ISIS Manual - FRP Concrete Reinforcement

8/2/2019 ISIS Manual - FRP Concrete Reinforcement

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ReinforcingConcrete Structures withFibre Reinforced Polymers

ISIS CANADAThe Canadian Network of Centres of Excellence on Intelligent Sensing for Innovative StructuresLe rseau canadien de Centres d'excellence sur les innovations en structures avec systmes de dtection intgrs

DESIGN MANUA

Design Manual No. 3September 2001

www. i s i s c a n ada . c om


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ReinforcingConcrete Structures withFibre Reinforced Polymers

ISIS CANADAThe Canadian Network of Centres of Excellence on Intelligent Sensing for Innovative StructuresLe rseau canadien de Centres d'excellence sur les innovations en structures avec systmes de dtection intgrs

DESIGN MANUA

Design Manual No. 3September 2001


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Reinforcing Concrete Structures with Fibre Reinforced PolymersDesign Manual No. 3ISBN 0-9689006-6-6

ISIS Canada CorporationSeptember 2001

ISIS Canada, Intelligent Sensing for Innovative Structures, A Canadian Network of Centres of Excellence,227 Engineering Building, University of Manitoba, Winnipeg, Manitoba, R3T 5V6, CanadaE-mail: [email protected] http://www.isiscanada.com

To purchase additional copies, refer to the order form at the back of this document.

This publication may not be reproduced, stored in a retrieval system, or transmitted in any form or by any meanswithout prior written authorization from ISIS Canada.

The recommendations contained herein are intended as a guide only and, before being used in connection withany design, specification or construction project, they should be reviewed with regard to the full circumstances ofsuch use, and advice from a specialist should be obtained as appropriate. Although every care has been taken inthe preparation of this Manual, no liability for negligence or otherwise will be accepted by ISIS Canada, themembers of its technical committee, peer review group, researchers, servants or agents. ISIS Canada publicationsare subject to revision from time to time and readers should ensure that they possess the latest version.


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Acknowledgements

This document has been prepared by:*Dagmar Svecova University of Manitoba

Sami Rizkalla North Carolina State UniversityGamil Tadros SPECO Engineering Ltd.

Aftab Mufti University of Manitoba*(This document was primarily prepared by Dr. Svecova.)

Technical Committee:Brahim Benmokrane Universit de SherbrookeIvan Campbell Queens UniversityMamdouh El-Badry University of Calgary

Amin Ghali University of CalgaryKenneth Neale Universit de SherbrookeNigel Shrive University of CalgaryDagmar Svecova University of Manitoba

Gamil Tadros SPECO Engineering Ltd.

Peer Review:Paul Langohr Stantec Consulting Ltd.

Amin Ghali University of Calgary

(These individuals reviewed only those sections of the manual consistent with their expertise)

Technical Editor: Leslie Jaeger, Professor Emeritus, Dalhousie University

Design and Production: Jennifer Redston, ISIS Canada

Editor: Jamie Zukewich, ISIS Canada

Author: Sami Rizkalla University of Manitoba

(Currently at North Carolina State University)

Co-Author: Aftab Mufti University of Manitoba

ISIS Canada is a member of the Networks of Centres of Excellence (NCE) program, administered and funded bythe Natural Sciences and Engineering Research Council (NSERC), the Canadian Institutes of Health Research(CIHR) and the Social Sciences and Humanities Research Council (SSHRC), in partnership with Industry Canada.


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TABLE OF CONTENTS

1 Preface1.1 Preface .....................................................................................................................................................1.1

2 ISIS CANADA

2.1 Overview.................................................................................................................................................2.12.2 Research Program.................................................................................................................................. 2.12.3 Teaching Activities ................................................................................................................................2.3

3 USING THIS MANUAL3.1 General Requirements...........................................................................................................................3.13.2 Drawings and Related Documents .....................................................................................................3.13.3 Code References ....................................................................................................................................3.1

4 FRP REINFORCING MATERIALS

4.1 Definitions .............................................................................................................................................. 4.14.2 General ...................................................................................................................................................4.14.3 FRP Constituents................................................................................................................................... 4.2

4.3.1 Fibres ........................................................................................................................................ 4.24.3.2 Resins........................................................................................................................................ 4.4

4.4 FRP Reinforcing Products and Material Properities........................................................................4.44.4.1 Manufacturing Process...........................................................................................................4.54.4.2 Coefficient of Thermal expansion of FRP .........................................................................4.64.4.3 Effect of High Temperature.................................................................................................4.64.4.4 Bond Properties of FRP Reinforcing Bars ......................................................................... 4.74.4.5 Fatigue of FRP Reinforcing Bars ......................................................................................... 4.74.4.6 Creep and Relaxation of FRP Reinforcing Bars ................................................................4.8

4.5 Durability of FRP Reinforcing Bars ...................................................................................................4.8

4.6 Commercially Available Reinforcing Bars .........................................................................................4.94.6.1 Glass Fibre Reinforced Polymer Products .........................................................................4.94.6.2 Carbon Fibre Reinforced Polymer Products....................................................................4.144.6.3 Aramid Fibre Reinforced Polymer Products....................................................................4.164.6.4 Hybrid Fibre Reinforced Polymer Products ....................................................................4.16

5 DESIGN PROCESS5.1 Definitions .............................................................................................................................................. 5.15.2 Limit States Design................................................................................................................................5.15.3 Load Factors and Loading Combinations for Buildings.................................................................5.1

5.3.1 Load Combinations ................................................................................................................5.2

5.3.2 Load Factors............................................................................................................................5.35.3.3 Importance Factor..................................................................................................................5.35.3.4 Resistance Factors...................................................................................................................5.3

5.4 Load Factors and Loading Combinations for Bridges ....................................................................5.35.4.1 Load Combinations ................................................................................................................5.45.4.2 Resistance Factors...................................................................................................................5.5

5.5 Constitutive Relationships for Concrete............................................................................................5.55.5.1 Tensile Strength ...................................................................................................................... 5.55.5.2 Compressive Behaviour.........................................................................................................5.5


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5.5.3 Modulus of Elasticity .............................................................................................................5.75.6 Constitutive Relationship for FRP......................................................................................................5.8

5.6.1 Tensile Strength and Modulus of Elasticity........................................................................5.85.6.2 Compressive Strength and Modulus of Elasticity .............................................................5.9

6 DESIGN FOR FLEXURE6.1 Definitions .............................................................................................................................................. 6.16.2 General ....................................................................................................................................................6.16.3 Strain Compatibility...............................................................................................................................6.26.4 Modes of Failure....................................................................................................................................6.2

6.4.1 Balanced Failure Reinforcement Ratio................................................................................6.26.4.2 Failure Due to Crushing of Concrete..................................................................................6.56.4.3 Tension Failure........................................................................................................................6.7

6.5 Cracking Moment ................................................................................................................................6.106.6 Minimum Flexural Resistance............................................................................................................6.106.7 Beams with FRP Reinforcement in Multiple Layers......................................................................6.116.8 Beams with Compression Reinforcement .......................................................................................6.11

6.9 Examples...............................................................................................................................................6.116.9.1 Analysis of a Rectangular Beam with Tension Reinforcement .....................................6.11

7 SERVICEABILITY LIMIT STATES7.1 Definitions .............................................................................................................................................. 7.17.2 General ....................................................................................................................................................7.17.3 Cracking...................................................................................................................................................7.2

7.3.1 Crack Width.............................................................................................................................7.37.3.2 Permissible Crack Width .......................................................................................................7.4

7.4 Deflection................................................................................................................................................7.47.4.1 Minimum Thickness of Members Reinforced with FRP ................................................. 7.47.4.2 Examples for Determining Minimum Thickness and Span-to-Deflection Ratio ........7.6

7.4.2.1 Minimum Thickness of One-Way Slab Reinforced with FRP .....................7.67.4.2.2 Verfication of Span-to-Deflection Ratio..........................................................7.6

7.4.3 Effective Moment of Inertia Approach..............................................................................7.77.4.4 Curvature Approach...............................................................................................................7.97.4.5 Deflection Under Sustained Load......................................................................................7.107.4.6 Permissible Deflection.........................................................................................................7.10

7.5 Example of Deflection Calculation...................................................................................................7.11

8 DEVELOPMENT, ANCHORAGE AND SPLICING OF REINFORCEMENT8.1 Definitions .............................................................................................................................................. 8.18.2 General ....................................................................................................................................................8.1

8.3 Development Length and Anchorage................................................................................................8.18.4 Splicing of FRP Reinforcement...........................................................................................................8.2

9 DEFORMABILITY9.1 Definitions .............................................................................................................................................. 9.19.2 Deformability..........................................................................................................................................9.1


