be greater than P .p Q p v t

A10.7.2.3.2 Perpendicular-to-Grain LoadingIn Clause 10.7.2.5, the lateral strength resistance for wood capacity perpendicular to grain, q , may bew

determined from

whereX = adjustment factor for tension perpendicular = 1.45tp

f = specified strength in tension perpendicular to grain, MPa (Table 6.3) tp

K = constant depending on n and n (Table A10.7.2.3F)tp R C

$ = constant depending on S and S (Table A10.7.2.3G)tp p Q

and the value of the factor, C , may be determined fromt

where$ = constant depending on e /(n –1)S (Table A10.7.2.3H)D p C Q

e = unloaded edge distance, mm (Figure 10.7.1.7)p



Table A10.7.2.3AValues of Kt

Rivets Number of rows, nperrow, nC

R

2 4 6 8 10 12 14 16 18 20

2 0.75 1.16 1.37 1.47 1.51 1.54 1.57 1.61 1.64 1.64 4 0.51 0.88 1.08 1.17 1.22 1.26 1.30 1.35 1.38 1.38 6 0.38 0.71 0.89 0.97 1.02 1.06 1.11 1.16 1.18 1.18 8 0.30 0.60 0.75 0.84 0.89 0.93 0.97 1.02 1.05 1.0510 0.26 0.52 0.66 0.74 0.79 0.82 0.87 0.91 0.94 0.9412 0.23 0.47 0.59 0.66 0.71 0.75 0.78 0.82 0.85 0.8514 0.21 0.42 0.54 0.60 0.65 0.68 0.72 0.75 0.77 0.7716 0.20 0.38 0.49 0.56 0.60 0.63 0.67 0.69 0.71 0.7118 0.18 0.35 0.45 0.52 0.56 0.59 0.62 0.65 0.66 0.6720 0.17 0.32 0.42 0.49 0.53 0.56 0.59 0.61 0.63 0.6422 0.16 0.30 0.40 0.46 0.51 0.54 0.56 0.58 0.60 0.6124 0.15 0.29 0.38 0.45 0.49 0.52 0.53 0.55 0.57 0.5826 0.14 0.28 0.36 0.42 0.46 0.50 0.51 0.52 0.54 0.55

Table A10.7.2.3BValues of $t

S , S ,p

mm mm 2 4 6 8 10 12 14 16 18 20Q

Number of rows, nR

25 12.5 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00

32 12.5 0.94 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93

40 12.5 0.87 0.87 0.87 0.87 0.87 0.87 0.88 0.87 0.87 0.87

50 12.5 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75

15.0 1.11 1.06 1.04 1.02 1.02 1.01 1.01 1.01 1.01 1.0125.0 1.68 1.36 1.23 1.14 1.09 1.08 1.08 1.06 1.04 1.0332.0 2.03 1.54 1.34 1.22 1.14 1.10 1.09 1.07 1.06 1.0540.0 2.37 1.72 1.46 1.29 1.18 1.14 1.12 1.10 1.08 1.06

15.0 1.05 0.99 0.97 0.95 0.95 0.94 0.94 0.94 0.94 0.9425.0 1.58 1.27 1.15 1.07 1.02 1.00 1.00 0.98 0.98 0.9732.0 1.90 1.44 1.26 1.14 1.06 1.02 1.01 0.99 0.98 0.9840.0 2.23 1.61 1.36 1.21 1.11 1.06 1.04 1.02 1.00 1.00

15.0 0.97 0.92 0.90 0.89 0.88 0.88 0.88 0.88 0.88 0.8825.0 1.48 1.18 1.07 1.00 0.96 0.93 0.92 0.92 0.91 0.9032.0 1.78 1.34 1.17 1.06 0.99 0.96 0.94 0.93 0.93 0.9240.0 2.08 1.50 1.27 1.13 1.04 0.99 0.97 0.95 0.94 0.93

15.0 0.84 0.79 0.77 0.76 0.76 0.76 0.76 0.75 0.75 0.7525.0 1.27 1.00 0.91 0.85 0.81 0.79 0.79 0.78 0.78 0.7732.0 1.54 1.14 1.00 0.91 0.85 0.82 0.82 0.80 0.80 0.7940.0 1.80 1.27 1.09 0.97 0.89 0.86 0.85 0.83 0.82 0.81


August 2001 193

Et

2αtγ

LP

1.0 0.155 3b

2LP

2

for b < 6Lp

Table A10.7.2.3CValues of Et*

Rivetpenetration,Lp, mm

Width of glulam member, b (mm)

80 130 175 215 265 315 365

305580

24.025.325.6

18.621.222.7

16.818.420.3

16.816.418.5

16.814.816.7

16.814.115.2

16.814.014.1

*For intermediate sawn timber widths, straight line interpolation or the following formula may be used to calculate Et:

where( = 90.5 + 5.4Lp

"t = 1.0 for b $6Lp

Table A10.7.2.3DValues of Kv

Rivetsperrow, nC

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

2 4 6 8101214161820222426

2.232.312.352.362.372.362.352.342.332.322.312.302.30

1.611.691.731.761.781.781.781.781.781.781.781.781.78

1.151.221.271.301.321.331.341.341.351.351.351.351.35

0.810.880.930.960.981.001.011.021.021.031.031.031.03

0.600.660.700.730.750.770.780.790.800.800.800.800.80

0.480.530.570.600.620.630.640.650.660.660.660.660.66

0.400.450.480.510.530.550.560.570.570.570.570.570.57

0.320.370.400.430.450.460.470.480.480.480.480.480.48

0.250.300.330.360.380.390.400.400.400.400.400.400.40

0.190.240.270.300.310.320.330.330.340.340.340.340.35


194 August 2001

Table A10.7.2.3EValues of $v

Sp,mm

SQ,mm

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

25 12.515.025.032.040.0

1.001.000.970.950.94

1.000.970.810.720.63

1.000.950.710.570.43

1.000.950.670.510.34

1.000.940.630.440.26

1.000.940.620.430.24

1.000.940.610.420.23

1.000.930.600.400.20

1.000.930.580.380.17

1.000.930.570.350.13

32 12.515.025.032.040.0

1.061.051.021.021.02

1.061.020.840.750.68

1.061.000.710.580.46

1.060.990.660.500.36

1.050.970.600.420.27

1.050.970.580.400.25

1.040.960.560.380.24

1.040.950.540.360.21

1.030.940.510.330.18

1.020.930.490.300.14

40 12.515.025.032.040.0

1.111.111.071.101.11

1.121.080.840.790.73

1.121.050.680.600.48

1.111.030.610.510.38

1.101.010.530.420.27

1.091.000.490.400.26

1.080.980.450.370.24

1.070.970.420.340.22

1.060.960.380.310.18

1.050.940.350.270.14

50 12.515.025.032.040.0

1.221.231.261.271.29

1.241.211.040.930.83

1.241.180.890.710.53

1.221.150.820.610.41

1.201.120.740.520.29

1.181.100.720.500.27

1.161.080.710.480.25

1.141.060.680.460.23

1.121.040.650.420.19

1.101.020.620.390.15

Table A10.7.2.3FValues of Ktp

Rivets perrow, nC

Number of rows, nR

2 4 6 8 10

2 4 6 8101214161820

0.290.220.170.130.110.090.070.060.050.05

0.670.500.390.310.250.210.180.150.130.12

0.880.680.540.440.360.310.260.230.200.18

0.980.780.630.520.440.370.320.280.250.22

1.040.850.690.580.480.410.360.310.280.25



Table A10.7.2.3GValues of $tp

S , S ,Q

mm mm 2 4 6 8 10p

Number of rows, nR

15 25 1.29 1.25 1.24 1.23 1.23

25 25 1.00 1.00 1.00 1.00 1.00

32 25 0.82 0.84 0.85 0.86 0.86

40 25 0.63 0.68 0.70 0.71 0.71

40 1.76 1.61 1.49 1.45 1.40

32 1.18 1.13 1.10 1.09 1.0740 1.36 1.27 1.20 1.17 1.1450 1.72 1.53 1.40 1.34 1.28

32 0.97 0.96 0.94 0.93 0.9340 1.12 1.07 1.03 1.00 0.9850 1.42 1.29 1.20 1.15 1.10

32 0.75 0.77 0.78 0.77 0.7640 0.87 0.86 0.84 0.83 0.8250 1.11 1.04 0.98 0.95 0.92

Table A10.7.2.3HValues of $D

e e p

$ $(n –1)S (n –1)SD

p

DC Q C Q

0.1 0.275 1.0 0.830.2 0.433 1.2 0.880.3 0.538 1.4 0.920.4 0.60 1.6 0.950.5 0.65 1.8 0.970.6 0.69 2.0 0.980.7 0.73 2.4 0.990.8 0.77 2.8 and 1.000.9 0.80 more

Note: For e /[(n –1)S ] between 0.1 and 0.3, $ is given to three significantP C Q D

digits due to the sensitivity in this range.



A10.9.3.2 Lateral Deformation of Nailed and Spiked Wood-to-WoodJointsFor specified loads, P, not greater than n /3, the lateral deformation of nailed and spiked joints may beu

estimated from

) = 0.5dK (P/n )m u1.7

where) = lateral deformation, mmd = nail diameter, mmK = service creep factor (Table A10.9.3.2) m

P = specified load per nail or spike, Nn = unit lateral strength resistance (Table 10.9.4), Nu

Table A10.9.3.2Service Creep Factors, K , for Nail and Spike Jointsm

Load duration Nailed dry, Nailed wet, Nailed wet,class loaded dry loaded dry loaded wet

Moisture condition

Permanent 1.5 2.0 3.0Standard 1.2 1.5 2.0Short 1.0 1.2 1.5

) A13.2.5.1 Length Adjustment Factor, K , Used to Determine MomentLN

Resistance of Prefabricated Wood I-JoistsThe length adjustment factor is used by manufacturers to develop proprietary I-joist moment resistancevalues and is not intended as an adjustment factor for specific applications. K is taken fromLN

Section 6.3.1.5 of ASTM Standard D 5055 and is the lesser of 1.0 or the value computed as follows:

K = (stress distribution adjustment factor) (L /L) # 1.0LN 1 Z

wherestress distribution adjustment factor = the adjustment of specified strength parallel to grain, f , froma

full-length constant stress (such as a tension test) to the reference stress condition (simple span anduniform load) = 1.15L = gauge length (distance between grips) used in tension tests, parallel to grain, for I-joist flange 1

materialL = nominal I-joist span

= 18 times the joist depthZ = a coefficient (see Table A13.2.5.1) that accounts for the variation in tensile strength of the flange

material


January 2005 197

) Table A13.2.5.1Exponent, Z, used in the Calculation of the

Length Adjustment Factor for Prefabricated Wood I-Joists

Coefficient of variation*†, % Z‡

# 10 0.06

15 0.09

20 0.12

25 0.15

$ 30 0.19

*Coefficient of variation is determined from thefull test data set using the higher coefficient ofvariation attained from the tensile strength offlange material or the tensile strength of endjoints.†Coefficient of variation for tensile strength offlange material is taken as 20% formachine-graded lumber (including SPS-4material) and 25% for visually graded lumber.‡Interpolation between tabular values ispermitted.

O86-01Engineering Designin Wood

CSA Standards Update Service

O86-01August 2001

Title: Engineering Design in WoodPagination: 215 pages (xix preliminary and 196 text), each dated August 2001

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O86-01

CSA Standard

O86-01Engineering Design in Wood

®Registered trade-mark of Canadian Standards Association

Published in August 2001 by Canadian Standards AssociationA not-for-profit private sector organization

178 Rexdale Boulevard, Toronto, Ontario, Canada M9W 1R31-800-463-6727 • 416-747-4044

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ISBN 1-55324-411-7Technical Editor: Mike LottamozaManaging Editor: Gary BurfordProduction Manager: Alison MacIntosh

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© Canadian Standards Association — 2001

All rights reserved. No part of this publication may be reproduced in any form whatsoeverwithout the prior permission of the publisher.


August 2001 iii

Contents

Technical Committee on Engineering Design in Wood ix

Subcommittee on General Design xi

Subcommittee on Sawn Lumber xii

Subcommittee on Glued-Laminated Timber xiii

Subcommittee on Panel Products xiv

Subcommittee on Fastenings xv

Subcommittee on Proprietary Structural Wood Products xvi

Task Force on Seismic Design in Wood xvii

Preface xviii

1. Scope 1

2. Definitions, Symbols, Spacing Dimensions, and Reference Publications 12.1 Definitions 12.2 Symbols 72.3 Spacing Dimensions 102.4 Reference Publications 11

3. Objectives and Design Requirements 143.1 Objective 143.2 Limit States 143.3 Design Requirements 143.3.1 Structural Adequacy 143.3.2 New or Special Systems of Design and Construction 143.3.3 Structural Integrity 143.3.4 Basis of Design 143.3.5 Quality of Work 143.3.6 Design Drawings 14

4. General Design 154.1 Strength and Serviceability Limit States 154.1.1 Method of Analysis 154.1.2 Strength Limit States 154.1.3 Serviceability Limit States 154.1.4 Resistance Factors 154.2 Specified Loads, Load Effects, and Load Combinations 154.2.1 Buildings 154.2.2 Other Structures 164.2.3 Specified Loads 164.2.4 Load Effects and Combinations 164.3 Conditions and Factors Affecting Resistance 17

O86-01 © Canadian Standards Association

iv August 2001

4.3.1 General 174.3.2 Load Duration Factor, KD 174.3.3 Service Condition Factor, KS 184.3.4 Preservative and Fire-Retardant Treatment Factor, KT 184.3.5 System Factor, KH 184.3.6 Size Factor, KZ 184.3.7 Lateral Stability Factor, KL 194.3.8 Reduction in Cross-Section 194.4 Resistance to Seismic Loads 194.5 Serviceability Requirements 194.5.1 Modulus of Elasticity 194.5.2 Elastic Deflection 194.5.3 Permanent Deformation 194.5.4 Ponding 194.5.5 Vibration 20

