Architectural Structures Arch 241 - Nov 2008Architectural

Architectural Structures Arch 241 - Nov

2008Architectural Structures – Arch 241

McGill School of Architecture

17 November 2008

Wood-Frame Construction and Engineered

Wood Products – an introduction

Patrice Tardif Consulting 1

Architectural Structures

Arch 241


Montreal, Quebec

17 November 2008

AN INTRODUCTION

Wood Frame Construction and

Engineered Wood Products

Patrice R. Tardif, B. Arch.

Life cycle of building materials

Why wood?

Introduction to wood frame construction

and wood products

Engineered wood products, their make-up,

attributes and uses

Overview

Intuit – Office, development centre,

call centre

Edmonton, Alberta (2002)




17 November 2008




Blue Mountain Ski Resort

Colllingwood, Ontario

Dollarama – Le Huard

Quincaillerie Home Hardware

Chibougamau, Québec (2003)

Jackson Triggs Winery

Niagara-on-the-Lake, Ontario (2001)

xxxPoste de pompiers

Alberta (2001)




17 November 2008




Bibliothèque de Val Cartier

Val Cartier (2002)

Gene H. Kruger Pavilion, Laval University

Sainte-Foy (2005)




17 November 2008




Limoges Concert Hall

Limoges, France (2006)

Albert Mianscum Memorial Sports

Complex

Oujé-Bougoumou (2002)

Complexe multi-sports de Laval

Laval (2005)

xxx

Mountain Equipment Co-op

Montréal, Québec (2003)

Magasin d’articles de sport Gerrick’s

Cranbrook, Colombie-Brittanique (2005)




17 November 2008




Club de golf Saint-Prime-sur-le-lac

Saint-Prime, Québec (2003)

Parc des Hautes, Sépaq

Charlevoix, Québec




17 November 2008




Gare Intermodale de Saint-Jérôme

Saint-Jérôme (2004)

Brentwood Skytrain Station

Burnaby, B.C. (2001)

Credit Valley Hospital

Mississauga, Ontario (2004)

Thunder Bay Hospital

Thunder Bay, Ontario (2002)




17 November 2008




Cathedral of Christ the Light

Oakland, California (2008)

An introduction to life cycle analysis (LCA)building materials from “cradle to grave”

LCA evaluation of building materialsresource extraction

manufacturing requirements

on-site construction

occupancy / maintenance

demolition

recycling / reuse / disposal

Certification programsexamples

LEED

Life Cycle of Building Materials

LIFE CYCLE ANALYSIS (LCA)

LCA is a tool that can be used to assess the burdens

placed on the environment by a product through all

stages of its life.

An introduction to Life Cycle Analysis

“Cradle to Grave”

Two main aspects to LCA:

Data acquisition

Data analysis

An introduction to Life Cycle Analysis cont’




17 November 2008




LCA evaluation of building materials

Sawmill

Recycling

CO2

CO2

Panel

Manufacturing

Biomass

Facility

Extraction

“Cradle to Grave” resource

extraction

manufacturing

requirements

on-site

construction

occupancy /

maintenance

demolition

recycling / reuse /

disposal

resource extraction

LCA evaluation of building materials

resource extraction cont’

LCA evaluation of building materials cont’

manufacturing requirements





17 November 2008




on-site construction


on-site construction cont’


occupancy / maintenance


demolition





17 November 2008




recycling / reuse / disposal


Life cycle assessments look at environmental

impacts, such as:

• acid rain • air pollution • health

• smog • indoor air quality • water intake

• global warming • habitat alteration • ecological toxicity

• ozone depletion • fossil fuel depletion

According to LCA, wood products are the most

environmentally responsible construction materials

when taking into consideration all of these factors.



Two main aspects to LCA:

Data acquisition

Data analysis

Interpretation

Value judgements

product standards (ANSI, CGSB, ISO)

certified forest management practices CSA

FSC

SFI

environmentally preferable products Green Seal

Green Cross

EPP

performance measurement tools BREEAM (Green Leaf) Green Globes

LEED GB Tool

Certification programs




17 November 2008




Why wood?

Renewable and sustainable

Durable

Environmentally responsible (manufacturing)

Reduces global greenhouse gas emissions

Thermally efficient

Subjective properties

renewable and sustainable

Over 600 million

seedlings are

planted in Canada

each year

Why wood?