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10 CHARTS FOR FLEXURAL DESIGN10.1 Definitions ............................................................................................................................................10.110.2 Design Aids for Rectangular Concrete Sections.............................................................................10.110.3 Concepts Used for the Design Charts..............................................................................................10.1

10.3.1 Group A Curves....................................................................................................................10.110.3.2 Group B Curves....................................................................................................................10.2

10.3.3 Group C Curves....................................................................................................................10.410.4 Use of Design Charts ..........................................................................................................................10.4

10.4.1 Design Example....................................................................................................................10.510.5 Design Charts .......................................................................................................................................10.7

11 SHEAR DESIGN11.1 Definitions ............................................................................................................................................11.111.2 General ..................................................................................................................................................11.111.3 Modes of Failure ..................................................................................................................................11.211.4 Beams Without Web Reinforcement................................................................................................11.211.5 Beams with FRP Web Reinforcement .............................................................................................11.3

11.5.1 Types of FRP Stirrups..........................................................................................................11.311.5.2 Detailing of FRP Stirrups....................................................................................................11.311.5.3 Minimum Amount of Shear Reinforcement ....................................................................11.411.5.4 Maximum Strain in FRP Stirrups.......................................................................................11.5

11.6 Shear Resistance of FRP Reinforced Beams...................................................................................11.511.7 Shear Design Example........................................................................................................................11.611.8 Shear Resistance of FRP Reinforced Beams Using Shear Friction .............................................11.9

11.8.1 Fundamentals ........................................................................................................................11.911.8.2 Design Procedure for Use in Regions of Uniform Stirrup Spacing ...........................11.1011.8.3 Design Example..................................................................................................................11.12

12 PLACEMENT OF REINFORCEMENT AND CONSTRUCTABILITY

12.1 Definitions ............................................................................................................................................12.112.2 Spacing of Longitudinal Reinforcement ..........................................................................................12.112.3 Concrete Cover ....................................................................................................................................12.212.4 Constructability....................................................................................................................................12.2

13 CASE STUDIES13.1 Crowchild Bridge, Alberta..................................................................................................................13.113.2 Halls Harbour Wharf, Nova Scotia..................................................................................................13.113.3 Joffre Bridge, Qubec .........................................................................................................................13.213.4 Taylor Bridge, Manitoba.....................................................................................................................13.3

14 NOTATION10.1 Notation ................................................................................................................................................14.1

15 GLOSSARY

16 REFERENCES


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Table of Contents

APPENDIX A - RESOURCESA.1 Resources ...............................................................................................................................................A.1

APPENDIX B DESIGN TABLESB.1 Design Tables........................................................................................................................................ B.1

APPENDIX C - EXAMPLEC.1 Design of a Rectangular Beam with Tension Reinforcement .......................................................C.1

APPENDIX D CONVERSION FACTORSD.1 Conversion Factors ..............................................................................................................................D.1

ISIS CANADA DESIGN MANUALS ORDER FORM


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Figures

Figure 4.1 Available shapes of FRP products

Figure 4.2 Stress-strain relationships for fibrous reinforcement and matrix

Figure 4.3 Pultrusion process

Figure 4.4 Effect of increased temperature on the strength of Leadline

Figure 4.5 C-Bar

Figure 4.6 ISOROD

Figure 4.7 NEFMAC

Figure 4.8 ROTAFLEX

Figure 4.9 LEADLINE

Figure 5.1 Stress-strain relationship for concrete

Figure 5.2 Stress-strain relationship of FRP materials

Figure 6.1 Nominal failure at balanced condition

Figure 6.2 (a) Strain, and (b) Stress distribution at ultimate (concrete crushing)Figure 6.3 (a) Strain, and (b) Stress distribution at ultimate (rupture of FRP)

Figure 6.4 Equivalent stress-block parameter for concrete strengths of 20 to 60 MPa

Figure 6.5 Equivalent stress-block parameter for concrete strength of 20 to 60 MPa

Figure 6.6 Strain compatibility for section with multiple layers of FRP

Figure 6.7 Strain compatibility analysis

Figure 7.1 Depth of neutral axis

Figure 9.1 Deformability of FRP reinforced beams

Figure 10.1 Group A curvesFigure 10.2 (a) FRP reinforced cross-section; (b) Strain profile at service load; (c) Stress resultants at service load

Figure 10.3 Group B curves

Figure 10.4 Tension failure

Figure 10.5 Group C curves

Figure 10.6 Design chart for example 10.4.1

Figure 10.7 Design chart for ffrpu = 600 MPa and Efrp = 30 GPa (Nefmac, GFRP)

Figure 10.8 Design chart for ffrpu = 690 MPa and Efrp = 42 GPa (ISOROD, GFRP)

Figure 10.9 Design chart for ffrpu = 700 MPa and Efrp = 37 GPa (C-Bar, GFRP)

Figure 10.10 Design chart for ffrpu = 747 MPa and Efrp = 45 GPa (ISOROD, GFRP)

Figure 10.11 Design chart for ffrpu = 770 MPa and Efrp = 42 GPa (C-Bar, GFRP)

Figure 10.12 Design chart for ffrpu = 760 MPa and Efrp = 40.8 GPa (Aslan 100, 9mm, GFRP)





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Figures


Figure 10.17 Design chart for ffrpu = 1200 MPa and Efrp = 100 GPa (Nefmac, CFRP)

Figure 10.18 Design chart for ffrpu = 2250 MPa and Efrp = 147 GPa (Leadline, CFRP)

Figure 10.19 Design chart for ffrpu = 1596 MPa and Efrp = 111.1 GPa (ISOROD, CFRP)

Figure 11.1 Stirrup configurations (Shehata 1999)

Figure 11.2 Stirrup detailing

Figure 11.3 Definition of beam cross-section

Figure 12.1 Selection of concrete cover based on bar diameter and coefficient of thermal expansion

Figure 12.2 Selection of concrete cover based on bar diameter and concrete strength

Figure C.1 Cross-section

Figure C.2 Bar layout

Figure C.3 Strain distribtuion on section

Figure C.4 Stirrup layout


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Tables

Table 4.1 Typical Mechanical Properties of Fibres

Table 4.2 Chemical Resistance of Fibres (JSCE 1993, Banthia and McDonald 1996)

Table 4.3 Typical Properties of Thermosetting Resins

Table 4.4 Typical Mechanical Properties of FRP Reinforcing Bars

Table 4.5 Typical Coefficients of Thermal expansion for FRP Reinforcing Bars

Table 4.6 Tensile Fatigue Strength Results for FiBRA (ffrpu=1255Mpa, Tanigaki et al. 1989))

Table 4.7 Values of Factor F

Table 4.8 Chemical Composition (weight percentage) of C-Bar Reinforcing Rod (Marshall Industries

Composites Inc.)

Table 4.9 Properties of C-Bar, Grade B/Type 1 (Marshall Industries Composites Inc.)

Table 4.10 Geometric/Mechanical Properties of Bars Manufactured by Hughes Brothers

Table 4.11 Other Material Properties of Bars Manufactured by Hughes Brothers

Table 4.12 Mechanical/Physical Properties of Glass-Vinyl Ester or Polyester ISOROD

Table 4.13 Geometric Properties of ISOROD

Table 4.14 Material Properties of NEFMAC (Glass)

Table 4.15 Physical Properties of ROTAFLEX

Table 4.16 Geometric/Mechanical Properties of LEADLINE

Table 4.17 Physical Properties of LEADLINE

Table 4.18 Geometric Properties of ISOROD Carbon Vinyl Ester

Table 4.19 Material Properties of NEFMAC (Carbon)

Table 4.20 Properties of S & P Laminates

Table 4.21 Material Properties of NEFMAC (Aramid)

Table 4.22 Typical Properties of NEFMAC (Hybrid Reinforcing Grid)

Table 5.1 Resistance Factors for FRP

Table 5.2 Load Combinations for Bridges (Canadian Highway Bridge Deck Code)

Table 5.3 Load Factors for Bridges (Canadian Highway Bridge Deck Code)

Table 5.4 Compressive Stress-Strain Coefficients for Normal-Density Concrete

Table 6.1 Balanced Reinforcement Ratio for FRP Reinforced Concrete

Table 7.1 Minimum Thickness of Steel Reinforced Concrete (CSA-A 23.3.94)

Table 7.2 Maximum Permissible Deflections

Table 8.1 Type of Tension Lap Splice Required

Table 12.3 Cover of Flexural Reinforcement

Table B.1 Stress-Block Factors for 20 to 30 MPa Concrete




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Tables

Table B.4 Coefficient K for Calculation of Cracked Moment of Inertia of Rectangular Section

Table D.1 SI Units/US Customary Units


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PREFACE

1.1

1.1 PrefaceIn Canada, more than 40% of the bridges currently in use were built over 30 years ago. Asignificant number of these structures are in urgent need of strengthening, rehabilitation orreplacement. Many bridges, as well as other types of structures, are deficient due to the

corrosion of steel reinforcement and consequent break down of the concrete - a result ofCanadas adverse climate and extensive use of de-icing salts. In addition, many structures arefunctionally obsolete because they no longer meet current standards. The expensive cycle ofmaintaining, repairing and rebuilding infrastructure has led owners to seek more efficientand affordable solutions in the use of fibre reinforced polymers (FRPs). These lightweight,high-strength composite materials are resistant to corrosion, durable and easy to install.Glass and carbon FRPs are already increasing infrastructure service life and reducingmaintenance costs.