5. Sawn Lumber 205.1 Scope 205.2 Materials 205.2.1 Identification of Lumber 205.2.2 Lumber Grades and Categories 215.2.3 Finger-Joined Lumber 225.2.4 Remanufactured Lumber 225.2.5 Mixed Grades 225.3 Specified Strengths 225.3.1 Visually Stress-Graded Lumber 225.3.2 Machine Stress-Rated and Machine Evaluated Lumber 235.4 Modification Factors 285.4.1 Load Duration Factor, KD 285.4.2 Service Condition Factor, KS 285.4.3 Treatment Factor, KT 285.4.4 System Factor, KH 295.4.5 Size Factor, KZ 295.5 Strength and Resistance 315.5.1 General 315.5.2 Sizes 315.5.3 Continuity 315.5.4 Bending Moment Resistance 315.5.5 Shear Resistance 325.5.6 Compressive Resistance Parallel to Grain 355.5.7 Compressive Resistance Perpendicular to Grain 395.5.8 Compressive Resistance at an Angle to Grain 405.5.9 Tensile Resistance Parallel to Grain 405.5.10 Resistance to Combined Bending and Axial Load 415.5.11 Decking 415.5.12 Preserved Wood Foundations 425.5.13 Sawn Lumber Design for Specific Truss Applications 43

6. Glued-Laminated Timber (Glulam) 456.1 Scope 456.2 Materials 456.2.1 Stress Grades 456.2.2 Appearance Grades 456.3 Specified Strengths 45


August 2001 vii

10.2.2 Bolts, Lag Screws, Split Rings, and Shear Plate Connectors (General Requirements) 10110.3 Split Ring and Shear Plate Connectors 10710.3.1 General 10710.3.2 Service Condition Factor 10810.3.3 Distance Factors 10810.3.4 Lumber Thickness 11310.3.5 Lag Screw Connector Joints 11310.3.6 Lateral Resistance 11410.4 Bolts 11510.4.1 General 11510.4.2 Member Thickness 11610.4.3 Placement of Bolts in Joints 11610.4.4 Lateral Resistance 11810.4.5 Combined Lateral and Axial Resistance 12010.5 Drift Pins 12010.5.1 General 12010.5.2 Prebored Holes 12010.5.3 Drift Pin Points 12010.5.4 Drift Pin Length 12010.5.5 Size and Placement of Drift Pins in Joints 12010.5.6 Lateral Resistance 12110.6 Lag Screws 12210.6.1 General 12210.6.2 Placement of Lag Screws in Joints 12210.6.3 Penetration of Lag Screws 12210.6.4 Side Members 12310.6.5 Withdrawal Resistance 12310.6.6 Lateral Resistance 12310.7 Timber Rivets (also known as Glulam Rivets) 12510.7.1 General 12510.7.2 Lateral Resistance 12910.7.3 Withdrawal Resistance 13010.8 Truss Plates 14210.8.1 General 14210.8.2 Design 14310.8.3 Factored Resistance of Truss Plates 14510.8.4 Lateral Slip Resistance 14710.9 Nails and Spikes 14810.9.1 General 14810.9.2 Joint Configuration 14810.9.3 Joint Design 15110.9.4 Lateral Resistance 15110.9.5 Withdrawal Resistance 15210.10 Joist Hangers 15410.10.1 General 15410.10.2 Design 15510.10.3 Factored Resistance of Joist Hangers 155

11. Timber Piling 15511.1 Scope 15511.2 Materials 15611.2.1 Preservative Treatment 15611.2.2 Untreated Piling 15611.3 Specified Strengths 156


viii August 2001

11.4 Modification Factors 15611.5 Strength and Resistance 15611.5.1 General 15611.5.2 Piles as Compression Members 15611.5.3 Effective Length 15611.5.4 Embedded Portion 15611.5.5 Unembedded Portion 157

12. Pole-Type Construction 15712.1 Scope 15712.1.1 Round Poles 15712.1.2 Sawn Timbers 15712.2 Materials 15812.2.1 Preservative Treatment 15812.2.2 Short Poles 15812.3 Specified Strengths 15812.4 Modification Factors 15812.5 Strength and Resistance 15812.5.1 General 15812.5.2 Poles as Compression Members 15812.5.3 Poles as Bending Members 159

13. Proprietary Structural Wood Products 15913.1 Scope 15913.2 Prefabricated Wood 3-Joists 15913.2.1 General 15913.2.2 Materials 15913.2.3 Specified Strengths and Moduli of Elasticity 16013.2.4 Modification Factors 16213.2.5 Strength and Resistance 16313.2.6 Fastenings 16513.3 Type 3 (Proprietary) Design-Rated OSB Panels 16513.3.1 Manufacture 16513.3.2 Panel Identification and Certificates of Conformance 16513.3.3 Basic Structural Capacities 16513.3.4 Specified Capacities 16513.3.5 Design Methods 16613.4 Structural Composite Lumber Products 16613.4.1 General 16613.4.2 Adhesives 16613.4.3 Specified Strengths and Moduli of Elasticity 16613.4.4 Modification Factors 16713.4.5 Strength and Resistance 16813.4.6 Fastenings 171

Appendix A — Additional Information and Alternative Procedures 173


August 2001 9

KSb = service condition factor for bending

KSc = service condition factor for compression parallel to grain

KScp = service condition factor for compression perpendicular to grain

KSE = service condition factor for modulus of elasticity

KSF = service condition factor for fastening

KSt = service condition factor for tension parallel to grain

KStp = service condition factor for tension perpendicular to grain

KSv = service condition factor for shear

KT = treatment factor (Clause 4.3.4.1)

KX = curvature factor for glued-laminated timber (Clause 6.5.6.5.2)

KZ = size factor (Clause 5.4.5 and Table 5.4.5)

KZb = size factor for bending for sawn lumber

KZbg = size factor for bending for glued-laminated timber (Clause 6.5.6.5.1)

KZc = size factor for compression for sawn lumber (Clauses 5.5.6.2.3 and 5.5.13.3.3)

KZcg = size factor for compression for glued-laminated timber (Clause 6.5.8.4.2)

KZcp = size factor for bearing (Clauses 5.5.7.5 and 6.5.9.2)

KZt = size factor for tension for sawn lumber

KZtp = size factor for tension perpendicular to grain for glued-laminated timber (Table 6.5.6.6.1)

KZv = size factor for shear for sawn lumber (Clause 5.4.5.3)

L = length, mm

Le = effective length, mm

Lp = length of penetration of fastening into main member, mm

= span, mm

Mf = factored bending moment, N•mm

Mr = factored bending moment resistance, N•mm

mp = specified strength capacity of structural panels in bending, N•mm/mm (Tables 7.3A, 7.3B, 7.3C,and 7.3D)

Nr = factored compressive resistance at an angle to grain, N; or

= factored lateral strength resistance of fastenings at an angle to grain, N or kN

Nrs = factored lateral slip resistance of fastenings at an angle to grain, N

Ns = lateral slip resistance of fastenings at an angle to grain, N

Nu = lateral strength resistance of fastenings at an angle to grain, N or kN

nF = number of fastenings in a group

Pf = factored axial load in compression, N

Pr = factored compressive resistance parallel to grain, N; or

= factored lateral strength resistance of fastenings parallel to grain, N or kN

Prs = factored lateral slip resistance of fastenings parallel to grain, N


10 August 2001

Prw = factored withdrawal resistance of fastenings from side grain, N

Pu = lateral strength resistance of fastenings parallel to grain, N or kN

pp = specified strength capacity of structural panels in axial compression, N/mm (Tables 7.3A, 7.3B,7.3C, and 7.3D)

Qr = factored compressive resistance perpendicular to grain or to plane of plies, N; or

= factored lateral strength resistance of fastenings perpendicular to grain, N or kN

Qrs = factored lateral slip resistance of fastenings perpendicular to grain, N

Qu = lateral strength resistance of fastenings perpendicular to grain, N or kN

qp = specified strength capacity of structural panels in bearing, MPa (Tables 7.3A, 7.3B, 7.3C, and 7.3D)

R = radius of curvature at centreline of member, mm (Figure 6.5.6.6.3)

S = section modulus, mm3

Tf = factored axial load in tension, N

Tr = factored tensile resistance parallel to grain, N

tp = specified strength capacity of structural panels in axial tension, N/mm (Tables 7.3A, 7.3B, 7.3C,and 7.3D)

Vf = factored shear force, N

Vhd = factored basic shear resistance calculated with Jhd = 1.0, kN (Clause 9.4.5)

Vr = factored shear resistance, N; or

= factored shear-through-thickness resistance of structural panels, N

Vrp = factored planar shear resistance of structural panels, N

Vrs = factored shear resistance of a shearwall segment, kN (Clause 9.5)

vp = specified strength capacity of structural panels in shear-through-thickness, N/mm (Tables 7.3A,7.3B, 7.3C, and 7.3D)

vpb = specified strength capacity of structural panels in planar shear (due to bending), N/mm(Tables 7.3A, 7.3B, 7.3C, and 7.3D)

vpf = specified strength capacity of structural panels in planar shear (due to in-plane forces), MPa(Tables 7.3A, 7.3B, 7.3C, and 7.3D)

Wf = factored total load, N

w = specified total uniformly distributed load, kN/m2

X = factors affecting capacities of plywood and plywood assemblies, used with appropriate subscripts(Clause 8)

Z = volume, m3

( = importance factor (Clause 4.2.4.4)

φ = resistance factor

R = load combination factor (Clause 4.2.4.3)

2.3 Spacing DimensionsFor the purpose of this Standard, the following apply:(a) Centre-to-centre member spacing dimensions may be used interchangeably:

(i) 300 mm and 305 mm;


August 2001 11

(ii) 400 mm and 406 mm; and(iii) 600 mm and 610 mm.

(b) Panel dimensions may be used interchangeably:(i) 1200 mm and 1220 mm; and(ii) 2400 mm and 2440 mm.

2.4 Reference PublicationsThis Standard refers to the following publications and where such reference is made it shall be to theedition listed below, including all amendments published thereto.

CSA StandardsB111-1974 (R1998), Wire Nails, Spikes, and Staples;

G40.20/G40.21-98,General Requirements for Rolled or Welded Structural Quality Steel/Structural Quality Steel;

CAN/CSA-O15-90 (R2001), Wood Utility Poles and Reinforcing Stubs;

CAN3-O56-M79 (R2001), Round Wood Piles;

O80 Series-97, Wood Preservation;

O80.15-97,Preservative Treatment of Wood for Building Foundation Systems, Basements, and Crawl Spaces byPressure Processes;

O112 Series-M1977 (R2001),CSA Standards for Wood Adhesives;

O112.6-M1977 (R2001), Phenol and Phenol-Resorcinol Resin Adhesives for Wood (High-Temperature Curing);

O112.7-M1977 (R2001), Resorcinol and Phenol-Resorcinol Resin Adhesives for Wood (Room- and Intermediate-Temperature Curing);

O121-M1978 (R2001), Douglas Fir Plywood;

CAN/CSA-O122-M89 (R2001), Structural Glued-Laminated Timber;

CAN/CSA-O141-91 (R2001), Softwood Lumber;

O151-M1978 (R2001), Canadian Softwood Plywood;

O153-M1980 (R2001),Poplar Plywood;

CAN/CSA-O177-M89 (R2001), Qualification Code for Manufacturers of Structural Glued-Laminated Timber;


12 August 2001

O322-1976 (R1999), Procedure for Certification of Pressure-Treated Wood Materials for Use in Preserved Wood Foundations;

CAN/CSA-O325.0-92 (R2001),Construction Sheathing;

O437 Series-93 (R2001),Standards on OSB and Waferboard;

O437.0-93 (R2001), OSB and Waferboard;

O452 Series-94 (R2001),Design Rated OSB;

O452.0-94 (R2001), Design Rated OSB: Specifications;

S307-M1980 (R2001),Load Test Procedure for Wood Roof Trusses for Houses and Small Buildings;

S347-99, Method of Test for Evaluation of Truss Plates Used in Lumber Joints;

CAN/CSA-S406-92 (R1998), Construction of Preserved Wood Foundations.

Standard Practice Relating Specified Strengths of Structural Members to Characteristic Structural Properties. CSA Technical Committee on Engineering Design in Wood, November 2000. Available free of charge atwww.csa.ca.

ANSI/ASME* Standard B18.2.1-1996,Square and Hex Bolts and Screws, Inch Series.

ASTM† StandardsA 36/A 36M-00a, Carbon Structural Steel;

A 47/A 47M-99, Ferritic Malleable Iron Castings;

A 307-00, Carbon Steel Bolts and Studs, 60 000 PSI Tensile Strength;

A 653/A 653M-00,Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process;Note: ASTM Standards A 653/A 653M replace ASTM Standards A 446/A 446M. Their chemical and mechanicalrequirements are the same.C 36/C 36M-99,Gypsum Wallboard;

C 1002-00,Steel Self-Piercing Tapping Screws for the Application of Gypsum Panel Products or Metal Plaster Bases toWood Studs or Steel Studs;


August 2001 13

D 1761-88 (2000),Mechanical Fasteners in Wood;

D 5055-00,Establishing and Monitoring Structural Capacities of Prefabricated Wood I-Joists;

D 5456-99a,Evaluation of Structural Composite Lumber Products;

D 5457-93 (1998),Computing the Reference Resistance of Wood-Based Materials and Structural Connections for Load andResistance Factor Design;

E 8-00b,Standard Test Methods for Tension Testing of Metallic Materials.

Canadian Geotechnical Society PublicationCanadian Foundation Engineering Manual, 1992.

Canadian Wood CouncilCWC, Commentary, 2001 (in Wood Design Manual).

National Research Council CanadaCCMC Registry of Product Evaluations (published annually);

National Building Code of Canada, 1995;

User’s Guide — NBC 1995 Structural Commentaries (Part 4).

NIST‡ StandardPS2-92,Performance Standard for Wood-Based Structural-Use Panels.

NLGA§ PublicationsStandard Grading Rules for Canadian Lumber, 2000;

SPS 1-2000, Special Products Standards on Finger-Joined Structural Lumber;

SPS 2-2000, Special Products Standards on Machine Stress-Rated Lumber.