6%16%

21%26%

29%40%

60%63%64%66%68%

82%86%

90%91%

0% 20% 40% 60% 80% 100%

United Kingdom

China

New Zealand

United States

Indonesia

Russian Federation

Sweden

CANADA

Source : FAO State of the World`s Forests 2005

Renewable and sustainable

The rate of growth in Canada’s commercial

forests is equivalent to:

- 50,354 houses a day

- 2,098 houses an hour

- 35 houses a minute

Renewable and sustainable cont’




17 November 2008




0

20

40

60

80

100

120

140

1999 2000 2001 2002 2003 2004 2005 2006 2007

End of year

CSA

SFI

FSC

78.0 – CSA

36.1 – SFI

24.4 – FSC

Source: Canadian Sustainable Forestry

Certification Coalition – December 2007

Sustainable Forest Management certification (SFM)

in Canada, 1999 – 2007 (millions of ha)


138.5

42.2

22.517.9 17.5

9.2 7.7 5.8 4 3.70.71.9

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

CANADA

Éta

ts-U

nis

Finlan

de

Suè

de

Fédé

ratio

n Rus

se

Aus

tralie

Alle

man

ge

Bré

sil

Malay

sie

Fran

ce

Chile

Mex

ique


Source: Canadian Sustainable Forestry Certification Coalition – December 2007

SFM certification in Canada

and internationally,

December 2007

(millions of ha)

Norway : “Borgund” – stave church

12th century

Japan : “Todaiji” built in 752 – the

largest wood building in the world –

most recent section built in 1692

DurableBanc de pêche de Pasbébiac

– “Entrepot le Boutillier” –

built in ~ 1840




17 November 2008




7

Wood Steel Concrete

Energy Use

(GJ x 108)

4

5.5

Why wood? cont’


durable

environmentally responsible (manufacturing)

Uses less energy to manufacture

Equivalent CO2

(Tonnes) Wood Steel Concrete

10501300

750

AIR


durable



Contributes less to air pollution

Environmentally responsible

Wood Steel ConcreteIndex Value x 108

165

1 5

WATER


durable



Contributes less to water pollution

Environmentally responsible cont’

Wood Steel ConcreteIndex Value x 105

60

3530


durable



Contributes less to air and water pollution

Resource extraction requirements less onerous

Environmentally responsible cont’




17 November 2008





durable


52 % dimension lumber & other wood products ;

30 % chips for pulp and paper ;

10 % bark for energy & mulch ;

8 % shavings for particleboard,

MDF, energy and mulch.


Contributes less to air and water pollution

Resource extraction requirements less onerous

Efficient use of raw resource

Environmentally responsible cont’Why wood? cont’


durable


reduces global

greenhouse

gas emissions

A typical 216 sq. m. (2,400

sq. ft) wood-frame house

holds 28.5 tonnes of carbon

dioxide, an amount equal to

the emissions of a small car

over seven years.

R value for wood = 1.5/in.

R value for steel = .0024/in.

R value for concrete = .08/ in.

Why wood? cont’


durable


reduces global greenhouse gas emissions

thermally efficient


durable



thermally efficient cont’

0

1

2

3

4

5

Assembly R Values

Wood 2x4

Steel 2x4

Concrete Block 6"

Thermally efficient




17 November 2008




Why wood? cont’


durable


subjective properties warmth

aesthetics


thermally efficient

LCA examines the entire life cycle of a product, a

process or an activity . . .

Why wood? cont’

Embodied and Operating Energy

Steel Concrete

Energy Use 12% 20%

Greenhouse 15% 29%

Air Pollution 10% 12%

Water Pollution 300% 225%

Resource Use 7% 50%

Solid Waste 6% 16%

Why wood? cont’

For a typical building with a life expectancy of 20 years.

Wood – frame Construction




17 November 2008




Vertical load path:

Lateral load path:

Wood – frame Construction

live

dead

snow

wind

seismic

Post and Beam construction

Prefabricated or Manufactured construction

Light-frame construction

Wood-Frame Construction Techniques:

Wood – frame Construction cont’

Main Structural Elements:

Secondary Structural Elements:

Wood – frame construction cont’

Columns

Beams

Joists

Sheathing

Decking

Closely spaced members, combined with sheathing or

decking, form the structural elements of the building –

elements used are dimension lumber sized (2 x 4’s,

2 x 6’s, etc.)