Infrastructure owners can no longer afford to upgrade and replace existing infrastructureusing 20th century materials and methodologies. They are looking for emerging newtechnologies such as FRPs, that will increase the service life of infrastructure and reduce

maintenance costs. Fibre reinforced polymers contain high-resistance fibres embedded in apolymer resin matrix. They are rapidly becoming the materials of choice over steel forreinforced concrete structures. Despite their relatively recent entry into civil engineeringconstruction, FRP reinforced concrete structures are gaining wide acceptance as effectiveand economical infrastructure technologies. Indeed, the most remarkable development overthe past few years in the field of FRPs has been the rapidly growing acceptance worldwide ofthese new technologies for an enormous range of practical applications.

Within the ISIS Canada Network of Centres of Excellence, much research has been conducted todevelop advanced technologies for creative new FRP-reinforced concrete structures. ISISCanadas approach takes into account aspects such as strength requirements, serviceability,performance, and durability. Glass and carbon FRPs can be used where longer, unsupportedspans are desirable, or where a reduced overall weight, combined with increased strength,could mean greater seismic resistance. A lightweight, FRP-reinforced structure can reducethe size and cost of columns and foundations whilst accommodating increasing demands ofheavier traffic loads. The goal is to optimize the use of FRP materials so that stronger,longer lasting structures can be realized for minimum cost.

Many of these innovative designs for new structures incorporate remote monitoring systemsusing the latest generation of fibre optic sensors. In the past, structures were monitored bytransporting measuring devices to the site each time a set of readings was required. By usingfibre optic sensors for remote structural health monitoring, an extensive amount of data canbe collected and processed without ever visiting the site. The ability to monitor and assessthe behaviour of concrete structures reinforced with carbon and/or glass FRPs will hastenthe materials widespread acceptance. Accurate monitoring is key to securing industrysconfidence in fibre reinforced polymers.

The content of this design manual focuses on reinforcing new concrete structures with fibrereinforced polymers. It is one in a series of manuals that cover the use fibre optic sensors formonitoring structures, guidelines for structural health monitoring, and strengtheningconcrete structures with externally-bonded fibre reinforced polymers. This design manual

will be expanded and updated as other design procedures are developed and validated.


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Reinforcing Concrete Structures

1.2


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ISIS CANADA

2.1

2.1 OverviewIntelligent Sensing for Innovative Structures (ISIS Canada) was launched in 1995 under theNetworks of Centres of Excellence (NCE) program. As part of this now ongoing federalprogram, ISIS Canada adheres to the overall objectives of supporting excellent research,

training highly qualified personnel, managing complex interdisciplinary and multi-sectoredprograms, and accelerating the transfer of technology from the laboratory to themarketplace. ISIS Canada is a collaborative research and development process linkingnumerous universities with public and private sector organizations that provide matchingcontributions to the funding supplied by the NCE. By weaving the efforts of severaluniversities into one cohesive program, this research gains all the advantages of sharing

world-class scientists and facilities. A close relationship with industry ensures that allresearch is commercially viable.

ISIS Canada researchers work closely with public and private sector organizations that havea vested interest in innovative solutions for constructing, maintaining and repairing bridges,roads, buildings, dams and other structures. This solution-oriented research is deemed

critical to Canadas future because of the massive problems associated with deterioration ofsteel-reinforced concrete infrastructure. The Canadian Construction Association estimatesthat the investment required to rehabilitate global infrastructure hovers in the vicinity of$900 billion dollars.

2.2 Research ProgramISIS Canada is developing ways to use high-strength fibre reinforced polymer (FRP)components to reinforce and strengthen concrete structures. The use of FRP is beingcombined with fibre optic sensor (FOS) systems for structural health monitoring.

Demonstration projects across the country further research and foster an environment inwhich ISIS technologies are adopted as common practice. Demonstration projects are

geared to achieving specific objectives such as rehabilitating the crumbling piers of a wharf,or building a precedent-setting bridge. The projects are always carried out on, or result in,functional operating structures. While there are many different applications of ISIS Canadatechnologies, three general attributes remain constant:

FRP products that are up to six times stronger than steel, one fifth the weight, non-corrosive and immune to natural and man-made electro-magnetic environments;

Fibre optic sensors (FOSs) that are attached to the reinforcement and imbedded instructures to gather real-time information;

Remote monitoring, whereby structural information can be interpreted using an

expert system and then transmitted to a computer anywhere in the world.


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2.2

Fibre Optic SensingThe ultimate goal is to ensure that FOSs become as user friendly to install as conventionalstrain gauges, but with increased sophistication.

The research program is based on a new sensing device formed within an optical fibre calleda Bragg Grating. ISIS has already installed short gauge length Fibre Bragg Grating (FBG)

sensors in new bridges to monitor slow changes over time as well as the bridge response topassing traffic.

This technology provides a new, unintrusive way of monitoring the impact of traffic andexcess loads, long-term structural health, structural components rehabilitated with FRP

wraps, and vibration frequency and seismic responses of structures. Notable benefits includereducing the tendency to over-design structures, monitoring actual load history, anddetecting internal weak spots before deterioration becomes critical.

Remote MonitoringRemote monitoring projects cover designing economical data acquisition and

communication systems for monitoring structures remotely. This includes developing asystem whereby the data can be processed intelligently in order to assess its significance. Bymodelling new structural systems, service life predictions can be made using the collectedsensing data.

To date, several bridges and structures across Canada have been equipped with fibre opticremote monitoring devices. A combination of commercially available and ISIS developedcomponents have been used in the measurement configurations. Both new and rehabilitatedstructures are currently being monitored. One of the major challenges is to develop astandardized intelligent processing framework for use with data records obtained from

various ISIS field applications.

Smart reinforcement is another development in remote monitoring. Using pultrusion

technology, FOSs can be built into FRP reinforcements. Smart reinforcements andconnectors eliminate the need for meticulous installation procedures at the work site,resulting in construction savings.

New StructuresCreative approaches to new FRP-reinforced structures are also being developed. Aspectssuch as strength requirements, serviceability, performance, and durability are examined. Theexperimental program includes building and testing full-scale or scaled-down models inorder to examine behaviour, and providing design guidelines for construction details for fieldapplications.

Glass fibre reinforced polymer (GFRP) and carbon fibre reinforced polymer (CFRP) can beused for reinforcing cast-in-place and precast concrete. The reinforcement can take theshape of rebars, stirrups, gratings, pavement joint dowels, tendons, anchors, etc. In bridgedesign, this material is used where longer, unsupported spans are desirable, or where areduced overall weight combined with increased strength could mean greater seismicresistance. A lightweight, FRP-reinforced structure can reduce the cost of columns andfoundations and can accommodate the increasing demands of heavier traffic loads.


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ISIS Canada

2.3

Research has led to field applications outfitted with the newest generation of FOS systemsfor remote monitoring. Accurate monitoring of internal strain is key to securinginfrastructure owners' confidence in the material and design configuration.

The practical significance of monitoring a structure is that changes which could affectstructural behaviour and load capacity are detected as they occur, thereby enabling important

engineering decisions to be made regarding safety and maintenance considerations.

Rehabilitated StructuresThe high strength and light weight of FRP and the fact that the material is now available inthe form of very thin sheets makes it an attractive and economical solution for strengtheningexisting concrete bridges and structures. In rehabilitation projects, FRP serves to confineconcrete subjected to compression, or improve flexural and/or shear strength, as anexternally bonded reinforcement.

There are numerous opportunities to apply this research because existing steel-reinforcedconcrete structures are in a continuous state of decay. This is due to the corrosive effects of

de-icing, marine salt, and environmental pollutants, as well as the long-term effects of trafficloads that exceed design limits.

FRP patching and wrapping is the state-of-the-art method for repair and strengthening ofstructures. This new technology will lead to the optimum maintenance and repair ofinfrastructure. Research projects include developing smart repair technologies whereby FOSsare embedded in FRP wraps. Field applications cover a diverse range of structures undercorrosive and cold climatic conditions.