SAE** PublicationSAE Handbook, 2000.

Truss Plate Institute of CanadaTPIC-1996, Truss Design Procedures and Specifications for Light Metal Plate Connected Wood Trusses.

*American National Standards Institute/American Society of Mechanical Engineers.†American Society for Testing and Materials.‡National Institute of Standards and Technology.§National Lumber Grades Authority.**Society of Automotive Engineers.


14 August 2001

3. Objectives and Design Requirements

3.1 ObjectiveThe objective of the provisions in this Standard is the achievement of acceptable assurances that thestructure, when correctly designed and built, will be fit for the intended use.

3.2 Limit StatesThe structure or portion thereof is considered fit for use when the structure, its components, and itsconnections are designed such that the requirements of Clauses 3.3, 4.1.2, and 4.1.3 are satisfied.

3.3 Design Requirements

3.3.1 Structural AdequacyAll members shall be so framed, anchored, tied, and braced together as to provide the strength andrigidity necessary for the purpose for which they are designed. All structural members shall be ofadequate size and quality to carry all loads and other forces that can be reasonably expected to act uponthem during construction and use without exceeding the strength or serviceability limit states.

3.3.2 New or Special Systems of Design and ConstructionNew or special systems of design or construction of wood structures or structural elements not alreadycovered by this Standard may be used where such systems are based on analytical and engineeringprinciples, or reliable test data, or both, that demonstrate the safety and serviceability of the resultingstructure for the purpose intended.

3.3.3 Structural IntegrityThe general arrangement of the structural system and the interconnection of its members shall providepositive resistance to widespread collapse of the system due to local failure.

3.3.4 Basis of DesignDesign in accordance with this Standard is based on the assumption that(a) the specified loads are realistic in size, kind, and duration;(b) the wood product is normal for its species, kind, and grade;(c) consideration is given to service conditions, including possible deterioration of members andcorrosion of fastenings;(d) the temperature of the wood does not exceed 50EC, except for occasional exposures to 65EC;(e) the design is competent, fabrication and erection are good, grading and inspection are reliable, andmaintenance is normal; and(f) wood products are used as graded or manufactured for a designated end use.

3.3.5 Quality of WorkThe quality of work in fabrication, preparation, and installation of materials shall conform throughout toaccepted good practice.

3.3.6 Design Drawings

3.3.6.1Where design drawings are required they shall be drawn to a scale adequate to convey the requiredinformation. The drawings shall show a complete layout of the structure or portion thereof that is thesubject of the design, with members suitably designated and located, including dimensions and detaileddescriptions necessary for the preparation of shop and erection drawings. Governing heights, columncentres, and offsets shall be dimensioned.


August 2001 15

3.3.6.2Design drawings shall designate the design standards used, as well as material or product standardsapplicable to the members and details depicted.

3.3.6.3When needed for the preparation of shop drawings, the governing loads, reactions, shears, moments,and axial forces to be resisted by all members and their connections shall be shown on drawings orsupplemental material, or both.

3.3.6.4If camber is required for beams, girders, or trusses, the magnitude of such camber shall be specified onthe design drawings.

4. General Design

4.1 Strength and Serviceability Limit States

4.1.1 Method of AnalysisThe load effect on all members and connections shall be determined in accordance with recognizedmethods of analysis generally based on assumptions of elastic behaviour.

4.1.2 Strength Limit StatesDesign for strength limit states shall include(a) establishing the value of the effect of the factored loads for the load combinations specified inClause 4.2; and(b) confirming by rational means that for each load effect in Item (a), the factored load effect does notexceed the corresponding factored resistance, as determined in accordance with the appropriate clausesof this Standard.

4.1.3 Serviceability Limit StatesDesign for serviceability limit states shall include(a) establishing the value of the effect of the specified loads for the load combinations specified inClause 4.2; and(b) confirming by rational means that for each load effect in Item (a), the structural effect falls within thelimits specified in the appropriate clauses of this Standard.

4.1.4 Resistance FactorsThe resistance factors, φ, are given in the appropriate sections of this Standard for all applicable limitstates for wood members and fastenings.

4.2 Specified Loads, Load Effects, and Load Combinations

4.2.1 BuildingsExcept as provided for in Clause 4.2.2, the specified loads, load effects, and combinations to beconsidered in the design of a building and its elements shall be those given in Clauses 4.2.3 and 4.2.4.Note: Specified loads, load effects, and combinations specified herein are in accordance with the provisions of theNational Building Code of Canada, 1995, its Structural Commentaries on Part 4, and the Canadian FoundationEngineering Manual.


16 August 2001

4.2.2 Other StructuresWhere load requirements other than those in Clause 4.2.1 are specified, the appropriateness of theapplicable factored resistance in this Standard shall be considered.

4.2.3 Specified LoadsSpecified loads shall include the following wherever applicable, and minimum specified values of theseloads shall be increased to account for dynamic effects where applicable:(a) D — dead load due to weight of members; the weight of all materials of construction incorporatedinto the building to be supported permanently by the member, including permanent partitions andallowance for nonpermanent partitions; the weight of permanent equipment; forces due to prestressing; (b) E — live load due to earthquake;(c) L — live load due to static or inertial forces arising from intended use and occupancy (includesvertical loads due to cranes); snow, ice, and rain; earth and hydrostatic pressure;(d) W — live load due to wind; and(e) T — loads due to contraction or expansion caused by temperature changes, shrinkage, moisturechanges, creep in component materials, movement due to differential settlement, or combinationsthereof.

4.2.4 Load Effects and Combinations

4.2.4.1 Combinations Not Including Earthquake For load combinations not including earthquake, the effect of factored loads is the structural effect due tothe specified loads multiplied by load factors, ", defined in Clause 4.2.4.2, a load combination factor, Q,defined in Clause 4.2.4.3, and an importance factor, (, defined in Clause 4.2.4.4, and the factored loadcombination shall be taken as

"DD + (Q["LL + "WW + "TT]

4.2.4.2 Load Factors (")Load factors, ", for the strength limit states shall be taken as"D = 1.25, except that when the dead load resists overturning, uplift, or reversal of load, "D = 0.85;"L = 1.50;"W = 1.50; and"T = 1.25.Load factors, ", for serviceability limit states shall be 1.00.

4.2.4.3 Load Combination Factor (Q)The load combination factor, Q, shall be taken as(a) 1.00 when only one of L, W, and T acts;(b) 0.70 when two of L, W, and T act;(c) 0.60 when all of L, W, and T act.The most unfavourable effect shall be determined by considering L, W, and T acting alone or incombination.

4.2.4.4 Importance Factor (()The importance factor, (, for strength limit states shall be not less than 0.80 for structures where it canbe shown that collapse is not likely to cause injury or other serious consequences, and 1.00 for all otherstructures. The importance factor, (, for serviceability limit states shall be 1.00.Note: Examples of buildings where it can be shown that collapse is not likely to cause injury or other seriousconsequences are buildings of low human occupancy, such as farm buildings, certain temporary facilities, and minorstorage facilities.


August 2001 17

4.2.4.5 Combinations Including EarthquakeFor load combinations including earthquake, the factored load combinations shall be taken as1.0D + ((1.0E); and either(a) for storage and assembly occupancies, 1.0D + ((1.0L + 1.0E); or(b) for all other occupancies, 1.0D + ((0.5L + 1.0E).

4.3 Conditions and Factors Affecting Resistance

4.3.1 GeneralSpecified strengths and capacities for materials and fastenings shall be multiplied by the modificationfactors in this clause and the appropriate materials or fastening clauses.Note: The basis for derivation of specified strengths for sawn lumber members is described in CSA Special PublicationStandard Practice Relating Specified Strengths of Structural Members to Characteristic Structural Properties. Theprinciples described therein have also been used to guide derivations for other products in this Standard.


4.3.2.1 Specified Strengths and CapacitiesThe specified strengths and capacities given in this Standard are based on the standard-term duration ofthe specified loads.

4.3.2.2 Load Duration FactorExcept as specified in Clause 4.3.2.3, the specified strengths and capacities shall be multiplied by a loadduration factor, KD, in accordance with Table 4.3.2.2, but not exceeding 1.15.

Table 4.3.2.2Load Duration Factor, KD

Duration of loading KD Explanatory notes

Short term 1.15 Short-term loading means that condition of loading where the durationof the specified loads is not expected to last more than 7 dayscontinuously or cumulatively throughout the life of the structure. Examples include wind loads, earthquake loads, falsework, andformwork, as well as impact loads.

Standard term 1.00 Standard term means that condition of loading where the duration ofspecified loads exceeds that of short-term loading, but is less thanpermanent loading. Examples include snow loads, live loads due to occupancy, wheelloads on bridges, and dead loads in combination with all of the above.

Permanent 0.65 Permanent duration means that condition of loading under which amember is subjected to more or less continuous specified load. Examples include dead loads or dead loads plus live loads of suchcharacter that they are imposed on the member for as long a period oftime as the dead loads themselves. Such loads include those usuallyoccurring in tanks or bins containing fluids or granular material, loadson retaining walls subjected to lateral pressure such as earth, and floorloads where the specified load may be expected to be continuouslyapplied, such as those in buildings for storage of bulk materials. Loadsdue to fixed machinery should be considered to be permanent.

Note: Duration of load may require professional judgment by the designer. Explanatory notes in this tableprovide guidance to designers about the types of loads and load combinations for which each modificationfactor should be applied.


18 August 2001

KD

1.0 0.50 logD

L0.65

4.3.2.3 Permanent Load FactorFor standard-term loads where D is greater than L, the permanent load factor may be used, or the factormay be calculated as

whereD = specified dead loadL = specified live load

4.3.2.4 Combined LoadsWhen the total specified load is made up of loads acting for different durations, the design shall be basedon the most severe combination. The appropriate load duration factor shall be taken into account foreach load combination.

4.3.3 Service Condition Factor, KSWhere materials or fastenings are used in service conditions other than dry, specified strengths andcapacities shall be multiplied by the service condition factor, KS, in the appropriate materials or fasteningclauses.

4.3.4 Preservative and Fire-Retardant Treatment Factor, KT

4.3.4.1 GeneralExcept as permitted in Clause 4.3.4.4, specified strengths and capacities shall be multiplied by thetreatment factor, KT, in the appropriate materials or fastenings clause.

4.3.4.2 Preservative TreatmentWhen conditions conducive to decay or other deterioration are likely to occur in the case of permanentstructures, wood should be pressure-treated with preservative in accordance with the requirements ofthe CSA Standard O80 Series. If possible, all boring, grooving, cutting, and other fabrication should becompleted before treatment. Fabrication that is carried out after pressure treatment shall be treatedlocally in accordance with the CSA Standard O80 Series.

4.3.4.3 Untreated WoodUntreated wood in permanent structures shall not be in direct contact with masonry, concrete, or soilwhen moisture transfer can occur. Any method that eliminates transfer of moisture, e.g., a minimum of10 mm air space around a member in a wall, shall be considered adequate protection.

4.3.4.4 Fire-Retardant TreatmentWhere wood is impregnated with fire-retardant or other strength-reducing chemicals, KT shall bedetermined in accordance with the results of appropriate tests or shall not exceed the value of KT

tabulated in the appropriate clause.

4.3.5 System Factor, KHSpecified strengths may be multiplied by a system factor, KH, as specified in Clauses 5.4.4 and 6.4.3.Note: See Clause A4.3.5 for additional information on system factors.

4.3.6 Size Factor, KZWhere size influences the specified strengths of members, the specified strengths shall be multiplied bythe size factor, KZ, in accordance with Clauses 5.4.5, 6.5.6., 6.5.8, and 6.5.9.Note: See the Canadian Wood Council’s Commentary.


August 2001 19

4.3.7 Lateral Stability Factor, KLThe effect of width-to-depth ratios and of the degree of lateral support on the factored bending momentresistance is specified in Clauses 5.5.4.2 and 6.5.6.4.

4.3.8 Reduction in Cross-Section

4.3.8.1 Net SectionThe net section, obtained by deducting from the gross section the area of all material removed byboring, grooving, dapping, notching, or other means, shall be checked in calculating the strengthcapacity of a member.

4.3.8.2 LimitationIn no case shall the net section be less than 75% of the gross section.

4.4 Resistance to Seismic LoadsThe factored resistance required for seismic loading may be obtained by the use of shearwalls anddiaphragms (Clause 9). Where concentrically braced heavy timber space frames or moment-resistingwood space frames are used to provide seismic resistance, fastenings such as nails, bolts, lag screws, orglulam rivets as specified in Clause 10 shall be used to provide ductile connections.Note: Split rings and shear plates are not generally considered to provide ductile connections.

4.5 Serviceability Requirements

4.5.1 Modulus of ElasticityThe modulus of elasticity for stiffness calculations, ES, shall be taken as

ES = E(KSEKT)

whereE = specified modulus of elasticity, MPaKSE = service condition factorKT = treatment factor

4.5.2 Elastic DeflectionThe elastic deflection of structural members under the specified loads shall not exceed 1/180 of the span. For glued-laminated members having cambers equalling at least dead load deflection, the additionaldeflection due to specified live loads shall not exceed 1/180 of the span. Deflection under the specifiedloads shall be limited to avoid damage to structural elements or attached nonstructural elements.Note: See Clause A4.5.2 for additional information on deflection of a wood frame system under static loads.

4.5.3 Permanent DeformationStructural members that support continuously applied loads in excess of 50% of the total specified loadsshall be designed to avoid excessive permanent deformation. In lieu of a more accurate evaluation ofacceptable deflection limits, an upper limit of 1/360 of the span shall be imposed on the elasticdeflection due to continuously applied loads. Special allowance shall be made in the design wherepermanent deformations can result in unsightly appearance or potential damage to adjacent elements ofthe building or structure.