2 basic framing methods

Light-frame Construction

Balloon framing

Platform framing




17 November 2008




Sheathing

Exterior

finish

Gypsum wallboard

Flooring

Insulation


The wall studs are

continuous for the

building’s height

Balloon framing

The wall studs are

continuous for the

building’s height

Balloon framing cont’

Floor supports are

let into the wall

framing members

Platform framing

Floor assembly built

separately from walls

and extends to outer

edge of walls




17 November 2008




Platform framing cont’

Floor assembly built

separately from walls

and extends to outer

edge of walls

Provides working

surface for

subsequent levels

Widely-spaced sawn timbers

provide structural support –

diagonal bracing or

other support is required to

resist lateral loads.

Post and Beam Construction

Widely-spaced sawn timbers provide structural

support – diagonal bracing or other support is

required to resist lateral loads

diagonal bracing or other support is required to resist

lateral loads

Post and Beam Construction cont’

large members connected

using high capacity type

connections, etc.

Elements or systems are constructed off-site in

controlled environments.

Prefabricated or Manufactured Construction




17 November 2008




Elements can be used in conjunction with more

conventional construction techniques, or entire

houses can be “manufactured” off-site, then

transported and assembled on-site.

Prefabricated or Manufactured Construction cont’

Advantages:

integrated design approach

quality of the building envelope

controlled environment, easier to assure quality of

materials and construction techniques

speed of assembly

Prefabricated or Manufactured Construction cont’

Main Structural Elements:


Columns

Beams

Joists Engineered wood products

Timber

Specialty lumber

Dimension lumber

Products used for Main Stuctural Elements




17 November 2008




Dimension lumber

- 4” thick (100 mm) (nominal)

- visually graded and stamped as meeting

standardized grading rules (NGRDL and NLGA)

- Approved by the

Canadian lumber

standards accreditation

board

Main Stuctural Elements cont’ Main Stuctural Elements cont’

Dimension lumber

Specialty lumber

- Machine stress-rated (MSR) – visually graded and

mechanically tested

Main Stuctural Elements cont’

Dimension lumber

Specialty lumber

- Machine stress-rated (MSR) – visually graded and

mechanically tested

- Finger-joined lumber –

machined profiles

end-glued

- minimum thickness of 6”

(152 mm)

- visually graded and stamped as

meeting NGRDL and NLGA

standardized grading rules

- Canadian grades and species

meet CNBC requirements

and CSA O86


Dimension lumber

Specialty lumber

Timber




17 November 2008




- Structural composite lumber (SCL)

- Wood I-joists

- Light-frame trusses

- Glulams


Dimension lumber

Specialty lumber

Timber

Engineered wood products

Secondary Structural Elements:


Sheathing

Decking

Products used for Secondary Stuctural Elements

Decking

Sheathing

- Plywood

- Oriented strand board (OSB)

Secondary Stuctural Elements cont’

Sheathing




17 November 2008




- Dimension lumber with tongue and grooved profile

- 3 thicknesses ranging from 1.5” ( 38 mm) to 3.5” (89 mm)

Sheathing

Decking or planking

Secondary Stuctural Elements cont’

An Engineered Wood Product (EWP) is a product

that has gone through a process to provide

better or more predictable properties.

more design flexibility

longer spans

greater load carrying capacity

can use the entire tree, no matter what the species, the

shape or the size

a good use of raw resource with less construction waste

Engineered Wood Products

Typical engineered wood products in wood-frame

construction:

SCL trusses

glulams plywood

wood I-joists OSB

Engineered Wood Products cont’

Structural panel made from thin softwood veneers

(plies) in alternating cross-oriented layers that are

glued together under heat and pressure using

waterproof adhesives.

must be certified to product standards and stamped as

such to be accepted by building codes

odd # of plies that are

symmetrical about the

centreline

sanded or unsanded

tongue & grooved or

square-edged

Plywood




17 November 2008




Plywood – Attributes

can be treated for added properties

(resistance to fire, insects, decay)

certified for exterior applications

Plywood – Uses

floor, roof, and wall sheathing,

floor underlayment,

concrete formwork,

box beams

stressed-skin panels

preserved wood foundations

Plywood cont’