2.3 Teaching ActivitiesOver 250 researchers are involved in ISIS Canada research activities. A substantialcommitment is made to preparing students to enter a highly specialized workforce inCanadas knowledge-based economy. Feedback from previous students who are nowemployed in the field of their choice, as well as from employers who invest substantialresources in seeking out potential employees, indicates that through the participatinguniversities, ISIS Canada is providing an enriched multidisciplinary, learning environment.Field demonstration projects across the country involve on-site installations that provide aunique experience for students to work with industry partners, and gain hands-onmultidisciplinary training.

In an effort to give design and construction engineers hands-on experience with ISIStechnologies in a setting conducive to questions and discussion, workshops are conductedacross the country. The ISIS network funds, coordinates and organizes the sessions, often

with support from industry partners who may also participate as guest speakers. This

manual, and its counterparts, serve as the technical base for these technology transfersessions.


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2.4


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USING THIS MANUAL

3.1

3.1 General RequirementsThe objective of this manual is to provide designers with guidelines and design equationsthat can be used for the design of FRP-reinforced concrete structures. This document is notpart of a national or international code, but is mainly based on experimental results of

research carried out in Canadian and other international university laboratories andinstitutions, and verified through field demonstration projects on functional structures.

The suggested design methodologies of this manual have, for the most part, been validatedby the research and testing carried out to date. A comparison of results of tests performedaround the world and published in scientific papers was performed. The comparison resultshave been used to validate the proposed equations. The proposed design equations arerepresentative of the tested models and are conservative when compared to available results.Since each reinforcing project is unique in its construction, loading history, andrequirements, no generalizations should be allowed in the design process.

Users of this manual should be aware that there remain many topics that are currently being

investigated by ISIS researchers, such as the durability of FRP materials, influence of on-siteconditions on material properties, anchoring methods, etc. Therefore, this manual is notexhaustive and should be used with caution.

3.2 Drawings and Related DocumentsThe engineer must prepare the various drawings and technical documents required forreinforced concrete structures using FRPs. These documents must identify all therequirements of existing standards (National Building Code, CSA-A23.3 Standard, CSA-S6Standard etc.), as well as the following additional information related to the FRP systems:

Identification of the FRP to be used.

Required FRP mechanical properties. Mechanical properties of the existing materials.

Summary of the considered design loads, allowable stresses, etc.

Quality control, supervision and field testing.

Load testing when required.

3.3 Code ReferencesACI Standards:

ACI-318-99, Building Code Requirements for Structural Concrete

ACI-421 (2000), Design of Reinforced Concrete Slabs

ACI-440H, Provisional Design Recommendations for Concrete Reinforced with

FRP Bars (Draft Version 2000) ACI-440K, Standard Test Method for FRP Rod and Sheet (Draft Version 1999)

ACI-435 (2000), A General Approach to Calculation of Displacements of ConcreteStructures


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3.2

ASTM Standards:

C234-86, Standard Test Method for Comparing Concretes on the Basis of the BondDeveloped with Reinforcing Steel

D792-86, Standard Test Methods for Density and Specific Gravity (RelativeDensity) of Plastics by Displacement

D696-91, Standard Test Method for Coefficient of Linear Thermal Expansion ofPlastics Between -30C and 30C

D638-86, Standard Test Method for Tensile Properties of Plastics

CSA Standards:

A23.3-94, Design of Concrete Structures

S806-00, Design and Construction of Building Components with Fibre ReinforcedPolymers (Draft Version 2000)

S6, Canadian Highway Bridge Design Code (CHBDC), 2000

National Research Council of Canada:

National Building Code of Canada, 1995

Other:

CEB-FIP Model Code (1990), Model Code for Concrete Structures, ThomasTelford, London, 1993


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FRP REINFORCING MATERIALS

4.1

4.1 Definitionsffrpu tensile strength of FRP, MPaF factor used for adjustment of FRP material resistance factor, to account for the ratio

of sustained to live load

R ratio of sustained to live loadfrpL longitudinal thermal expansion coefficient of FRP

frpT transverse thermal expansion coefficient of FRP

4.2 GeneralFRPs have been used for decades in the aeronautical, aerospace, automotive and other fields.

Their use in civil engineering works dates back to the 1950s when GFRP bars were firstinvestigated for structural use. However, it was not until the 1970s that FRP was finallyconsidered for structural engineering applications, and its superior performance over epoxy-coated steel recognized. The first applications of glass fibre FRP were not successful due toits poor performance within thermosetting resins cured at high moulding pressures (Parkyn

1970).

Figure 4.1 Available shapes of FRP products

Since their early application, many FRP materials with different types of fibres have been

developed. The fibres include aramid, polyvinyl, carbon and improved glass fibres. FRPproducts are manufactured in many different forms such as bars, fabric, 2D grids, 3D gridsor standard structural shapes, as shown in Figure 4.1. In this Section, the two majorcomponents of FRP materials, namely the fibres and the matrices (or resins), and theirproperties, as well as the mechanical properties of the final product, i.e. the FRP materials,are discussed.


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4.2

4.3 FRP ConstituentsFRP products are composite materials consisting of a matrix (resin) and reinforcing fibres.

As shown in Figure 4.2, the fibres are stronger than the matrix. In order to provide thereinforcing function, the fibre volume fraction should be more than 10 percent (ACI 1995).

The mechanical properties of the final FRP product depend on the fibre quality, orientation,shape, volumetric ratio, adhesion to the matrix, and on the manufacturing process. The latter

is an important consideration because simply mixing superior fibres and matrix does notguarantee a quality product. Accordingly, in FRP products with nominally the same fibres,matrix and fibre volume ratio can differ significantly in their final properties.

Figure 4.2 Stress-strain relationships for fibrous reinforcement and matrix

4.3.1 FibresFibres used for manufacturing composite materials must have high strength and stiffness,toughness, durability and preferably low cost. The performance of fibres is affected by theirlength, cross-sectional shape and chemical composition. Fibres are available in differentcross-sectional shapes and sizes. The most commonly used fibres for FRPs are carbon, glass,and aramid. Typical mechanical properties of these fibres can be found in Table 4.1. The

coefficient of thermal expansion of fibres in the longitudinal direction is denoted as FL, and

in the radial direction as FT.

stress[MPa]

strain

FRP

fibres

matrix

1800-4900

0.4-4.8 % >10 %

600-3000

34-130


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FRP Reinforcing Materials

4.3

Table 4.Table 4.Table 4.Table 4.1111 ---- Typical Mechanical Properties of FibresTypical Mechanical Properties of FibresTypical Mechanical Properties of FibresTypical Mechanical Properties of Fibres

FIBRE TYPEFIBRE TYPEFIBRE TYPEFIBRE TYPETensile StrengthTensile StrengthTensile StrengthTensile Strength

[MPa][MPa][MPa][MPa]Modulus of ElastiModulus of ElastiModulus of ElastiModulus of Elasticitycitycitycity

[GPa][GPa][GPa][GPa]ElongationElongationElongationElongation

[%][%][%][%]Coefficient of ThermalCoefficient of ThermalCoefficient of ThermalCoefficient of Thermal

Expansion [x10Expansion [x10Expansion [x10Expansion [x10----6666]]]]PoissonsPoissonsPoissonsPoissons

RatioRatioRatioRatio

CARBONCARBONCARBONCARBON

HighStrength 3500 200-240 1.3-1.8

PAN HighModulus

2500-4000 350-650 0.4-0.8

(-1.2) to (-0.1)(frpL)

7 to 12 (frpT)-0.2

Ordinary 780-1000 38-40 2.1-2.5

PitchHighModulus

3000-3500 400-800 0.4-1.5

(-1.6) to (-0.9)(frpL)

N/A

ARAMIDARAMIDARAMIDARAMIDKevlar 29 3620 82.7 4.4 N/A

Kevlar 49 2800 130 2.3-2.0 (frpL),59 (frpT)

Kevlar 129 4210 (est.) 110 (est.) -- N/A

Kevlar 149 3450 172-179 1.9 N/A

Twaron 2800 130 2.3(-2.0) (frpL),

59 (frpT)

Technora 3500 74 4.6 N/A

0.35

GLASSGLASSGLASSGLASSE-Glass 3500-3600 74-75 4.8 5.0 0.2

S-Glass 4900 87 5.6 2.9 0.22

Alkali ResistantGlass

1800-3500 70-76 2.0-3.0 N/A N/A

Table 4.2 (JSCE 1993, Banthia and MacDonald 1996) gives the performance of fibres indamaging environments, such as acids (hydrochloric acid, sulphuric acid, and nitric acid),alkalis (sodium hydroxide and brine) and organic solutions (acetone, benzene, and gasoline).Carbon fibres were found to have the best performance. More information on the durabilityof composites can be found in Benmokrane and Rahman (1998).