4.5.4 PondingRoof framing systems shall be investigated by rational analysis to ensure adequate performance underponding conditions unless (a) the roof surface is provided with sufficient slope toward points of free drainage to preventaccumulation of rain water; or


20 August 2001

∆

w< 65

(b) for a simply supported system subjected to a uniformly distributed load, the following condition issatisfied:

whereE) = sum of deflections due to this load, mm, of all the components of the system (decking, secondary

beams, primary beams, etc)w = total uniformly distributed load, kN/m2

4.5.5 VibrationSpecial consideration shall be given to structures subjected to vibration to ensure that such vibration isacceptable for the use of the structure.Note: See Clause A4.5.5 for information on floor vibration. Additional information can be found in the commentary onserviceability criteria for deflections and vibrations in the User’s Guide — NBC 1995 Structural Commentaries (Part 4).

5. Sawn Lumber

5.1 ScopeDesign tables, data, and methods specified in Clause 5 apply only to structural lumber complying withthe requirements of CSA Standard CAN/CSA-O141.

5.2 Materials

5.2.1 Identification of Lumber

5.2.1.1 GeneralDesign in accordance with this Standard is predicated on the use of lumber that is graded in accordancewith the NLGA Standard Grading Rules for Canadian Lumber and identified by the grade stamp of anassociation or independent grading agency in accordance with the provisions of CSA Standard CAN/CSA-O141.Note: A list of approved agencies may be obtained from the Canadian Lumber Standards Accreditation Board.

5.2.1.2 Canadian LumberIn this Standard, Canadian species are designated according to species combinations given inTable 5.2.1.2, which reflects marketing practice. These combinations should be used for general designpurposes.Note: The designer is strongly advised to check availability of species, grade, and sizes before specifying.

5.2.1.3 US LumberFor US commercial species combinations graded in accordance with the National Grading Rule forDimension Lumber, the design data may be determined using the species combination equivalents inTable 5.2.1.3.


August 2001 23

5.3.1.2The specified strengths (MPa) for plank decking shall be derived from Table 5.3.1A using the followinggrade equivalents:

Decking grade Equivalent lumber grade

Select Select StructuralCommercial No. 2

5.3.2 Machine Stress-Rated and Machine Evaluated LumberThe specified strengths (MPa) for machine stress-rated lumber are given in Table 5.3.2. The specifiedstrengths (MPa) for machine evaluated lumber are given in Table 5.3.3. Specified strengths in shear arenot grade-dependent and shall be taken from Table 5.3.1A for the appropriate species.

Table 5.3.1ASpecified Strengths and Modulus of Elasticity for Structural

Joist and Plank, Structural Light Framing, and StudGrade Categories of Lumber (MPa)

Speciesidentification Grade


Longi-tudinalshear,fv

Compression


Modulus ofelasticityParallel

to grain,fc

Perpen-dicularto grain,fcp E E05

D Fir-L SSNo. 1/No. 2No. 3/Stud

16.510.0 4.6

1.119.014.0 4.6

7.010.6 5.8 2.1

12 50011 00010 000

8 5007 0005 500

Hem-Fir SSNo. 1/No. 2No. 3/Stud

16.011.0 7.0

0.917.614.8 7.0

4.6 9.7 6.2 3.2

12 00011 00010 000

8 5007 5006 000

S-P-F SSNo. 1/No. 2No. 3/Stud

16.511.8 7.0

1.014.511.5 7.0

5.3 8.6 5.5 3.2

10 500 9 500 9 000

7 5006 5005 500

Northern SSNo. 1/No. 2No. 3/Stud

10.6 7.6 4.5

0.913.010.4 4.5

3.5 6.2 4.0 2.0

7 500 7 000 6 500

5 5005 0004 000

Note: Tabulated values are based on the following standard conditions:(a) 286 mm larger dimension;(b) dry service conditions; and(c) standard-term duration of load.


24 August 2001

Table 5.3.1BSpecified Strengths and Modulus of Elasticity for Light FramingGrades (MPa) Applicable to Sizes 38 by 38 mm to 89 by 89 mm


Bending atextremefibre,fb

Longi- tudinalshear,fv

Compression Tensionparallelto grain,ft

Modulus ofelasticityParallel

to grain,fc

Perpendicularto grain,fcp

E E05

D Fir-L Const. 13.0 1.9 16.0 7.0 6.6 10 000 5 500

Stand. 7.3 13.1 3.7 9 000 5 000

Hem-Fir Const. 14.3 1.5 16.9 4.6 7.0 10 000 6 000

Stand. 8.0 13.9 3.9 9 000 5 500

S-P-F Const. 15.3 1.7 13.1 5.3 6.2 9 000 5 500

Stand. 8.6 10.8 3.5 8 000 5 000

Northern Const. 9.9 1.5 11.9 3.5 4.5 6 500 4 000

Stand. 5.5 9.8 2.5 6 000 3 500

Notes:(1) The size factor KZ for light framing grades shall be 1.00, except that KZc shall be calculated in accordance withClause 5.5.6.2.2, and KZcp shall be determined in accordance with Clause 5.5.7.5.(2) Tabulated values are based on the following standard conditions:(a) 89 mm width (except for compression properties);(b) dry service conditions; and(c) standard-term duration of load.


August 2001 25

Table 5.3.1CSpecified Strengths and Modulus of Elasticity

for Beam and Stringer Grades (MPa)


Bendingat extremefibre,*

Longi-tudinalshear,

Compression

Tensionparallelto grain,


Parallelto grain,

Perpen-dicularto grain,

fb fv fc fcp ft E E05

D Fir-L SSNo. 1No. 2

19.515.8 9.0

0.913.211.0 7.2

7.010.0 7.0 3.3

12 00012 000 9 500

8 0008 0006 000

Hem-Fir SSNo. 1No. 2

14.511.7 6.7

0.710.8 9.0 5.9

4.6 7.4 5.2 2.4

10 00010 000 8 000

7 0007 0005 500

S-P-F SSNo. 1No. 2

13.611.0 6.3

0.7 9.5 7.9 5.2

5.3 7.0 4.9 2.3

8 500 8 500 6 500

6 0006 0004 500

Northern SSNo. 1No. 2

12.810.8 5.9

0.6 7.2 6.0 3.9

3.5 6.5 4.6 2.2

8 000 8 000 6 000

5 5005 5004 000

*Specified strengths for beams and stringers are based on loads applied to the narrow face. When beams and stringersare subject to loads applied to the wide face, the specified strength for bending at the extreme fibre and the specifiedmodulus of elasticity shall be multiplied by the following factors:

fb E or E05

Select Structural 0.88 1.00No. 1 or No. 2 0.77 0.90

Notes:(1) Beams and stringers have a smaller dimension of at least 114 mm, with a larger dimension more than 51 mmgreater than the smaller dimension.(2) An approximate value for modulus of rigidity may be estimated at 0.065 times the modulus of elasticity.(3) With sawn members thicker than 89 mm that season slowly, care should be exercised to avoid overloading incompression before appreciable seasoning of the outer fibre has taken place; otherwise, compression strengths for wetservice conditions shall be used.(4) Beam and stringer grades listed in this table are not graded for continuity (see Clause 5.5.3).(5) Tabulated values are based on the following standard conditions:(a) 343 mm larger dimension for bending and shear, 292 mm larger dimension for tension and compression parallelto grain;(b) dry service conditions; and(c) standard-term duration of load.


26 August 2001

Table 5.3.1DSpecified Strengths and Modulus of Elasticity

for Post and Timber Grades (MPa)


Bendingatextremefibre,

Longi-tudinalshear,

Compression

Tensionparallelto grain,


Parallelto grain,

Perpen-dicularto grain,

fb fv fc fcp ft E E05

D Fir-L SSNo. 1No. 2

18.313.8 6.0

1.20.90.9

13.812.2 7.5

7.010.7 8.1 3.8

12 00010 500 9 500

8 0006 5006 000

Hem-Fir SSNo. 1No. 2

13.610.2 4.5

1.00.70.7

11.310.0 6.1

4.6 7.9 6.0 2.8

10 000 9 000 8 000

7 0006 0005 500

S-P-F SSNo. 1No. 2

12.7 9.6 4.2

0.90.70.7

9.9 8.7 5.4

5.3 7.4 5.6 2.6

8 500 7 500 6 500

6 0005 0004 500

Northern SSNo. 1No. 2

12.0 9.0 3.9

0.80.60.6

7.5 6.7 4.1

3.5 7.0 5.3 2.5

8 000 7 000 6 000

5 5005 0004 000

Notes:(1) Posts and timbers have a smaller dimension of at least 114 mm, with a larger dimension not more than 51 mmgreater than the smaller dimension.(2) Posts and timbers graded to beam and stringer rules may be assigned beam and stringer strength.(3) An approximate value for modulus of rigidity may be estimated at 0.065 times the modulus of elasticity.(4) With sawn members thicker than 89 mm that season slowly, care should be exercised to avoid overloading incompression before appreciable seasoning of the outer fibre has taken place; otherwise, compression strengths for wetservice conditions shall be used.(5) Tabulated values are based on the following standard conditions:(a) 343 mm larger dimension for bending and shear, 292 mm larger dimension for tension and compression parallelto grain;(b) dry service conditions; and(c) standard-term duration of load.


August 2001 27


Machine Stress-Rated Grades 38 mm Thick by All Widths (MPa)

Grade

Bendingatextremefibre, fb

Modulusofelasticity, E

Tension parallelto grain, ft Compression

89 to 184 mm >184 mm

Parallelto grain, fc

Perpendicularto grain,*fcp

1200Fb-1.2E1350Fb-1.3E1450Fb-1.3E1500Fb-1.4E1650Fb-1.5E1800Fb-1.6E1950Fb-1.7E2100Fb-1.8E2250Fb-1.9E2400Fb-2.0E2550Fb-2.1E2700Fb-2.2E2850Fb-2.3E3000Fb-2.4E

17.419.521.021.723.926.128.230.432.634.736.939.141.343.4

8 300 9 000 9 000 9 70010 30011 00011 70012 40013 10013 80014 50015 20015 90016 500

6.7 8.4 9.010.111.413.215.417.719.621.623.024.125.826.9

——————————————

15.116.917.317.518.118.719.319.920.521.121.722.322.923.5

5.35.35.35.35.35.35.36.56.56.56.56.56.56.5

The following MSR grades provide a modulus of elasticity with higher corresponding strengths. For these MSR grades,qualification and daily quality control for tensile strength are required.

1400Fb-1.2E1600Fb-1.4E1650Fb-1.3E1800Fb-1.5E2000Fb-1.6E2250Fb-1.7E2250Fb-1.8E2400Fb-1.8E

20.323.223.926.129.032.632.634.7

8 300 9 700 9 00010 30011 00011 70012 40012 400

9.010.711.414.614.619.619.621.6

9.010.711.414.614.619.619.621.6

17.117.918.118.719.520.520.521.1

5.35.35.35.35.35.36.56.5

*Compression perpendicular to grain values are for S-P-F MSR (all grades) and Hem-Fir MSR lumber with E grade of10 300 MPa or higher. For other species or grades, use corresponding values for visually stress-graded lumber takenfrom Table 5.3.1A for the appropriate group.Notes:(1) Tabulated values are based on standard-term duration of load and dry service conditions.(2) The size factor Kz for MSR lumber shall be 1.00, except that KZv is given in Table 5.4.5, KZcp is determined inaccordance with Clause 5.5.7.5, and KZc is calculated in accordance with Clause 5.5.6.2.2.


28 August 2001


Evaluated Lumber Grades 38 mm Thick by All Widths (MPa)

Grade

Bending atextremefibre,fb

Modulus ofelasticity,E


Compression

Parallelto grain,fc

Perpendicularto grain,*fcp

M-10M-11M-12M-13M-14M-15M-18M-19M-21M-22M-23M-24M-25M-26

20.322.423.223.226.126.129.029.033.334.034.739.139.840.6

8 30010 30011 000 9 70011 70010 30012 40011 00013 10011 70012 40013 10015 20013 800

9.0 9.5 9.510.711.212.313.514.615.716.821.320.222.420.2

17.117.717.917.918.718.719.519.520.720.921.122.322.522.7

5.35.35.35.35.35.36.55.36.55.36.56.56.56.5

*Compression perpendicular to grain values are for S-P-F MEL (all grades) and Hem-Fir MEL lumber with E grade of10 300 MPa or higher. For other species or grades, use corresponding values for visually stress-graded lumber takenfrom Table 5.3.1A for the appropriate group.Notes:(1) Tabulated values are based on standard-term duration of load and dry service conditions.(2) The size factor Kz for MEL lumber shall be 1.00, except that KZv is given in Table 5.4.5, KZcp is determined inaccordance with Clause 5.5.7.5, and KZc is calculated in accordance with Clause 5.5.6.2.2.


5.4.1 Load Duration Factor, KDThe specified strength of lumber shall be multiplied by a load duration factor, KD, as given inClause 4.3.2.2.

5.4.2 Service Condition Factor, KSThe specified strength of lumber shall be multiplied by a service condition factor, KS, as given inTable 5.4.2.

5.4.3 Treatment Factor, KT

5.4.3.1The specified strength of lumber shall be multiplied by a treatment factor, KT, as given in Table 5.4.3.

5.4.3.2For lumber treated with fire-retardant or other strength-reducing chemicals, strength and stiffnesscapacities shall be based on the documented results of tests that shall take into account the effects oftime, temperature, and moisture content. Test procedures shall meet the requirements of Clause 3.3.2.Note: The effects of fire retardant treatments can vary depending on manufacturing materials and processes. See theCanadian Wood Council’s Commentary for additional explanation.


August 2001 37

5.5.6.6 Spliced Built-up Compressive Members

5.5.6.6.1Spliced nail-laminated built-up columns that are constructed in accordance with Figure 5.5.6.6 may bedesigned for axial loads and bending loads applied parallel to the wide face of the laminations inaccordance with Clauses 5.5.6.6.2 and 5.5.6.6.3, provided that the following additional conditions aremet:(a) the spliced columns shall consist of three members, with nails penetrating all three members;(b) the minimum overall splice length, L, shall be 1200 mm;(c) the spliced columns shall be braced by sheathing, or purlins spaced at a maximum of 600 mm oncentres in the direction perpendicular to the wide face of the laminations;(d) minimum lamination size shall be 38 mm thick by 140 mm wide; and(e) maximum lamination size shall be 38 mm thick by 184 mm wide.