Structural panel made from successive layers of strands

that are bonded together under heat and

pressure with either waterproof adhesives or

equivalent binders and wax.

strands oriented in long direction of the panel in outer

layers and typically cross-oriented in the core

must be certified to product

standards and stamped to be

accepted by building codes

tongue& grooved or

square-edged

Oriented Strand Board (OSB)

OSB – Attributes

added strength and stiffness in the

length of the panel

high shear value

available in many different sizes and lengths

not recommended for exposed exterior

applications

OSB – Uses

floor, roof and wall sheathing

structural insulated panels

wood I-joist webs

concrete formwork

siding

Oriented Strand Board (OSB) cont’

Proprietary engineered wood products, each

with its own design values:

Structural Composite Lumber (SCL)

Parallel Strand Lumber (PSL)

Laminated Veneer Lumber (LVL)

Laminated Strand Lumber (LSL)




17 November 2008




glued products using exterior, waterproof resins

similar structural capabilities

need individual certification to be accepted in building

codes

manufacturers supply load tables and installation

recommendations, as well as assist with layout drawings

and sizing of members

need engineer’s approval or stamp

Structural Composite Lumber (SCL) cont’

PSL is an SCL that consists of strands of veneers

glued together under pressure with the strands

oriented along the length of the piece.

beams typically available in 1-3/4” ( 44.5 mm) to 7” (178 mm)

thicknesses and can be sawn to

any dimension

manufacturers supply load

tables and installation

recommendations, as well as

assist with layout drawings

and sizing of members –

ultimately need engineer’s

stamp

Parallel Strand Lumber (PSL)

PSL – Attributes

consistent properties

resistant to seasonal stresses

high load-carrying capacities

suited to uses where appearance is important

PSL – Uses

beams, columns (post & beam)

beams, headers lintels (light-frame)

heavy timber construction

in trusses

Parallel Strand Lumber (PSL) cont’

LVL is an SCL that is manufactured by curing an

assembly of glued veneers together in a heated press

to form billets that are subsequently cut to the depths

required.

grain of veneers oriented parallel

to the length of the piece

wider members may be built-up

available up to 80’ (24 m) in length

Laminated Veneer Lumber (LVL)




17 November 2008




LVL – Attributes

strong when edge loaded

strong when face loaded

dimensional stability

high strength & reliability, low variability

LVL – Uses

flanges for wood I-joists

scaffold planking

stock headers and beams

columns, wall studs, in trusses

Laminated Veneer Lumber (LVL) cont’

LSL is an SCL that is manufactured from long strands

of wood, oriented parallel to each other and glued.

Strands are of uniform dimension and LSL is

manufactured to a consistent moisture content.

Laminated Strand Lumber (LSL)

LSL – Attributes

LSL – Uses

uniform and consistent properties

transfer lateral and vertical bearing

forces (rimboards)

dimensionally stable

rimboard – an integral

component of engineered

wood systems that

support wall loads and tie

floor joists together

studs (22’ – 6.7 m)

Laminated Strand Lumber (LSL) cont’

Glulams are manufactured by gluing together

dimension lumber laminations with waterproof

adhesives. The lumber is first visually and

mechanically graded, then sorted for strength and

stiffness into lamstock grades.

lamstock is end-joined or butted

then arranged in horizontal layers

and glued under pressure

available in stress and appearance

grades

available balanced & unbalanced

MC range for lamstock before assembly: 7-15%

Glued-Laminated Timber (Glulams)




17 November 2008




Stress grade defines strength of the material. Higher

quality lamstock is located in high stress areas.

Appearance grade defines the amount of patching

and finished work done to the exposed surfaces after

laminating (industrial, commercial, quality).

Balanced beam: used for

continuous spanning or cantilever

applications.

Unbalanced beam: used for simple

spans.