Table 4.Table 4.Table 4.Table 4.2222 ---- Chemical Resistance of Fibres (JSCE 1993, Banthia and McDonald 1996)Chemical Resistance of Fibres (JSCE 1993, Banthia and McDonald 1996)Chemical Resistance of Fibres (JSCE 1993, Banthia and McDonald 1996)Chemical Resistance of Fibres (JSCE 1993, Banthia and McDonald 1996)

FIBRE TYPEFIBRE TYPEFIBRE TYPEFIBRE TYPE Acid ResistanceAcid ResistanceAcid ResistanceAcid Resistance Alkali RAlkali RAlkali RAlkali Resistanceesistanceesistanceesistance Organic Solvent ResistanceOrganic Solvent ResistanceOrganic Solvent ResistanceOrganic Solvent Resistance

CARBONCARBONCARBONCARBON

High Strength Good Excellent ExcellentPAN

High Modulus Excellent Excellent Excellent

Ordinary Excellent Excellent ExcellentPitch

High Modulus Excellent Excellent Excellent

ARAMIDARAMIDARAMIDARAMID

Kevlar 49 Poor Good Excellent

Technora Good Good Good

GLASSGLASSGLASSGLASS

E-Glass Poor Fair Excellent

S-Glass Good Poor N/A

Alkali Resistant Glass Good Good N/A

OTHERSOTHERSOTHERSOTHERS

EC-Polyethylene Excellent Excellent Excellent

Polyvinyl Alcohol Fibre Good Good Good

Steel Fibre PoorExcellent to Sodium

Poor to BrineExcellent


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4.4

4.3.2 ResinsA very important issue in the manufacture of composites is the selection of the propermatrix because the physical and thermal properties of the matrix significantly affect the finalmechanical properties as well as the manufacturing process. In order to be able to exploit thefull strength of the fibres, the matrix should be able to develop a higher ultimate strain thanthe fibres (Phillips 1989). The matrix not only coats the fibres and protects them from

mechanical abrasion, but also transfers stresses between the fibres. Other very importantroles of the matrix are transfer of inter-laminar and in-plane shear in the composite, andprovision of lateral support to fibres against buckling when subjected to compressive loads(ACI 1995). There are two types of polymeric matrices widely used for FRP composites;namely, thermosetting and thermoplastic.

Thermosetting polymers are used more often than thermoplastic. They are low molecular-weight liquids with very low viscosity (ACI 1995), and their molecules are joined together bychemical cross-links. Hence, they form a rigid three-dimensional structure that once set,cannot be reshaped by applying heat or pressure. Thermosetting polymers are processed in aliquid state to obtain good wet-out of fibres. Some commonly used thermosetting polymersare polyesters, vinyl esters and epoxies. These materials have good thermal stability and

chemical resistance and undergo low creep and stress relaxation. However, these polymershave relatively low strain to failure, resulting in low impact strength. Two majordisadvantages are their short shelf life and long manufacturing time. Mechanical propertiesof some thermoset resins are provided in Table 4.3.

Table 4.Table 4.Table 4.Table 4.3333 Typical Properties of Thermosetting ResinsTypical Properties of Thermosetting ResinsTypical Properties of Thermosetting ResinsTypical Properties of Thermosetting Resins

ResinResinResinResin Specific GravitySpecific GravitySpecific GravitySpecific Gravity Tensile Strength [MPa]Tensile Strength [MPa]Tensile Strength [MPa]Tensile Strength [MPa] Tensile Modulus [GPa]Tensile Modulus [GPa]Tensile Modulus [GPa]Tensile Modulus [GPa] Cure Shrinkage [%]Cure Shrinkage [%]Cure Shrinkage [%]Cure Shrinkage [%]

Epoxy 1.20-1.30 55.00-130.00 2.75-4.10 1.00-5.00

Polyester 1.10-1.40 34.50-103.50 2.10-3.45 5.00-12.00

Vinyl Ester 1.12-1.32 73.00-81.00 3.00-3.35 5.40-10.30

Thermoplastic matrix polymers are made from molecules in a linear structural form. Theseare held in place by weak secondary bonds, which can be destroyed by heat or pressure.

After cooling, these matrices gain a solid shape. Although it can degrade their mechanicalproperties, thermoplastic polymers can be reshaped by heating as many times as necessary.

4.4 FRP Reinforcing Products and Material PropertiesFRP reinforcing bars are manufactured from continuous fibres (such as carbon, glass, andaramid) embedded in matrices (thermosetting or thermoplastic). Similar to steelreinforcement, FRP bars are produced in different diameters, depending on themanufacturing process. The surface of the rods can be spiral, straight, sanded-straight,sanded-braided, and deformed. The bond of these bars with concrete is equal to, or betterthan, the bond of steel bars. The mechanical properties of some commercially available FRP

reinforcing bars are given in Table 4.4 and durability aspects are discussed in Section 4.5.Appendix A contains addresses of the manufacturers.


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4.5

Table 4.4Table 4.4Table 4.4Table 4.4 Typical Mechanical Properties of FRP Reinforcing BarsTypical Mechanical Properties of FRP Reinforcing BarsTypical Mechanical Properties of FRP Reinforcing BarsTypical Mechanical Properties of FRP Reinforcing Bars

Trade NameTrade NameTrade NameTrade Name Tensile Strength [MPa]Tensile Strength [MPa]Tensile Strength [MPa]Tensile Strength [MPa] Modulus of Elasticity [GPa]Modulus of Elasticity [GPa]Modulus of Elasticity [GPa]Modulus of Elasticity [GPa] Ultimate TensiUltimate TensiUltimate TensiUltimate Tensile Strainle Strainle Strainle Strain

CARBON FIBRECARBON FIBRECARBON FIBRECARBON FIBRE

Leadline 2250 147.0 0.015

ISOROD 1596 111.1 0.023

NEFMAC 1200 100.0 0.012

GLASS FIBREGLASS FIBREGLASS FIBREGLASS FIBRE

ISOROD 690 42.0 0.018

C-Bar 770 37.0 0.021

NEFMAC 600 30.0 0.020

4.4.1 Manufacturing ProcessThere are three common manufacturing processes for FRP materials: pultrusion, braiding,and filament winding.

Pultrusion is a common technique for manufacturing continuous lengths of FRP bars thatare of constant or nearly constant profile. A schematic representation of this technique isshown in Figure 4.3. Continuous strands of reinforcing material are drawn from creels,through a resin tank, where they are saturated with resin, and then through a number of

wiper rings into the mouth of a heated die. The speed of pulling through the die ispredetermined by the curing time needed. To ensure good bond with concrete, the surfaceof the bars is usually braided or sand coated.

Figure 4.3 Pultrusion process

Braiding is a term used for interlocking two or more yarns to form an integrated structure.Filament winding is a process whereby continuous fibres are impregnated with matrix resinand wrapped around a mandrel. During the latter process, the thickness, wind angle, andfibre volume fraction are controlled. The final product is then cured using heat lamps. Themost common products manufactured using this process are pipes, tubes, and storage tanks.


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4.6

4.4.2 Coefficient of Thermal Expansion of FRPThermal properties of fibres are substantially different in the longitudinal and transversedirections, as shown in Table 4.5. Therefore, FRP reinforcing bars manufactured from thesefibres have different thermal expansion in these two directions.

Thermal characteristics vary between products, depending on the fibre and matrix type andthe fibre volume ratio. CFRP has a coefficient of thermal expansion in the longitudinaldirection close to zero (Erki and Rizkalla 1993, Sayed and Shrive 1998). Aramid fibre-reinforced polymer (AFRP) has a negative coefficient of longitudinal thermal expansion,indicating that AFRP contracts with increased temperature and expands with decreasedtemperature. GFRP has a longitudinal coefficient of thermal expansion comparable toconcrete; however, the transverse coefficient is more than five times greater (Challal andBenmokrane 1993). Coefficients of thermal expansion for some FRP reinforcing bars areshown in Table 4.5 (ACI 2000).

Table 4.5Table 4.5Table 4.5Table 4.5 Typical Coefficients of Thermal Expansion for FRP Reinforcing BarsTypical Coefficients of Thermal Expansion for FRP Reinforcing BarsTypical Coefficients of Thermal Expansion for FRP Reinforcing BarsTypical Coefficients of Thermal Expansion for FRP Reinforcing Bars1111

Coefficient of Thermal Expansion (x 10Coefficient of Thermal Expansion (x 10Coefficient of Thermal Expansion (x 10Coefficient of Thermal Expansion (x 10 ----6666/C)/C)/C)/C)

DirectionDirectionDirectionDirection SteelSteelSteelSteel GFRPGFRPGFRPGFRP CCCCFRPFRPFRPFRP AFRPAFRPAFRPAFRP

Longitudinal 11.7 6 to 10 -1 to 0 -6 to 2

Transverse 11.7 21 to 23 22 to 23 60 to 80

4.4.3 Effect of High TemperatureHigh temperatures may have a negative effect on the performance of FRP. Therefore,special precaution should be taken when FRP is used for structures where fire resistance is asignificant design factor. Even though FRP cannot burn when embedded in concrete, due toa lack of oxygen, the epoxy will soften. The temperature at which this occurs is referred to as

the glass transition temperature, Tg. The value of the glass transition temperature is afunction of resin type and generally reaches values of 150C (300F). At this temperature,both the flexural and bond strength of FRP will be affected. A limited number ofexperiments are reported in the literature to date. According to Katz et al. (1998 and 1999),bond strength of FRP can be reduced up to 40 percent at 100C (210F) and up to 90percent at 200C (390F). For GFRP, CFRP and AFRP fibres these temperatures are 980C(1800F), 1650C (3000F), and 175C (350F), respectively (ACI 2000).