5.5.6.6.2The factored bending resistance shall be determined using Clause 5.5.10 based on equivalent membersof the same size, grade, and species, using(a) 40% of the factored bending resistance of an unspliced built-up beam in the splice region, R; and(b) 100% of the factored bending resistance of an unspliced built-up beam outside of the spliceregion, R.

5.5.6.6.3The factored compressive resistance in the direction parallel to the wide face of the laminations shall bedetermined using Clause 5.5.6.2.2 based on an E05 value equal to 60% of the value for a simplecompression member of the same species and grade.Note: Splicing of built-up members significantly reduces their stiffness and bending resistance, and should be avoidedwherever possible.


38 August 2001

4

6

7

1 1

3

2

5

300 mm

L—2 >–

Legend:1. 3 members, 38 mm thick2. Treated wood portion, when

required (a common application)3. Untreated wood portion4. Splice length, L > 1200 mm5. Splice region, R = 1.5 L6. Nails: 4-in spiral shank; hot-dip

galvanized when used in treated wood; 6 per joint; 300 mm oc; 2 per row driven from alternate sides

7. Butt joints

–

Figure 5.5.6.6Spliced Built-up Columns


August 2001 45

6. Glued-Laminated Timber (Glulam)

6.1 ScopeCharacteristic strengths, design data, and methods specified in Clause 6 apply only to glued-laminatedtimber manufactured in accordance with CSA Standard CAN/CSA-O122.

6.2 Materials

6.2.1 Stress GradesDesign in accordance with Clause 6 is based on the use of the stress grades of glued-laminated timbergiven in Table 6.2.1.Note: The National Building Code of Canada, Part 4, requires that glued-laminated timber be fabricated in plantsconforming to CSA Standard CAN/CSA-O177. A list of certified manufacturers may be obtained from the certifyingagency or agencies providing certification service.

Table 6.2.1Glued-Laminated Timber Stress Grades

Primaryapplication

Wood species

Douglas Fir-LarchSpruce-Lodgepole Pine-Jack Pine

Hem-Fir andDouglas Fir-Larch

Bendingmembers

20f-E, 24f-E20f-EX, 24f-EX

20f-E20f-EX

24f-E24f-EX

Compressionmembers

16c-E 12c-E

Tension members 18t-E 14t-E

6.2.2 Appearance GradesAppearance grades as defined in CSA Standard CAN/CSA-O122 do not affect the specified strength.

6.3 Specified StrengthsThe specified strengths for glued-laminated timber are given in Table 6.3.


46 August 2001

Table 6.3Specified Strengths and Modulus of Elasticity

for Glued-Laminated Timber (MPa)

Douglas Fir-Larch

24f-E 24f-EX 20f-E 20f-EX 18t-E 16c-E

Bending moment (pos.) fb 30.6 30.6 25.6 25.6 24.3 14.0

Bending moment (neg.) fb 14.0 30.6 14.0 25.6 24.3 14.0

Longitudinal shear fv 2.0 2.0 2.0 2.0 2.0 2.0

Compression parallel fc 30.2* 30.2* 30.2* 30.2* 30.2 30.2

Compression parallel combined with bending

fcb 30.2* 30.2 30.2* 30.2 30.2 30.2

Compression perpendicular— compression face bearing— tension face bearing

fcp

7.07.0

7.07.0

7.07.0

7.07.0

7.07.0

7.07.0

Tension net section(See Clause 6.5.11)

ftn 20.4* 20.4 20.4* 20.4 23.0 20.4

Tension gross section ftg 15.3* 15.3 15.3* 15.3 17.9 15.3

Tension perpendicular to grain ftp 0.83 0.83 0.83 0.83 0.83 0.83

Modulus of elasticity E 13 100 13 100 12 400 12 400 13 800 12 400

Spruce- Lodgepole Pine-Jack Pine

Hem-Fir andDouglas Fir-Larch

20f-E 20f-EX 14t-E 12c-E 24f-E 24-EX

Bending moment (pos.) fb 25.6 25.6 24.3 9.8 30.6 30.6

Bending moment (neg.) fb 9.8 25.6 24.3 9.8 10.6 30.6

Longitudinal shear fv 1.75 1.75 1.75 1.75 1.75 1.75

Compression parallel fc 25.2* 25.2* 25.2 25.2 — —

Compression parallelcombined with bending

fcb 25.2* 25.2 25.2 25.2 — —

Compression perpendicular— compression face bearing— tension face bearing

fcp

5.8 5.8

5.8 5.8

5.8 5.8

5.8 5.8

4.6 7.0

7.0 7.0

Tension net section(See Clause 6.5.11)

ftn 17.0* 17.0 17.9 17.0 20.4* 20.4

Tension gross section ftg 12.7* 12.7 13.4 12.7 15.3* 15.3

Tension perpendicular to grain ftp 0.51 0.51 0.51 0.51 0.83 0.83

Modulus of elasticity E 10 300 10 300 10 700 9700 13 100 13 100

*The use of this stress grade for this primary application is not recommended.Notes:(1) Designers are advised to check the availability of grades before specifying.(2) Tabulated values are based on the following standard conditions:(a) dry service conditions; and(b) standard term duration of load.


August 2001 53

R

90º

Lower face Tangent point

d

(a) Pitched Cambered Beam

R

90º

Inner face

Tangent point

d

(b) Arch Member

α

β

β

α

Figure 6.5.6.6.3Double-Tapered Member


6.5.7.1 General

6.5.7.1.1The provisions of Clause 6.5.7 apply to members of rectangular cross-section only.


54 August 2001

Vr

NFv

2A

3KN

KN

1dn

d

2

Vr

NFv0.48AK

NCVZ –0.18 W

f

6.5.7.1.2In the calculation of shear resistance in Clause 6.5.7.2.1, the effect of all loads acting within a distancefrom a support equal to the depth of the member need not be taken into account.

6.5.7.2 Factored Shear Resistance — Case 1

6.5.7.2.1 GeneralThe factored shear resistance, Vr, of glued-laminated beams less than 2.0 m3 in volume, and ofglued-laminated members other than beams, shall be determined in accordance with the provisions ofClause 6.5.7.3, or shall be taken as

whereN = 0.9Fv = fv(KDKHKSvKT)fv = specified strength in shear (Table 6.3), MPaA = cross-sectional area of member, mm2

KN = notch factor (Clause 6.5.7.2.2)Notes:(1) Notches or abrupt changes of section will produce stress concentrations and should be avoided. The magnitude ofthese stress concentrations is reduced by gradual rather than abrupt changes of section.(2) Calculation of factored shear resistance in accordance with these requirements and this formula follows anapproximate method only, and may greatly underestimate the true factored shear resistance of glued-laminatedmembers. For a more detailed and accurate calculation of shear resistance of glued-laminated members, refer to Clause6.5.7.3.

6.5.7.2.2At the location of notches in rectangular members, the specified strength in shear shall be multiplied bya notch factor, KN, determined as follows:(a) for notches at the tension side at supports

(b) for notches at the compression side

(i) for e>d, KN

1dn

d

(ii) for e<d, KN

1dne

d(d dn)

where dn = depth of notch, mm, which must not exceed 0.25de = length of notch, mm, from inner edge of closest support to farthest edge of notch

6.5.7.3 Factored Shear Resistance — Case 2The factored shear resistance, Vr, of glued-laminated beams including those that exceed the maximumvolume restriction of Clause 6.5.7.2.1 shall not be less than the sum of all factored loads, Wf, acting onthe beam and shall be taken as

whereN = 0.9Fv = fv(KDKHKSvKT)


August 2001 55

GaV5

AV5

B4V

5

C

CV

1.825Wf

L

G

0.2

CV

1.825Wf

L

G

0.2

rtotal of concentrated loads

total of uniform loads

fv = specified strength in shear (Table 6.3), MPaA = cross-sectional area of member, mm2

KN = notch factor (Clause 6.5.7.2.2)CV = shear load coefficient (Clause 6.5.7.4)Z = beam volume, m3

6.5.7.4 Shear Load Coefficient, CVFor any load condition not shown in Tables 6.5.7.4A to 6.5.7.4F, the coefficient for simple span,continuous, or cantilevered beams of constant depth may be determined using the following procedure(the principle of superposition of loads does not apply):(a) Construct the shear force diagram for the beam. If the beam is under moving concentrated loads,construct the diagram of the maximum shear forces occurring along the full length of the beam withoutregard to sign convention. (Positive and negative maximum shear forces both show positive.)(b) Divide the total beam length, L, into n segments of variable lengths, Ra, such that within eachsegment there are neither abrupt changes nor sign changes in the shear force.(c) For each segment determine

(i) VA = factored shear force at beginning of segment, N;(ii) VB = factored shear force at end of segment, N; and(iii) VC = factored shear force at centre of segment, N;

and calculate the factor G in accordance with the formula

(d) Determine the coefficient, CV, in accordance with the following formulae:(i) for stationary loads

whereWf = the total of all factored loads applied to the beam, N

(ii) for moving loads

whereWf = the total of all factored moving loads and all factored distributed loads applied to the beam, N

Table 6.5.7.4AShear Load Coefficient, CV, for Simple Span Beams

Number of equal loads equally andsymmetrically spaced

r*

0.0 0.5 2.0 10.0 and over

123456

3.693.693.693.693.693.69

3.343.373.413.453.483.51

2.923.013.123.213.283.34

2.462.672.842.973.083.16


56 August 2001

Table 6.5.7.4BShear Load Coefficient, CV, for Distributed Loads

0.0Type of loading 0.8 1.00.60.4

Pmin/Pmax

0.2

3.40 3.69 3.693.673.633.55

PmaxPmin

L

Table 6.5.7.4CShear Load Coefficient, CV, for Cantilevered Beams

L1/L2Beam type and loading 10.0 and over2.00.5

r*

0.0

0.050.100.200.30

2.732.081.751.62

4.063.072.532.31

5.645.194.363.83

3.914.134.554.88

0.050.100.200.30

4.863.723.172.97

7.135.424.494.10

6.196.726.906.31

4.134.585.506.40


*r =

L = L1 + L2

L2 L1

L = L2 + 2L1

L2 L1L1

Table 6.5.7.4DShear Load Coefficient, CV, for 2-Span Continuous Beams

L1/LLoading case† 10.0 and over2.00.5

r*

0.0

0.20.30.40.5

2.012.152.322.50

2.352.572.823.07

3.043.483.964.42

4.095.106.096.66


*r =

† Values shown correspond to the worst position for the concentrated loads

L1L

P


August 2001 67

Table 7.3C (Concluded)

Nominalthickness,mm

Ratinggrade


Axial stiffness (intension or compression),Ba = EA,N/mm



0E 90E 0E 90E 0E& 90E

9.5 9.5 9.5

11.011.011.0

12.512.512.5

15.515.515.5

18.518.518.5

22.022.022.0

28.528.528.5

ABC

ABC

ABC

ABC

ABC

ABC

ABC

590 000 490 000 390 000

920 000 760 000 610 000

1 300 0001 100 000 900 000

2 600 0002 100 0001 700 000

4 400 0003 600 0002 900 000

7 300 0006 100 0004 900 000

16 000 00013 000 00011 000 000

170 000 170 000 170 000 270 000 270 000 270 000

390 000 390 000 390 000

740 000 740 000 740 000

1 300 0001 300 0001 300 000

2 100 0002 100 0002 100 000

4 600 0004 600 0004 600 000

46 000 39 000 33 000

53 000 46 000 38 000

60 000 52 000 43 000

75 000 64 000 53 000

89 000 77 000 64 000

110 000 91 000 76 000

140 000120 000 98 000

19 00019 00019 000

22 00022 00022 000

25 00025 00025 000

31 00031 00031 000

37 00037 00037 000

44 00044 00044 000

57 00057 00057 000

9 500 9 500 9 500

11 00011 00011 000

12 00012 00012 000

15 00015 00015 000

18 00018 00018 000

22 00022 00022 000

28 00028 00028 000

*For Type 2 Design-Rated OSB panels, tabulated specified capacities are increased by a percentage (See CSAStandard O452.0). For Type 3 Design-Rated OSB panels, specified capacities are proprietary (see Clause 13.3). †Orientation of applied force relative to panel's long direction.Notes:(1) For specified stiffness in bending on edge, use axial stiffness values.(2) Tabulated values are based on dry service conditions and standard-term duration of load.(3) Specified strength in bearing (normal to plane of panel) qp = 4.2 MPa.


68 August 2001

Table 7.3DSpecified Strength, Stiffness, and Rigidity Capacities for

Construction Sheathing OSB

Panelmark (CSAO325)

Minimumnominalthickness,*mm





Planarshear

Bending,vpb,N/mm

Shearin-plane,vpf,

MPa


0E 90E 0E 90E 0E 90E 0E& 90E 0E 90E 0E 90E

2R241R24/2F162R32/2F162R40/2F202R48/2F24

1F161F201F241F321F48

9.511.012.015.018.0

15.015.018.022.028.5

180 240 270 460 630

310 360 480 6401 200

57 68100160240

100150230400720

53 60 65 67 92

60 67 77 92130

18 30 38 48 59

43 48 59 75110

62 71 77 92110

87 92110140280

54 54 67 87100

78 87100130270

4246505560

4754596485

3.8 4.4 4.8 6.1 7.8

5.2 6.1 7.8 9.214.0

2.4 2.4 3.0 3.8 4.4

3.3 3.9 4.5 6.410.0

0.600.600.600.610.65

0.520.610.650.630.73

0.380.330.380.380.37

0.330.390.370.440.55

(Continued)


August 2001 87

9.3.3.2 Shearwall Segment Aspect RatioThe maximum aspect ratio (height-to-length ratio) of a shearwall segment shall be 3.5:1. The height isdefined as the height from the underside of the bottom shearwall plate to the topside of the topshearwall plate within a storey.

9.3.3.3 Shearwalls with OpeningsShearwalls with openings shall be analyzed as the sum of the separate shearwall segments. Thecontribution of sheathing above and below openings shall not be included in the calculation of shearwallresistance.