Glued-Laminated Timber (Glulams) cont’

Glulams – Attributes

Glulams – Uses

large members, many shapes and sizes – can be curved,

tapered and cambered

suitable for interior or exterior use

lower MC of lamstock leads to less shrinkage and

checking in service

columns, beams, headers, girders

used when structure left exposed

heavy trusses

Glued-Laminated Timber (Glulams) cont’

Prefabricated wood I-joists are made by using exterior-

rated waterproof adhesives to glue pre-dried solid sawn

lumber, MSR or LVL flanges to a plywood or OSB panel

web.

each manufacture produces product with unique strength and

stiffness characteristics using different combinations of flange

and web materials with different connection details

manufacturers’ supply allowable load

and span tables

need individual certification to be

accepted in building codes

suppliers stock standard joist hangers

and other connection hardware

Wood I-joists

Wood I-joist – Attributes

dimensionally stable, lightweight with uniform stiffness and

strength and known engineering properties

high strength to weight ration – can be manually installed

can be cut and worked using common wood working tools

wide flanges allow for good fastening surface for sheathing

factory pre-punched knock-out holes in web facilitate

installation of electrical services

Wood I-joists cont’




17 November 2008




Wood I-joist – Uses

well suited for longer span floor and roof joist applications

economical alternative to open-web steel joists

Wood I-joists cont’

Trusses use a triangular arrangement of webs and

chords to transfer loads to reaction points.

light-frame trusses

typically prefabricated by connecting 2” (50 mm) (nominal)

dimension lumber together with metal truss plates

2 Truss categories

heavy-timber trusses

heavy timber or EWP (glulams, PSL)

connected with specialty metal

connectors

Trusses

made from dimension lumber of various sizes

chords and webs connected using toothed galvanized steel

connector plates hydraulically pressed into precut lumber at

joints – plates must conform to specific standard requirements

truss plate manufacturer typically

engineers trusses on behalf

of truss fabricator

each proprietary product requires

individual certification

Light-frame Trusses

Light-frame trusses - Attributes

unlimited size and shape options – may be manufactured to

suit any roof style

Light-frame Trusses cont’




17 November 2008




Light-frame trusses – Attributes cont’

all trusses are custom designed

economical (ease of fabrication, simplified erection procedures)

flexibility in layout

long spanning

capabilities


Light-frame trusses – Uses

residential and commercial

applications


Open-web joists are either metal plate connected,

glued or metal-webbed trusses –

parallel chord trusses.

generally custom designed

proprietary properties and installation requirements

specific loadings and other structural requirements to

be clearly identified for proper design of each system

Open-web Joists

Open-web joists – Attributes

often more economical than open-web steel joists

electrical, plumbing, heating and air conditioning services

may be placed between the truss chords (must be specified)

can be supported on the top or bottom chord

can have built-in camber

permits large bay sizes with no intermediate support

Open-web joists – Uses

floor or roof joists

Open-web Joists cont’




17 November 2008




EWP’s play an important role in wood-frame

construction, both on-site and in prefabricated

or manufactured systems.

great design flexibility

easy to handle, lead to fewer cut-offs on site

more efficient use of our forest reserves

lack of defects and controlled MC of individual elements

afford dimensional stability and high strength

high weight to strength ratio

economical, durable, lightweight alternative to solid sawn

lumber

Engineered Wood Products cont’

The basics …

choose materials that are suitable for the intended

application

structural elements and systems used must meet

the loading requirements

interior or exterior use?

determine spans and optimum member profiles

consider material costs, including transportation to

the site

form and intended function of a building may

dictate certain building materials

Designing with Wood

Material is selected …

specify certified products that adhere to 3rd party

certification program

verify local building code requirements

insure product availability and support from

manufacturer

use appropriate connection detailing

use appropriate building envelope detailing

insure adequate site supervision

Designing with Wood cont’




17 November 2008




(also)

www.forest.ca

www.wood-works.org

www.woodworks-software.com

www.woodmags.com

www.durable-wood.com

Appropriateness of wood as a construction material

Life cycle analysis of building materials

Wood-frame construction

primary and secondary elements

different framing options

Introduction to EWPs, their uses and attributes

General design considerations when designing

with wood

Summary

Canadian Wood Council

APA – the Engineered Wood Association

Faherty and Williamson

ATHENA Institute

Wood WORKS!

Sustainable Forestry Initiative

www

Acknowledgements

Documents

Architectural Structures Arch 241 - Nov 2008Architectural