At temperatures above 100C, FRPs may lose some of the resin binder. Sayed-Ahmed andShrive (1999) note that after 24 hours at 200C and 300C, the surface of Leadline hadbecome darker, indicating some resin loss. Twenty-four hours of exposure at 400C causedsome of the fibres on the surface to become loose. Exposure to 500C caused evaporationof the resin mainly within the first hour of exposure, reducing the tendon to a bundle of

loose fibres. The effect of temperature on the strength of Leadline can be clearly seen inFigure 4.4.

1 Typical values for fibre volume fraction ranging from 0.5 to 0.7.


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4.7

Figure 4.4 Effect of temperature on strength of Leadline (Sayed-Ahmed and Shrive 1999)

4.4.4 Bond Properties of FRP Reinforcing BarsBond properties of FRP bars depend on the surface preparation of the bar, which may besand coated, ribbed, helically wrapped, or braided. Mechanical properties of the bar, as wellas environmental conditions, influence bond of FRP bars (Nanni et al. 1997).

Friction, adhesion, and mechanical interlock transfer bond forces to concrete. Unlike forsteel-reinforced concrete, the compressive strength of concrete has no influence on the bondof FRP bars (Benmokrane et al. 1996). Detailed information regarding the developmentlength is presented in Section 8.

4.4.5 Fatigue of FRP Reinforcing BarsTensile fatigue of FRP reinforcing bars has not yet been thoroughly investigated. At present,there is no universally-accepted testing technique for FRP products; hence, each test resultmust be accompanied by a description of the testing technique used.

Tanigaki et al. (1989) reported tests of AFRP bar FiBRA, which were performed as partialpulsating tensile fatigue tests. The lower limit of the stress was equal to 50 percent of theactual tensile strength and the upper limit was varied. Table 4.6 contains results from thistest, which was performed at room temperature. The typical tensile strength of this bar is1255 MPa and, if the upper limit does not exceed 80 percent of the ultimate strength,rupture does not occur even under two million cycles. Refer to Table 4.6.

Table 4.6Table 4.6Table 4.6Table 4.6 ---- Tensile Fatigue Strength Results for FiBRA (fTensile Fatigue Strength Results for FiBRA (fTensile Fatigue Strength Results for FiBRA (fTensile Fatigue Strength Results for FiBRA (ffrpufrpufrpufrpu=1255 MPa, Tanigaki et al.1989)=1255 MPa, Tanigaki et al.1989)=1255 MPa, Tanigaki et al.1989)=1255 MPa, Tanigaki et al.1989)Lower LimitLower LimitLower LimitLower Limit Upper LimitUpper LimitUpper LimitUpper Limit

TestTestTestTestLoad [kN] Stress [MPa] Load [kN] Stress [MPa]

Stress Range [MPa]Stress Range [MPa]Stress Range [MPa]Stress Range [MPa]Cycles toCycles toCycles toCycles to

Rupture x 10Rupture x 10Rupture x 10Rupture x 103333

1 32.26 645.3 46.97 939.5 294.2 >2090

2 32.26 645.3 42.52 990.5 345.2 >3577

3 32.26 645.3 50.99 1019.9 374.6 >2063

4 32.26 645.3 54.43 1088.5 443.3 305


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4.8

CFRP has excellent resistance to fatigue. For 2 x 106 cycles, Leadline (Mitsubishi ChemicalCorporation) has an endurance limit of 1100 MPa at a stress ratio of 0.1. Yagi et al. (1997)tested pultruded CFRP at a stress ratio of 0.1, finding an endurance limit of 1400 MPa forone million cycles and 1200 MPa for ten million cycles.

4.4.6 Creep and Relaxation of FRP Reinforcing BarsThe creep behaviour of most FRP materials is characterised by an initial elastic response,followed by non-linear creep behaviour towards failure. When FRP materials are subjectedto a constant stress, they can fail suddenly. This phenomenon is referred to as creep rupture.

The larger the ratio of sustained load stresses to live load stresses, the smaller the enduranceof FRP. Creep rupture is also affected by ultraviolet radiation, high temperature, alkalinity,and weathering.

CFRP reinforcing bars are least susceptible to creep rupture, followed by AFRP, and then byGFRP which has the highest risk of failure due to creep rupture. To avoid creep rupture, thematerial resistance factors, discussed in Section 5, have been adjusted by a factor F accordingto CHBDC recommendations. Values for the factor F, accounting for the ratio of sustained

to live load stresses, R, are shown in Table 4.7. The value of R=2.0 was selected in thisdocument as the basis for reducing the material resistance factors for FRP reinforcing bars.

Table 4.7Table 4.7Table 4.7Table 4.7 Values of Factor FValues of Factor FValues of Factor FValues of Factor FRRRR

FRP TypeFRP TypeFRP TypeFRP Type0.50.50.50.5 1.01.01.01.0 2.02.02.02.0

AFRP 1.0 0.6 0.5

CFRP 1.0 0.9 0.9

GFRP 1.0 0.9 0.8

4.5 Durability of FRP Reinforcing BarsOne of the main reasons for considering FRP bars for concrete reinforcement is that steelbars can corrode in concrete subjected to harsh environments, resulting in a loss of strengthand structural integrity (ACI 2000). Concrete exposed to chlorides through marine or de-icing salts is particularly prone to corrosion of reinforcing steel. Concrete is highly alkaline,having a pH of about 12.5 to 13.5, and the alkalinity decreases with carbonation(Coomarasamy and Goodman 1997). Durability tests are conducted to determine thestrength and stiffness reduction due to natural aging of FRP bars under serviceenvironments during 50 to 100 years of service life. Many researchers are establishing thesereduction factors. Additional work is being conducted to establish calibration factors basedon field results.

Simple extrapolation of results from weathering exposure programs, although extremely

valuable, is not sufficient to support the rapid increase in the use of FRP reinforcement.Some form of an accelerated aging test procedure and predictive method is needed in orderto provide appropriate long-term strength estimates. The designer is referred to existingliterature for information on the conditioning environment for accelerated testing(Coomarasamy and Goodman 1997, Porter et al. 1997, and Porter and Barnes 1998,Benmokrane et al. 1998).


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4.9

Research on the effects of temperature on the durability of FRP bars in a concrete alkalineenvironment indicates that an acceleration factor for each temperature difference can bedefined by using Arrhenius laws. These factors differ for each product, depending on thetype of fibre, type of resin, and bar size. In addition, the factors are affected by theenvironmental condition, such as surrounding solution media, temperature, pH, moisture,and freeze-thaw conditions (Gerritse 1992, Coomarasamy and Goodman 1997, Porter et al.

1997, and Porter and Barnes 1998).

In another set of tests (Coomarasamy and Goodman 1997), the mass uptake results andmorphological studies on samples indicated a similar pattern qualitatively and, therefore, thesimple test method could be used as a screening procedure to eliminate poor qualityproducts without conducting extensive testing on them. The results of the mass uptakeshow an average increase of 0.6 percent after seven weeks for samples that retained 75percent of their structural integrity versus up to 2.4 percent for samples that lost theirstructural integrity.

In another set of tests, an increase in average moisture uptake of the GFRP samples made oflow-viscosity urethane-modified vinyl ester, was measured for a year under tap water, salt

solutions, and alkaline solutions. Maximum moisture uptake was observed to be under 0.6percent at room temperature. For tap and salt water immersion, moisture uptake was under0.3 percent. Alkaline conditioning produced about twice the moisture absorption rate inGFRP as compared to tap water and salt solution conditioning. This is an indication of therate and magnitude of strength and stiffness degradation in GFRP bars caused by an alkalineenvironment compared to plain water and salt solution (Vijay et al. 1998).

With regard to the durability characteristics of FRP bars, one is referred to the provisionalstandard test methods (Benmokrane et al. 1998). The designer should always consult withthe bar manufacturer before finalizing the design.

4.6 Commercially Available Reinforcing BarsThis Section contains design information on the types of commercial products available.Mechanical and geometric properties are included. Products are grouped based on fibre typeand are listed in alphabetical order. The contact address for each product is listed in

Appendix A.