9.3.3.4 Shearwalls with Dissimilar MaterialsExcept as allowed in Clause 9.3.3.5, shearwalls constructed with dissimilar materials, thicknesses, or nailspacings along the length of the shearwall shall be analyzed as the sum of the separate shearwallsegments.

9.3.3.5 Alternative Method for Shearwalls with Dissimilar MaterialsShearwalls constructed with dissimilar materials, thicknesses, or nail spacings along the length of theshearwall may be analyzed, in accordance with Clause 9.5.1, as a shearwall of uniform construction,provided that the least value of vdKDKSFJubJsp is assumed to apply over the entire shearwall.

9.3.4 Shearwalls with Multiple Layers

9.3.4.1 A Shearwall with Two Layers of Panels on One Side The factored shear resistance for a shearwall with two layers of the same or different panels applied toone side is determined by the first (inside) layer of panels, except as allowed in Note 5 to Table 9.5.1A.

9.3.4.2 Two-Sided ShearwallThe factored shear resistance from each side of the same shearwall is cumulative when panels of thesame or different materials are applied on both sides. Note: See appropriate seismic force modification factor, R, in Clauses 9.5.3 and 9.5.4.

9.3.5 Concrete or Masonry Wall Anchorage

9.3.5.1 Anchorage DesignWhere wood roofs and floors are used to provide lateral support to concrete and masonry walls, theyshall be anchored to these walls. The anchorage shall provide a direct connection between the walls andthe roof or floor construction. The connections shall be capable of resisting the lateral force induced bythe wall, but not less than 3 kN per lineal metre of the wall.

9.3.5.2 Anchorage DetailsAnchorage of concrete or masonry walls shall not be accomplished by use of toe-nails or nails subject towithdrawal, nor shall wood ledgers be designed to resist tensile stresses perpendicular to grain.

9.3.6 Shearwall AnchorageThe anchor bolts to resist lateral forces shall be designed in accordance with Clause 10.


9.4.1 Load Duration Factor, KD The specified shear strengths for wood-based shearwalls and diaphragms shall be multiplied by the loadduration factor, KD, given in Clause 4.3.2.Note: Specified shear strengths for gypsum wallboard shearwalls apply only to short-term load duration, and KD is notapplicable.


88 August 2001

Maximum 2440 mm

Table 9.4.4Strength Adjustment Factor, Jub,

for Horizontally Sheathed Unblocked Shearwalls*

150150

Nail spacing atsupported edges,mm

150300

Nail spacing atintermediate studs,mm

1.00.8

Stud spacing, mm

0.80.6

0.60.5

0.50.4

300 400 500 600

*Specified shear strength of an unblocked shearwall shall be calculated by multiplying the strength adjustment factor by the specified shear strength of a blocked shearwall with 600 mm stud spacing, and with nails spaced at 150 mm on centre around panel edges and 300 mm on centre along intermediate framing members.Note: Strength adjustment factor shall only be applicable to structural wood-based panels.

Horizontal panels,no blocking

9.4.2 Service Condition Factor, KSFThe specified shear strengths for wood-based shearwalls and diaphragms shall be multiplied by theservice condition factor, KSF, given in Table 10.2.1.5 for lateral loads on nails.

9.4.3 Species Factor for Framing Material, JspThe specified shear strengths for wood-based shearwalls and diaphragms shall be multiplied by thespecies factor for framing material, Jsp, as given in Table 9.4.3.

Table 9.4.3Species Factor for Framing Material, Jsp

Jsp Visually graded lumber Glued-laminated timberMSR (or MEL) E-Grade of S-P-F,* MPa

1.00.90.80.7

Douglas Fir-LarchHem-FirS-P-FNorthern Species

Douglas Fir-LarchN/ASpruce-PineN/A

13 800 to 16 50012 400 to 13 100 8300 to 11 700 N/A

*For other species of MSR or MEL lumber, use visually graded lumber values.

9.4.4 Strength Adjustment Factor for Unblocked Shearwalls, JubThe specified shear strengths for horizontally sheathed unblocked shearwalls sheathed with wood-basedpanels shall be multiplied by the strength adjustment factor Jub, as given in Table 9.4.4.


August 2001 91

L1 L3 L2

H

H

h2

h1

q2 F2

F1q1

qw2qw2

qw1qw1

qw2qw2

qw1qw1

q1q1

q2q2

P21

Ptop21

R22

P22

R21

F22F21

Ptop22

Ptop11

F12F11

Ptop12

P11R12 = F12 – P12P12

R11 R12

H + h1

L2


2

Ptop12 = q1 –R22L2

2

R11 = F11 – P11H + h1

L1


2

Ptop11 = q1 –R21+ q1L1

2L3

2

R22 = F22 – P22H + h2

L2


2

Ptop22 = q2L2

2

R21 = F21 – P21H + h2

L1


2

Ptop21 = q2 + q2L1

2L3

2

Figure 9.4.5.2Multi-Storey Shearwall Force Diagrams


92 August 2001

9.5.2 Shear Resistance of Nailed Diaphragms The factored shear resistance of nailed diaphragms of structural wood-based panels or diagonal lumbersheathing constructed in accordance with Clauses 9.5.3 and 9.5.5, respectively, shall be determined asfollows:

Vr = N vdKDKSF JspLD

whereN = 0.7vd = specified shear strength for diaphragms with plywood, OSB, or waferboard (Table 9.5.2) or

diagonal lumber sheathing (Clause 9.5.5), kN/mJsp = species factor for framing material (Clause 9.4.3)LD = dimension of diaphragm parallel to direction of factored load, m

9.5.3 Nailed Shearwalls and Diaphragms Using Plywood, OSB, orWaferboard

9.5.3.1 GeneralShearwalls and diaphragms sheathed with plywood, OSB, or waferboard may be used to resist shear dueto lateral forces based on the specified shear strength given in Table 9.5.1A for shearwalls and Table9.5.2 for diaphragms.Notes:(1) Seismic force modification factor, R, is equal to 3 when nailed plywood, OSB, or waferboard shearwalls areconsidered to resist lateral loads.(2) Table 9.5.3 provides an equivalence between tabulated thickness and panel marks.

9.5.3.2 Framing MembersFraming members shall be at least 38 mm wide and be spaced no greater than 600 mm apart inshearwalls and diaphragms. In general, adjoining panel edges shall bear and be attached to the framingmembers, and a gap of not less than 2 mm shall be left between wood-based panel sheets.

9.5.3.3 Framing and PanelsShearwalls and diaphragms using plywood, OSB, or waferboard shall be constructed with panels not lessthan 1200 × 2400 mm, except near boundaries and changes in framing, where up to two short ornarrow panels may be used. Panels for diaphragms shall be arranged as indicated in Table 9.5.2. Framing members shall be provided at the edge of all panels in shearwalls except horizontally sheathedunblocked shearwalls where blocking at the middle of the wall height is omitted. Shearwalls and diaphragms shall be designed to resist shear stresses only, and perimeter members shallbe provided to resist axial forces resulting from the application of lateral design forces. Perimetermembers shall be adequately interconnected at corner intersections, and member joints shall be splicedadequately. Panels less than 300 mm wide shall be blocked.

9.5.3.4 NailingThe nails and spacing of nails at shearwall and diaphragm boundaries and the edges of each panel shallbe as shown in Table 9.5.1A for shearwalls and in Table 9.5.2 for diaphragms. Nails shall be placed not less than 9 mm from the panel edge and shall be placed along all intermediateframing members at 300 mm on centre for floors, roofs, and shearwalls. Nails shall be firmly driven intoframing members but shall not be over-driven into sheathing. For structural wood-based sheathing,nails shall not be over-driven more than 15% of the panel thickness.

9.5.4 Nailed Shearwalls Using Gypsum WallboardShearwalls using gypsum wallboard shall be constructed with panels not less than 1200 × 2400 mm,except near boundaries and changes in framing, where up to two short or narrow panels may be used.


August 2001 93

Shearwalls sheathed with gypsum wallboard may be used to resist shear due to lateral forces based onthe specified shear strength given in Table 9.5.1B for shearwalls. Gypsum wallboard application nails or screws shall be placed not less than 9 mm from the panel edge. Gypsum wallboard shall be used in combination with structural wood-based panels. The factored shearresistance of gypsum wallboard shall be equal to or less than the percentage of storey shear forces inTable 9.5.4. The application of gypsum wallboard shall be restricted to platform frame constructionwhere the height of a storey does not exceed 3.6 m.Notes:(1) Seismic force modification factor, R, is equal to 2 when gypsum wallboard is considered to resist lateral loads.(2) There should exist a balanced spatial distribution of the gypsum wallboard and wood-based panels resisting shearin a given direction in a particular storey.

9.5.5 Nailed Shearwalls and Diaphragms Using Diagonal LumberSheathing

9.5.5.1 GeneralNailed shearwalls and diaphragms as described in Clauses 9.5.5.2 to 9.5.5.4 may be used to resist lateralforces. The specified shear strength, vd, with a single layer of diagonally sheathed lumber (Clause9.5.5.2) shall be taken as 8 kN/m; that for a double layer of diagonally sheathed lumber (Clause 9.5.5.3)as 24 kN/m.

9.5.5.2 Single-Layer Diagonal SheathingSingle-layer diagonal sheathing shall be made up of 19 mm boards laid at an angle of approximately 45°to supports. Boards shall be nailed to each intermediate member with not less than two common nails(d = 3.25 mm) for 19 × 140 mm boards and three common nails (d = 3.25 mm) for 19 × 184 mm orwider boards. One additional nail shall be used in each board at shear panel boundaries. End joints in adjacent rows of boards shall be staggered by at least one stud or joist space, and joints onthe same support shall be separated by at least two rows of boards. Shearwalls and diaphragms made up of 38 mm thick diagonal sheathing using common nails(d = 4.06 mm) may be used at the same shear values and in the same locations as for 19 mm boards,provided that there are no splices in adjacent boards on the same support and the supports are not lessthan 89 mm in depth or 64 mm in thickness.

9.5.5.3 Double-Layer Diagonal SheathingDouble-layer diagonal sheathing shall conform to Clause 9.5.5.2 and shall consist of two layers ofdiagonal boards at 90° to each other on the same face of the supporting members.

9.5.5.4 Boundary MembersDiagonal sheathing produces a load component acting normal to the boundary members in the plane ofthe shear panel. Boundary members in diagonally sheathed shearwalls and diaphragms shall bedesigned to resist the bending stresses caused by the normal load component.

9.5.6 Moment Resistance of Nailed Shearwalls and Diaphragms

9.5.6.1 GeneralExcept as provided in Clause 9.5.6.2, the factored moment resistance of nailed shearwalls anddiaphragms shall be determined as

Mr = Prh

wherePr = factored axial tension and compression resistance of the elements resisting chord forces with due

allowance being made for joints, N


94 August 2001

h = centre-to-centre distance between moment resisting elements, mm= centre-to-centre distance between diaphragm chords in the design of diaphragms, mm= centre-to-centre distance between stud chords in shearwall segments designed with hold-down

connections at both ends of the shearwall segment, mm= length of shearwall segment minus 300 mm for shearwall segments designed without hold-down

connections at both ends of the segment, mm

9.5.6.2 Moment Resistance for Shearwall Segments without Hold-downsFor shearwall segments without hold-downs, moment resistance calculation specifically for design of thetension chords shall not be required.

9.6 Detailing Requirements

9.6.1 GeneralAll boundary members, chords, and struts of nailed shearwalls and diaphragms shall be designed anddetailed to transmit the induced axial forces. The boundary members shall be fastened together at allcorners.

9.6.2 Fastenings to Shearwalls and Diaphragms Fastenings and anchorages capable of resisting the prescribed forces shall be provided between theshearwall or diaphragm and the attached components.


August 2001 99

Table 9.5.3Panel Marking Equivalence in Shearwall and Diaphragm Tables

In shearwall Table 9.5.1A In diaphragm Table 9.5.2

Minimum nominalthickness, mm Minimum panel mark

Minimum nominalthickness, mm Minimum panel mark

7.5 9.511.012.515.5

2R202R241R24/2F162R32/2F16 or 1F162R40/2F20

7.5 9.511.012.515.518.5

2R202R241R24/2F162R32/2F162R40/2F20 or 1F202R48/2F24 or 1F24

Notes:(1) For OSB panels rated to CSA Standard CAN/CSA-O325.0, the minimum nominal thickness may be 0.5 mm lessthan the thickness shown above. No adjustment to the tabulated shear strength values is required.(2) For alternative panel marks meeting the minimum requirements, see Clause A7.2.2.2.

Table 9.5.4Maximum Percentage of Total Shear ForcesResisted by Gypsum Wallboard in a Storey

Storey

Percentage of shear forces

4-storey building 3-storey building 2-storey building 1-storey building

4th 80 — — —

3rd 60 80 — —

2nd 40 60 80 —

1st 40 40 60 80

Notes:(1) A force modification factor of R = 2.0 is used when gypsum wallboard sheathing is considered to resist lateral loads.(2) Maximum storey height shall not exceed 3.6 m.

10. Fastenings

10.1 ScopeClause 10 provides criteria for the engineering design and appraisal of connections using split ring andshear plate connectors, bolts, drift pins, lag screws, timber rivets (also known as glulam rivets), trussplates, nails, spikes, and joist hangers.Note: Lateral resistance values for bolts, drift pins, and lag screws are based on relative density of the wood material. Reference density values are given in Table A10.1.

10.2 General Requirements

10.2.1 All FasteningsNote: Joint details should be avoided where shrinkage of the wood can lead to excessive tension perpendicular to grain.

10.2.1.1The tables are predicated on the requirement that the projecting end of a member shall not be trimmedor otherwise altered in such a manner as to reduce the specified minimum end distance.


100 August 2001

d

Fastening(s)

de

de

10.2.1.2Under severe conditions conducive to corrosion, connection design should provide adequate protection.

10.2.1.3Joints made using hard maple, soft maple, elm, beech, black oak, white oak, or birch may be assignedthe same resistances as the D Fir-L species group.