4.6.1 Glass Fibre Reinforced Polymer Products

C-BAR Reinforcing Rod - C-BARTM reinforcing bars are provided in four different fibretypes: E-glass, carbon, aramid, and hybrid carbon and E-glass. Only the E-glass version ofC-BAR is included in this manual, refer to Figure 4.5 and Tables 4.8 and 4.9.


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4.10

Figure 4.5 C-BAR

Table 4.8Table 4.8Table 4.8Table 4.8 Chemical Composition (weight percentage) of CChemical Composition (weight percentage) of CChemical Composition (weight percentage) of CChemical Composition (weight percentage) of C----BAR Reinforcing RodBAR Reinforcing RodBAR Reinforcing RodBAR Reinforcing Rod(Marshall Industries Composites Inc.)(Marshall Industries Composites Inc.)(Marshall Industries Composites Inc.)(Marshall Industries Composites Inc.)

MATERIAL TYPEMATERIAL TYPEMATERIAL TYPEMATERIAL TYPE Grade AGrade AGrade AGrade A Grade BGrade BGrade BGrade B Grade CGrade CGrade CGrade C

Reinforcing fibre 60 % 70 % 70 %

Urethane modified vinyl ester N/A 15 % N/A

Recycled P.E.T. 10 % 10 % 30 %

SMC with urethane modified vinyl ester 30 % N/A N/A

Ceramic reinforcement N/A 3.5 % N/A

Corrosion inhibitor N/A 1.5 % N/A

Table 4.9Table 4.9Table 4.9Table 4.9 PropertiesPropertiesPropertiesProperties of Cof Cof Cof C----BAR, Grade B/Type 1 (Marshall Industries Composites Inc.)BAR, Grade B/Type 1 (Marshall Industries Composites Inc.)BAR, Grade B/Type 1 (Marshall Industries Composites Inc.)BAR, Grade B/Type 1 (Marshall Industries Composites Inc.)

PROPERTIESPROPERTIESPROPERTIESPROPERTIES

Designation number #12 #15

Cross section barrel diameter [mm] 12 15

Area [mm2] 113 176

Weight [kg/m] 0.25 0.37

Water absorption [%] 0.25 (max) 0.25 (max)

Barcol hardness [min] 60 60

Average ultimate tensile strength [MPa] 770 746

Standard deviation [MPa] 19 22

Design ultimate tensile strength [MPa] 713 680

Modulus of elasticity [GPa] 42 42

Bond strength [MPa] 17 18

The E-glass bar, also referred to as Type 1 bar, is available in three grades, Grade A, GradeB, and Grade C, based on the type of deformations and surface characteristics. In addition,Grade C bar is available for non-concrete reinforcement.


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4.11

Hughes Brothers, Inc. - Hughes Brothers reinforcing bars Aslan 100 are manufacturedusing glass fibres. The manufacturer provided the following mechanical properties of theirproduct, as shown in Tables 4.10 and 4.11.

Table 4.10Table 4.10Table 4.10Table 4.10 Geometric/Mechanical Properties of Bars Manufactured by Hughes BrothersGeometric/Mechanical Properties of Bars Manufactured by Hughes BrothersGeometric/Mechanical Properties of Bars Manufactured by Hughes BrothersGeometric/Mechanical Properties of Bars Manufactured by Hughes Brothers

Bar DesignationBar DesignationBar DesignationBar Designation NomNomNomNominal Diameterinal Diameterinal Diameterinal Diameter AreaAreaAreaArea Tensile StrengthTensile StrengthTensile StrengthTensile StrengthTensile Modulus ofTensile Modulus ofTensile Modulus ofTensile Modulus of

ElasticityElasticityElasticityElasticity

SI US Customary [mm] [in.] [mm2] [in.2] [MPa] [ksi] [GPa] [ksi]

6 #2 6.35 0.250 38.84 0.054 825 130 40.8 5920

9 #3 9.53 0.375 84.52 0.131 760 110 40.8 5920

12 #4 12.70 0.500 150.32 0.233 690 110 40.8 5920

16 #5 15.88 0.625 220.64 0.342 655 95 40.8 5920

19 #6 19.05 0.750 308.39 0.478 620 95 40.8 5920

22 #7 22.23 0.875 389.67 0.604 586 95 40.8 5920

25 #8 25.40 1.000 562.58 0.872 550 85 40.8 5920

32 #10 31.75 1.250 830.32 1.287 517 75 40.8 5920

Table 4.11Table 4.11Table 4.11Table 4.11 Other Material Properties of Bars Manufactured by Hughes BrothersOther Material Properties of Bars Manufactured by Hughes BrothersOther Material Properties of Bars Manufactured by Hughes BrothersOther Material Properties of Bars Manufactured by Hughes Brothers

Coefficient of Thermal ExpansionCoefficient of Thermal ExpansionCoefficient of Thermal ExpansionCoefficient of Thermal Expansion Bond StressBond StressBond StressBond Stress

TransverseTransverseTransverseTransverse LongitudinalLongitudinalLongitudinalLongitudinalSpecific GravitySpecific GravitySpecific GravitySpecific Gravity Glass Fibre ContentGlass Fibre ContentGlass Fibre ContentGlass Fibre Content

[x10-6/oC] [x10-6/oF] [x10-6/oC] [x10-6/oF][MPa][MPa][MPa][MPa] [psi][psi][psi][psi]

2.0(per ASTM D792)

70%(by weight)

21-2311.7-12.8

6-10 3.3-5.6 11.6 1679

ISOROD - Manufactured by a patented process, the ISOROD bar is a high strengthcomposite bar specially designed for concrete reinforcement. Depending on the type ofapplication and the customer need, the best combination between glass, carbon or aramidfibre, and polyester, vinyl ester or epoxy resin is selected. Refer to Figure 4.6 and Tables 4.12and 4.13.

Figure 4.6 ISOROD


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4.12

Table 4.12Table 4.12Table 4.12Table 4.12 Mechanical/PhysMechanical/PhysMechanical/PhysMechanical/Physical Properties of Glassical Properties of Glassical Properties of Glassical Properties of Glass----Vinyl Ester or Polyester ISORODVinyl Ester or Polyester ISORODVinyl Ester or Polyester ISORODVinyl Ester or Polyester ISOROD

PropertyPropertyPropertyProperty SI UnitsSI UnitsSI UnitsSI Units Imperial UnitsImperial UnitsImperial UnitsImperial Units

Mass, ASTM D792-86 2.04 to 2.10 [g/cm3] 0.074 to 0.076 [lb/in.3]

Coefficient of thermal expansionCoefficient of thermal expansionCoefficient of thermal expansionCoefficient of thermal expansion

Longitudinal, ASTM D696-79

Transverse, ASTM D696-79

8.85 to 9.11 x 10-6/oC

16.92 to 21.19 x 10-6/oC

2.62 to 2.70 x 10-7/oF

5.00 to 6.27 x 10-7/oF

Poissons ratio 0.27 to 0.29 0.27 to 0.29

Tensile strength,ASTM D638-86

635 to 747 MPa 92 to 108 ksi

Modulus of elasticity in tension,ASTM D638-86

37 to 43 GPa 5.4 to 6.2 Msi

Ultimate strain in tension,ASTM D638-86

1.6 to 2.0 % 1.6 to 2.0 %

Compressive strength,ASTM D695-85

487 to 451 MPa 71 to 78 ksi

Modulus of elasticity incompression ,ASTM D695-85

41 to 45 GPa 5.9 to 6.5 Msi

Ultimate strain in compression,ASTM D4476-85 1.1 to 1.5 % 1.1 to 1.5 %

Flexural strength,ASTM D4476-85

1100 to 1500 MPa 160 to 217 ksi

Flexural modulus of elasticity,ASTM D4476-85

58 to 68 GPa 8.4 to 9.8 Msi

Ultimate strain in flexure,ASTM D4476-85

1.7 to 2.3 % 1.7 to 2.3 %

Shear strength 163 to 206 MPa 24 to 30 ksi

Bond stress in normal concrete,f c = 30 MPa,

ASTM C234-8611 to 15 MPa 1.6 to 2.2 ksi

Bond stress in high strengthconcrete, f c = 80 MPa,ASTM C234-86

8 to 15 MPa 1.2 to 2.2 ksi

Bond stress in cement grout,f c = 40 MPa,ASTM C234-86

8 to 15 MPa 1.2 to 2.2 ksi

TableTableTableTable 4.134.134.134.13 Geometric Properties of ISORODGeometric Properties of ISORODGeometric Properties of ISORODGeometric Properties of ISOROD

ISORODISORODISORODISOROD GlassGlassGlassGlass----Vinyl EsterVinyl EsterVinyl EsterVinyl Ester

Size Area Nominal Diameter Mass WeightDesignation

[mm] [in.] [mm2] [in.2] [mm] [in.] [kg/m] [lb/ft]

3/8 9.3 0.366 71 0.11 9.5 3/8 0.142 0.100

1/2 12.3 0.484 129 0.20 12.7 1/2 0.266 0.179

5/8 15.6 0.612 200 0.31 15.9 5/8 0.398 0.2523/4 18.7 0.737 284 0.44 19.1 3/4 0.602 0.404

1 24.9 0.980 507 0.79 25.4 1 1.044 0.700


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4.13

NEFMAC Glass Reinforcing Grid - NEFMAC is a non-corrosive, lightweight materialmade of FRP that is formed in a two- or three-dimensional grid shape by using impregnatedhigh performance continuous fibres such as carbon, glass, and aramid fibre with resin. Referto Figure 4.7 and Table 4.14.