10.2.1.4Where a fastening or group of fastenings exerts a shear force on a member, the factored shear resistanceof the member as calculated in Clauses 5.5.5 and 6.5.7 shall be based upon the dimension de shown inFigure 10.2.1.4, instead of the dimension d. Dimension de is defined as the distance, measuredperpendicular to the axis of the member, from the extremity of the fastening or group of fastenings tothe loaded edge of the member.

Figure 10.2.1.4Shear Depth

10.2.1.5 Service Condition Factor, KSF The service condition factor, KSF, for fastenings is given in Table 10.2.1.5.

10.2.1.6 Load Duration Factor, KDThe load duration factor, KD, for fastenings is given in Table 4.3.2.2.

10.2.1.7 Treatment Factor, KTFor connections containing wood-based members treated with fire-retardant or other strength-reducingchemicals, strength capacities of connections shall be based on the documented results of tests that shalltake into account the effect of time, temperature, and moisture content. Test procedures shall meet therequirements of Clause 3.3.2.Note: The effects of fire-retardant treatments can vary depending on manufacturing materials and processes. See theCanadian Wood Council’s Commentary for additional explanation.

10.2.1.8Joints shall be assembled so that the surfaces are brought into close contact.


August 2001 159

12.5.2.5 Constant Nonrectangular Cross-SectionFor nonrectangular compression members of constant section, r shall be substituted for member12

width or depth in Clause 5.5.6, where r is the applicable radius of gyration of the cross-section of themember.

12.5.2.6 Variable Circular Cross-SectionThe radius of gyration of round tapered compression members shall be calculated for an effectivediameter equal to the minimum diameter plus 0.45 times the difference between the maximum andminimum diameters. The factored compressive resistance determined in this manner shall not exceedthe factored resistance based on the minimum diameter in conjunction with a slenderness factorKC = 1.00.

12.5.3 Poles as Bending MembersThe factored bending moment resistance, Mr, of round members shall be taken as that of a squaremember having the same cross-sectional area. A tapered round member shall be considered as anequivalent square member of variable cross-section.

13. Proprietary Structural Wood Products

13.1 ScopeClauses 13.2 to 13.4 provide design methods for proprietary structural wood products that conform tothe applicable referenced standards and the additional requirements contained in Clause 13.Note: Clauses 13.2 to 13.4 are provided as a reference for designers to explain the origin of manufacturers’ proprietarydesign values. In general, proprietary design values are published by the product manufacturer (i.e., proprietary designliterature and/or CCMC Evaluation Reports within the CCMC Registry of Product Evaluations) with appropriate factorsfor specific applications. The designer is not normally expected to calculate the proprietary product properties using theequations provided herein. For applications where adjustments to design values may be warranted, the designer isrecommended to seek guidance from the product manufacturer. For additional information on proprietary structuralwood products in general, and prefabricated wood I-joists and structural composite lumber products in particular, see theCanadian Wood Council’s Commentary.

13.2 Prefabricated Wood I-Joists

13.2.1 GeneralExcept as specified in Clause 13.2.2.2, all prefabricated wood 3-joists for use under the provisions of thisStandard shall meet the requirements of, and be evaluated for strength and stiffness in accordance with,ASTM Standard D 5055. Determination of characteristic values for design with prefabricated woodI-joists shall be in accordance with Clause 13.2.3.6. All prefabricated wood I-joists for use under the provisions of Clause 13.2 shall bear the mark of acertification organization (C.O.) indicating certification by the C.O. as meeting the applicablerequirements of Clause 13.2.

13.2.2 Materials

13.2.2.1 Flange MaterialsThe provisions of Clause 13.2 apply to flanges as specified in Clause 5 for sawn structurally gradedlumber or Clause 6 for glued-laminated timber. Lumber not conforming to Clause 5 and structuralcomposite lumber products may be used as flange material when such material is qualified by testing asspecified in ASTM Standard D 5055.

13.2.2.2 Structural Panel WebsWebs for prefabricated wood I-joists shall be manufactured from structural panels conforming to CSA


160 August 2001

Standard O121, O151, O153 (Exterior Bond), CAN/CSA-O325.0, O437.0, or O452.0. Note: For additional information, see the Canadian Wood Council’s Commentary.

13.2.2.3 AdhesivesPrefabricated wood I-joists shall be manufactured using(a) adhesives conforming to CSA Standard O112.6 or O112.7; or (b) an adhesive demonstrated to provide equivalent performance to the adhesives referenced inItem (a).Note: For additional information on equivalent adhesive systems, see the Canadian Wood Council’s Commentary.


13.2.3.1 Specified Strength Parallel to Grain, faThe specified strength parallel to grain, fa, shall be the lesser of the specified strength in tension parallelto grain, ft, or the specified strength in compression parallel to grain, fc, as defined in Clauses 13.2.3.2and 13.2.3.3.

13.2.3.2 Specified Strength in Tension Parallel to Grain, ftThe specified strength in tension parallel to grain, ft, shall be determined in one of the following ways:(a) where the flange material is sawn lumber conforming to Clause 5.2 or glued-laminated timberconforming to Clause 6.2 of this Standard, the specified strength in tension parallel to grain shall bedetermined from ft in Clause 5.3, or ftg in Clause 6.3, respectively; and(b) where the flange material is not as described in Item (a), ft shall be taken as

ft = t Kr

wheret = the characteristic value for tension parallel to grain as defined in Clause 13.2.3.6, MPaKr = reliability normalization factor for bending and tension from Table 13.2.3.2


August 2001 163

13.2.4.4 System Factor, KHBDepending upon the type of flange material, prefabricated wood I-joists used in a load sharing systemshall be permitted the following moment resistance adjustment increases:

Prefabricated wood I-joist flange KHB

Visually graded sawn lumber 1.10Machine stress-rated and machine evaluated lumber 1.07Structural composite lumber products 1.04

To qualify for the above increase, the prefabricated wood I-joist shall be part of a wood-framing systemconsisting of at least three parallel prefabricated wood I-joists joined by transverse load distributingelements adequate to support the design load and shall be spaced not more than 610 mm on centre.


13.2.5.1 Bending Moment ResistanceThe factored bending moment resistance, Mr, of prefabricated wood I-joists shall be calculated usingeither

Mr = N FtSKL

or

Mr = N Mcv (KDKSKHBKT) KrKL

whereN = 0.90Ft = fa(KDKSKHBKTKZt)fa = specified strength parallel to grain, per Clause 13.2.3.1, MPaS = net section modulus, all web materials removed and, when appropriate, calculated as a

transformed section, mm3

KL = lateral stability factor, per Clause 13.2.5.2KHB = system factor, per Clause 13.2.4.4KZt = the size factor for tension parallel to grain, from Table 5.4.5, applicable only to visually

stress-graded lumber used in accordance with Clause 13.2.3.1Mcv = the characteristic value for moment capacity as defined in Clause 13.2.3.6(d), NCmKr = reliability normalization factor for bending and tension, from Table 13.2.3.2

13.2.5.2 Lateral Stability Factor, KLThe lateral stability factor, KL, shall be taken as unity when lateral support is provided at points ofbearing, to prevent lateral displacement and rotation, and along all compression edges. Lateral supportrequirements and lateral stability factors for other applications such as continuous spans shall be basedon analytical and engineering principles or documented test data, or both, that demonstrate the safe useof the product in the intended application.Note: For additional information on lateral stability, see the Canadian Wood Council’s Commentary.

13.2.5.3 NotchesNotching or cutting of the flanges of prefabricated wood I-joists shall not be permitted, unless suchdetails have been evaluated and are demonstrated to be acceptable based on documented test data.

13.2.5.4 Shear ResistanceThe factored shear resistance, Vr, of prefabricated wood I-joists shall be taken as

Vr = NVc Kv


164 August 2001

Elw

Ba

WD

3

12KSEKTE

whereN = 0.90Vc = specified shear capacity for a given brand and depth of prefabricated wood I-joist, in accordance

with Clause 13.2.3.4, NKv = KDKSKT

Neglecting loads within a distance from the support equal to the depth of the member shall not bepermitted, and any adjustments to the shear design value near the support shall be substantiated byindependent testing to the shear capacity criteria in ASTM Standard D 5055.

13.2.5.5 Web Openings, Bearing Length, and Web StiffenerRequirementsDesigners shall obtain information regarding web openings, bearing length, and web stiffenerrequirements from specific prefabricated wood I-joist manufacturers. The requirements for permittedweb openings, minimum bearing length, and web stiffener details shall be determined in accordancewith ASTM Standard D 5055.Note: For additional information, see the Canadian Wood Council’s Commentary.

13.2.5.6 Serviceability Limit StatesDesign of prefabricated wood I-joists for serviceability limit states shall be in accordance withClauses 4.1.3 and 4.5. Deflection calculations shall include shear deformation. The flange moduli of elasticity for stiffness calculations shall be taken as

Es = E (KSE KTE)

The effective stiffness, EIW, of prefabricated wood I-joist web members employing structural panels inClause 7.3 conforming to CSA Standard O121, O151, CAN/CSA-O325.0, or O452.0 shall be taken as

The shear-through-thickness rigidity, WS, of structural panels in Clause 7.3 used as web members ofprefabricated wood I-joists and conforming to CSA Standard O121, O151, CAN/CSA-O325.0, or O452.0shall be taken as

WS = Bv KSG KTG

whereE = specified modulus of elasticity, per Clause 13.2.3.5KSE = service condition factor for modulus of elasticity

= 1.0 for dry service condition (in accordance with Clause 13.2.4.2)KTE = treatment factor for modulus of elasticity

= 1.0 for untreated prefabricated wood I-joists (see Clause 13.2.4.3)Ba

= axial stiffness (tension or compression) from Table 7.3A, 7.3B, 7.3C, or 7.3D, N/mmWD = overall depth of the structural panel web, mmBv = shear-through-thickness rigidity from Table 7.3A, 7.3B, 7.3C, or 7.3D, N/mmKSG = service condition factor for shear-through-thickness rigidity

= 1.0 for dry service condition (see Clause 13.2.4.2)KTG = treatment factor for shear-through-thickness rigidity

= 1.0 for untreated prefabricated wood I-joists (see Clause 13.2.4.3)Note: Axial web stiffness and web shear-through-thickness rigidity for products not covered by Tables 7.3A, 7.3B, 7.3C,or 7.3D must be determined from appropriate standards or documented test data, which can be obtained from theprefabricated wood I-joist manufacturer.


August 2001 165

13.2.6 Fastenings

13.2.6.1 NailsNailed connections shall be designed in accordance with Clause 10.9.

13.2.6.2 Joist Hangers and Other Framing ConnectorsThe use of joist hangers and other framing connectors with prefabricated wood I-joists shall be based ondocumented test data.Note: Required details of use and attachment are available from the manufacturers. For additional information, seeClause 10.10 and the Canadian Wood Council’s Commentary.

13.3 Type 3 (Proprietary) Design-Rated OSB Panels

13.3.1 ManufactureType 3 (Proprietary) design-rated OSB structural panels shall be manufactured and their structuralproperties evaluated in accordance with the testing, quality control, and quality assurance andcertification provisions of the CSA Standard O452 Series. Type 3 OSB structural panels may be of anythickness.

13.3.2 Panel Identification and Certificates of ConformanceEach Type 3 (Proprietary) OSB product shall be identified by a distinctive company product designationapproved by the certification organization. Its compliance with the requirements in CSA StandardO452.0 for Type 3 products shall be verified by the Certificate of Conformance issued by the certificationorganization. The Certificate of Conformance shall identify the product designation, the nominalthickness, and the assigned specified capacities (see Clause 13.3.4).

13.3.3 Basic Structural CapacitiesNominal thicknesses and basic structural capacities from which specified design capacities are derivedshall be determined in accordance with the CSA Standard O452 Series.Note: The basic structural capacities are the lower tolerance limits of the mean stiffness and of the lower fifth percentileof strength, determined from testing of the mechanical properties, and adjusted to dry service conditions.

13.3.4 Specified Capacities

13.3.4.1 DerivationThe specified capacities for stiffness and strength of Type 3 OSB structural panels shall be derived foreach product from its basic structural capacities in accordance with Clauses 13.3.4.2 and 13.3.4.3.

13.3.4.2 Specified Stiffness and RigidityThe specified capacities for stiffness and rigidity for a Type 3 OSB panel shall be its basic structuralcapacities, rounded to two significant figures.

13.3.4.3 Specified StrengthsThe standard term specified strength capacities for a Type 3 OSB panel shall be equal to the basicstrength capacities determined in accordance with the CSA Standard O452 Series multiplied by anadjustment factor of 0.8, and rounded to two significant figures.

13.3.4.4 Application of Specified CapacitiesThe specified capacities determined by Clauses 13.3.4.1 to 13.3.4.3 for a Type 3 OSB structural panelmay be used in design procedures for structural panels specified in this Standard.


166 August 2001

13.3.5 Design MethodsDesigns with Type 3 (Proprietary) design-rated OSB shall be in accordance with the modification factorsand design methods for OSB structural panels (see Clauses 7.4 and 7.5).

13.4 Structural Composite Lumber Products

13.4.1 GeneralAll structural composite lumber products for use under the provisions of this Standard shall bemanufactured to, and evaluated for characteristic values in accordance with, the requirements ofASTM Standard D 5456. All structural composite lumber products for use under the provisions of Clause 13.4, includingproducts subjected to secondary processing operations, shall bear the mark of a certification organization(C.O.) indicating certification by the C.O. as meeting the applicable requirements of Clauses 13.4.2 to13.4.6.

13.4.2 AdhesivesStructural composite lumber products shall be manufactured using(a) adhesives conforming to CSA Standard O112.6 or O112.7; or (b) an adhesive demonstrated to provide equivalent performance to the adhesives referenced inItem (a).Note: For additional information on equivalent adhesives, see the Canadian Wood Council’s Commentary.


13.4.3.1 GeneralSpecified strengths and moduli of elasticity for structural composite lumber products for use with thisStandard shall be established in accordance with Clauses 13.4.3.2 to 13.4.3.7.

13.4.3.2 Specified Bending Strength, fbThe specified bending strength, fb, for structural composite lumber products shall be taken as

fb = FBKr

whereFB = the characteristic value in bending as determined by ASTM Standard D 5456, MPaKr = reliability normalization factor for bending and tension from Table 13.2.3.2

13.4.3.3 Specified Shear Strength, fvThe specified shear strength, fv, for structural composite lumber products shall be taken as

fv = vSCLKr

wherevSCL = the characteristic value in shear as determined by ASTM Standard D 5456, MPaKr = reliability normalization factor for shear for structural composite lumber from Table 13.2.3.2

13.4.3.4 Specified Compression Strength Parallel to Grain, fcThe specified compression strength parallel to grain, fc, for structural composite lumber products shall betaken as

fc = c Kr

wherec = the characteristic value in compression parallel to grain as determined by ASTM Standard D 5456,

MPa


August 2001 167

Kr = reliability normalization factor for compression parallel to grain from Table 13.2.3.2

13.4.3.5 Specified Compression Strength, Perpendicular to Grain, fcpThe specified compression strength perpendicular to grain, fcp (MPa), for structural composite lumberproducts shall not exceed the characteristic value for compression perpendicular to grain as determinedby ASTM Standard D 5456, multiplied by 1.09.

13.4.3.6 Specified Tension Strength Parallel to Grain, ftThe specified tension strength parallel to grain, ft, for structural composite lumber products shall betaken as

ft = tSCLKr

wheretSCL = the characteristic value in tension parallel to grain as determined by ASTM Standard D 5456, MPaKr = reliability normalization factor for bending and tension from Table 13.2.3.2

13.4.3.7 Specified Modulus of ElasticityThe specified moduli of elasticity, E, for structural composite lumber products shall be the mean modulias determined by ASTM Standard D 5456.


13.4.4.1 Load Duration Factor, KDThe load duration factors, KD, as given in Clause 4.3.2 are applicable to the specified strengths ofstructural composite lumber products, provided that appropriate testing has been conducted thatdemonstrates the validity of those load duration factors for use with the structural composite lumberproduct.Note: See also the Canadian Wood Council’s Commentary.

13.4.4.2 Service Condition Factor, KSThe specified strengths and stiffness of structural composite lumber products described in Clause 13.4.4are applicable for use in dry service conditions with KS = 1.0. If structural composite lumber products areto be used in other than dry service conditions, the specified strengths and stiffness shall be evaluated,including development of appropriate strength reduction factors, based on documented test results.

13.4.4.3 Treatment Factor, KTThe specified strengths and stiffness described in Clause 13.4.4 are applicable to untreated structuralcomposite lumber products with KT = 1.0. Treatment adjustments for specified strengths and stiffnessshall be based on the documented results of tests that shall take into account the effects of time,temperature, and moisture content.

13.4.4.4 System Factor, KH The system factor, KH, permitted for structural composite lumber products used in a load-sharing systemshall be 1.04. To qualify for the above increase, the structural composite lumber products shall be part of a wood-framing system consisting of at least three parallel members joined by transverse load distributingelements adequate to support the design load and shall not be spaced more than 610 mm on centre.

13.4.4.5 Size Factor in Bending, KZbThe size factor in bending, KZb, for structural composite lumber products shall be taken as

KZb = d1

d

1

mL1

L

1

m


168 August 2001

Vr

N Fv

2A

3KZv

whered1, L1 = depth and length of unit volume membersd, L = depth and length of an application memberm = parameter determined in accordance with Annex A1 of ASTM Standard D 5456. Note: For further information regarding depth and length of unit volume members, see ASTM Standard D 5456.

13.4.4.6 Size Factor in Tension, KZtThe size factor in tension, KZt, for structural composite lumber products shall be taken as

KZt = L1

L

1

m

whereL1 = base length between test grips, as tested in Section 5.5.2 of ASTM Standard D 5456L = end use lengthm = parameter determined in accordance with Annex A1 of ASTM Standard D 5456.


13.4.5.1 Bending Moment ResistanceThe factored bending moment resistance, Mr, of structural composite lumber products shall be taken as

Mr = NFb SKZb KL

whereN = 0.90Fb = fb (KD KH KSb KT)fb = specified bending strength, per Clause 13.4.3.2, MPaKZb = size factor in bending, per Clause 13.4.4.5KL = lateral stability factor, per Clause 13.4.5.2

13.4.5.2 Lateral Stability Factor, KLThe lateral stability factor, KL, for structural composite lumber products shall be determined inaccordance with Clause 5.5.4.2.

13.4.5.3 NotchesThe use of structural composite lumber products with notches or cuts shall not be permitted unless suchdetails have been evaluated and are demonstrated to be acceptable based on documented test data.

13.4.5.4 Shear ResistanceThe factored shear resistance, Vr, of structural composite lumber products shall be taken as

whereN = 0.90Fv = fv (KD KSv KT)fv = specified shear strength of structural composite lumber products, per Clause 13.4.3.3, MPaA = cross-sectional area of member, mm2

KZv = 1.0

Note: For additional information on size factor in shear, KZv, see the Canadian Wood Council’s Commentary.


August 2001 179

MfPf∆

Mr

Pf

Pr

2

<1.0

Mfx

wfH 2

6L(H 3a)

L x

HL

H Ax

H

3

A5.5.12 Preserved Wood Foundations

A5.5.12.1Studs for preserved wood foundations may be designed in accordance with recognized engineeringmethods. When assumed to be laterally supported, and when no surcharge exists, the formulaepresented in Clauses A5.5.12.6 to A5.5.12.12 give conservative approximations of sufficient accuracy forpractical construction. Dimensions used in the formulae are identified in Figure A5.5.12.1.

A5.5.12.2Studs for exterior foundation walls may be designed as members subjected to combined bending andaxial compressive loading. Deflection due to lateral and axial loads should not exceed 1/300 of theunsupported height of the stud.

A5.5.12.3Sheathing for exterior foundation walls may be designed as simple bending members. The calculatedmaximum deflection at a point 300 mm above the bottom of the sheathing should not exceed 1/180 ofthe span of sheathing between studs. The nominal thickness of sheathing should not be less than12.5 mm.

A5.5.12.4Floors and connections between floors and walls shall be designed to withstand loads imposed uponthem by lateral soil pressure as well as floor loads appropriate for the occupancy.

A5.5.12.5Unequal pressure distribution may result from differing backfill heights on opposite sides of a building,openings in foundation walls, openings in floors at the top of foundation walls, or other causes. Framingmembers and sheathing shall be designed to resist loads resulting from unequal pressure distribution, bydiaphragm action, or by other suitable means.

A5.5.12.6Combined bending and axial load effects may be evaluated using the formula

whereMf = maximum factored moment due to lateral load on stud, NCmmPf = factored axial load on stud, N) = deflection due to lateral load at point where Mf is calculated, mmMr = factored bending moment resistance, in accordance with Clause 5.5.4.1, NCmmPr = factored compressive resistance, in accordance with Clause 5.5.6.2.2, N

Notes:(1) A KD factor of 0.65 applies to the calculation of Mr and a KD factor of 1.0 applies to the calculation of Pr.(2) The value of Pf ) represents secondary bending, which may be negligible.

A5.5.12.7The value of Mf in Clause A5.5.12.6 is the maximum moment due to factored lateral load, and may becalculated using the following expression derived from recognized engineering formulae. At any point,x, above the floor the factored bending moment, Mfx (NCmm), is


180 August 2001

Mf

wfH 2

6LL H

2

3

H 3

3L

x HH 3

3L

Mf

wfH 2

6LKm

Km(H 3a) K

1

L a H

HLK

3

1

K1

H 3a

3L

x H a HH 3a

3L

K1

H a

Hand x 0

∆wf(L x)

360EILHK∆

wherewf = maximum factored lateral load per stud, N/mm

= maximum factored lateral soil pressure, N/mm2, times stud spacing, mmH, L, a, x = variables shown in Figure A5.5.12.1, mm

A5.5.12.8The following formulae may be used to determine the maximum factored moment, Mf, and its location,x:(a) for wood sleeper and slab floors

and

(b) for suspended floors, both the moment between supports and the cantilever moment at the supportshould be checked using

where

and between supports

at the support

Note: Values of Km for a range of backfill heights and typical wall dimensions are given in Table A5.5.12.8.

A5.5.12.9Secondary moment is the term Pf) in Clause A5.5.12.6. The value of ) may be calculated at any point,x, above the basement floor (see Figure A5.5.12.1), using the formula


August 2001 191

β1

1

1300LpSp(nc1) [1 500exp

0.52(SQ 12.5)]

β20.5×10 16L

p[(n

c1)S

p]3 [(n

R1)S

Q]4.5exp

a 50

100

β3

3µ 1

2Lp

1 µ

50

51 exp

1.9 0.95b

Lp

5

µ 43.9[(nc1)S

p] 0.4 [(n

R1)S

Q] 0.2

qw

23.3Xtpftp[(n

R1)S

p]0.8

Ktpβtp103[(n

c1)S

Q]0.2

Ct

1

βD

ep

(nc1)S

Q

0.2

a = end distance (Figure 10.7.1.7), mmLp = rivet penetration (Figure 10.7.1.1)Kv = constant depending on nR and nC (Table A10.7.2.3D)$v = constant depending on Sp and SQ (Table A10.7.2.3E)( = 90.5 + 5.4 Lp

Note: For cases where b # 175 mm, Sp = 40 mm, SQ = 25 mm, and Lp $ 55 mm, Pv will be greater than Pt

A10.7.2.3.2 Perpendicular-to-Grain LoadingIn Clause 10.7.2.5, the lateral strength resistance for wood capacity perpendicular to grain, qw, may bedetermined from

whereXtp = adjustment factor for tension perpendicular = 1.45ftp = specified strength in tension perpendicular to grain, MPa (Table 6.3)Ktp = constant depending on nR and nC (Table A10.7.2.3F)$tp = constant depending on Sp and SQ (Table A10.7.2.3G)

and the value of the factor, Ct, may be determined from

where$D = constant depending on ep/(nC–1)SQ (Table A10.7.2.3H)ep = unloaded edge distance, mm (Figure 10.7.1.7)

))

)


192 August 2001

Table A10.7.2.3AValues of Kt

Rivetsperrow, nC

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

2 4 6 8101214161820222426

0.750.510.380.300.260.230.210.200.180.170.160.150.14

1.160.880.710.600.520.470.420.380.350.320.300.290.28

1.371.080.890.750.660.590.540.490.450.420.400.380.36

1.471.170.970.840.740.660.600.560.520.490.460.450.42

1.511.221.020.890.790.710.650.600.560.530.510.490.46

1.541.261.060.930.820.750.680.630.590.560.540.520.50

1.571.301.110.970.870.780.720.670.620.590.560.530.51

1.611.351.161.020.910.820.750.690.650.610.580.550.52

1.641.381.181.050.940.850.770.710.660.630.600.570.54

1.641.381.181.050.940.850.770.710.670.640.610.580.55

Table A10.7.2.3BValues of $t

Sp,mm

SQ,mm

Number of rows, nR

2 4 6 8 10 12 14 16 18 20

25

32

40

50

12.515.025.032.040.0

12.515.025.032.040.0

12.515.025.032.040.0

12.515.025.032.040.0

1.001.111.682.032.37

0.941.051.581.902.23

0.870.971.481.782.08

0.750.841.271.541.80

1.001.061.361.541.72

0.930.991.271.441.61

0.870.921.181.341.50

0.750.791.001.141.27

1.001.041.231.341.46

0.930.971.151.261.36

0.870.901.071.171.27

0.750.770.911.001.09

1.001.021.141.221.29

0.930.951.071.141.21

0.870.891.001.061.13

0.750.760.850.910.97

1.001.021.091.141.18

0.930.951.021.061.11

0.870.880.960.991.04

0.750.760.810.850.89

1.001.011.081.101.14

0.930.941.001.021.06

0.870.880.930.960.99

0.750.760.790.820.86

1.001.011.081.091.12

0.930.941.001.011.04

0.880.880.920.940.97

0.750.760.790.820.85

1.001.011.061.071.10

0.930.940.980.991.02

0.870.880.920.930.95

0.750.750.780.800.83

1.001.011.041.061.08

0.930.940.980.981.00

0.870.880.910.930.94

0.750.750.780.800.82

1.001.011.031.051.06

0.930.940.970.981.00

0.870.880.900.920.93

0.750.750.770.790.81


August 2001 195

Table A10.7.2.3GValues of $tp

SQ,mm

Sp,mm

Number of rows, nR

2 4 6 8 10

15

25

32

40

2540

25324050

25324050

25324050

1.291.76

1.001.181.361.72

0.820.971.121.42

0.630.750.871.11

1.251.61

1.001.131.271.53

0.840.961.071.29

0.680.770.861.04

1.241.49

1.001.101.201.40

0.850.941.031.20

0.700.780.840.98

1.231.45

1.001.091.171.34

0.860.931.001.15

0.710.770.830.95

1.231.40

1.001.071.141.28

0.860.930.981.10

0.710.760.820.92

Table A10.7.2.3HValues of $D

ep

$D

ep

$D(nC–1)SQ (nC–1)SQ

0.10.20.30.40.50.60.70.80.9

0.2750.4330.5380.600.650.690.730.770.80

1.01.21.41.61.82.02.42.8 and more

0.830.880.920.950.970.980.991.00

Note: For eP/[(nC–1)SQ] between 0.1 and 0.3, $D is given to three significantdigits due to the sensitivity in this range.


196 August 2001

A10.9.3.2 Lateral Deformation of Nailed and Spiked Wood-to-WoodJointsFor specified loads, P, not greater than nu/3, the lateral deformation of nailed and spiked joints may beestimated from

) = 0.5dKm(P/nu)1.7

where) = lateral deformation, mmd = nail diameter, mmKm = service creep factor (Table A10.9.3.2) P = specified load per nail or spike, Nnu = unit lateral strength resistance (Table 10.9.4), N

Table A10.9.3.2Service Creep Factors, Km, for Nail and Spike Joints

Load durationclass

Moisture condition

Nailed dry,loaded dry

Nailed wet,loaded dry

Nailed wet,loaded wet

PermanentStandardShort

1.51.21.0

2.01.51.2

3.02.01.5

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