Figure 4.7 NEFMAC

Table 4.14Table 4.14Table 4.14Table 4.14 Material Properties of NEFMAC (Glass)Material Properties of NEFMAC (Glass)Material Properties of NEFMAC (Glass)Material Properties of NEFMAC (Glass)

GLASS FIBREGLASS FIBREGLASS FIBREGLASS FIBRE

Bar No.Bar No.Bar No.Bar No. Area [mmArea [mmArea [mmArea [mm2222]]]]Max. Tensile LoadMax. Tensile LoadMax. Tensile LoadMax. Tensile Load

[kN][kN][kN][kN]Tensile StrengthTensile StrengthTensile StrengthTensile Strength

[MPa][MPa][MPa][MPa]Modulus of ElasticityModulus of ElasticityModulus of ElasticityModulus of Elasticity

[GPa][GPa][GPa][GPa]Mass [g/m]Mass [g/m]Mass [g/m]Mass [g/m]

G2 4.4 2.6 7.5

G3 8.7 5.2 15

G4 13.1 7.8 22

G6 35.0 21 60

G10 78.7 47 130

G13 131.0 78 220

G16 201.0 120 342

G19 297.0 177

600 30

510


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4.14

ROTAFLEX Rod - ROTAFLEX ROD is composed of glass fibre coupled with epoxyresin. The fibres are in a uni-directional orientation. The composition is 80 percent by weightof glass and 20 percent of epoxy resin. Refer to Figure 4.8 and Table 4.15.

Figure 4.8 ROTAFLEX

Table 4.15Table 4.15Table 4.15Table 4.15 Physical Properties of ROTAFLEXPhysical Properties of ROTAFLEXPhysical Properties of ROTAFLEXPhysical Properties of ROTAFLEX

Weight per metre 41 gm

Specific gravity 2.9 gm/cm3

Tensile strength 1800 MPa (provisional)

Modulus of elasticity 56 GPa

Water absorption < 0.1%

4.6.2 Carbon Fibre Reinforced Polymer Products

LEADLINETM - LEADLINETM is made by the pultrusion process to produce an FRP rodwith linearly-oriented carbon fibres that have a higher strength and better properties thantwisted carbon fibre cables of the same diameter. Refer to Figure 4.9 and Tables 4.16 and4.17.

Figure 4.9 LEADLINE


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4.15

Table 4.16Table 4.16Table 4.16Table 4.16 Geometric/Mechanical Properties of LEADLIGeometric/Mechanical Properties of LEADLIGeometric/Mechanical Properties of LEADLIGeometric/Mechanical Properties of LEADLINNNNEEEETMTMTMTM

Diameter [mm] Area [mm2] Tensile Strength [MPa]Modulus of Elasticity

[GPa]Mass [g/m]

RoundRoundRoundRound

5 19.6 2245 147 32

8 49.0 2265 147 80

12 113.1 2255 147 184

Indented spiralIndented spiralIndented spiralIndented spiral

5 17.8 2247 147 30

8 46.1 2255 147 77

12 108.6 2255 147 177

Indented concentricIndented concentricIndented concentricIndented concentric

5 18.1 2265 147 30

8 46.5 2258 147 76

12 109.3 2250 147 178

Table 4.17Table 4.17Table 4.17Table 4.17 Physical Properties of LEADLINEPhysical Properties of LEADLINEPhysical Properties of LEADLINEPhysical Properties of LEADLINETMTMTMTM

Diameter [mm] 8

Matrix Epoxy resin

Fibre volume fraction 65

Tensile strength 2550

Modulus of elasticity 147

Elongation [%] 1.8

Unit weight [g/m] 77

Specific gravity 1.6

Relaxation ratio (at 20C) 2-3

Thermal expansion 0.7 x 10 6 / C

ISOROD Carbon-Vinyl Ester Reinforcing Bar - The tensile strength of 10 mm bar isgiven as 1596 MPa (231.5 ksi), and the modulus of elasticity 111.1 GPa (16.1 Msi). Refer to

Table 4.18 for geometric properties of ISOROD Carbon Vinyl Esters. Tables 4.19 and 4.20outline the properties for other comparable manufactured products.

Table 4.18Table 4.18Table 4.18Table 4.18 Geometric Properties of ISORODGeometric Properties of ISORODGeometric Properties of ISORODGeometric Properties of ISOROD CarbonCarbonCarbonCarbon Vinyl EsterVinyl EsterVinyl EsterVinyl Ester

Bar DesignationBar DesignationBar DesignationBar Designation AreaAreaAreaArea DiameterDiameterDiameterDiameter MassMassMassMass WWWWeighteighteighteight

SI US Customary [mm2] [in.2] [mm] [in.] [kg/m] [lbs/ft]

#10 #3 71 0.11 9.3 0.366 0.142 0.100

#13 #4 129 0.20 12.3 0.484 0.266 0.179

#16 #5 507 0.79 24.9 0.980 1.044 0.700


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4.16

NEFMAC Carbon Reinforcing Grid

S&P Laminates

Table 4.20Table 4.20Table 4.20Table 4.20 Properties of S&P LaminatesProperties of S&P LaminatesProperties of S&P LaminatesProperties of S&P LaminatesS&P laminates CFK 150/2000 S&P laminates CFK 200/2000

Modulusof Elasticity

Tensile Strengthat Break

Modulusof Elasticity

Tensile Strength at Break

>150 GPa >2400 MPa >200 GPa >2300 MPa

Width/Thickness[mm/mm]

Tensile Force at Elongation of0.6/0.8%

Width/Thickness[mm/mm]

Tensile Force at Elongation of0.6/0.8%

50/1.2 58/77 x 103 N

50/1.4 67/90 x 103 N 50/1.4 834/112 x 103 N

80/1.2 92/123 x 103 N

80/1.4 108/143 x 103 N 80/1.4 134/179 x 103 N

100/1.2 115/154 x 103 N

100/1.4 134/179 x 103 N 100/1.4 168/224 x 103 N

120/1.4 201/269 x 103 N

4.6.3 Aramid Fibre Reinforced Polymer Products

NEFMAC Aramid Reinforcing Grid

Table 4.21Table 4.21Table 4.21Table 4.21 Material Properties of NEFMAC (Aramid)Material Properties of NEFMAC (Aramid)Material Properties of NEFMAC (Aramid)Material Properties of NEFMAC (Aramid)ARAMID FIBRESARAMID FIBRESARAMID FIBRESARAMID FIBRES

Bar No. Area [mm2]Max. Tensile Load

[kN]Tensile Strength

[MPa]Modulus of

Elasticity [GPa]Mass [g/m]

A6 16.2 21 21

A10 36.2 47 46

A13 60.0 78 77

A16 92.3 120 118

A19 136.0 177

1300 54

174

4.6.4 Hybrid Fibre Reinforced Polymer Products

NEFMAC Hybrid (Glass and Carbon) Reinforcing Grid

Table 4.22Table 4.22Table 4.22Table 4.22 Typical Properties of NEFMAC Hybrid Reinforcing GridTypical Properties of NEFMAC Hybrid Reinforcing GridTypical Properties of NEFMAC Hybrid Reinforcing GridTypical Properties of NEFMAC Hybrid Reinforcing GridTensile strength 600 MPa

Modulus of elasticity 37 GPa

Table 4.19Table 4.19Table 4.19Table 4.19 Material Properties of NEFMACMaterial Properties of NEFMACMaterial Properties of NEFMACMaterial Properties of NEFMAC (Carbon)(Carbon)(Carbon)(Carbon)CARBON FIBRECARBON FIBRECARBON FIBRECARBON FIBRE

Bar No. Area [mm2]Maximum Tensile Load

[kN]Tensile Strength

[MPa]Modulus of Elasticity

[GPa]Mass [g/m]

C6 17.5 21 25

C10 39.2 47 56

C13 65.0 78 92

C16 100.0 120 142

C19 148.0 177 210

C22 195.0 234

1200 100

277


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THE DESIGN PROCESS

5.1

5.1 Definitionso modulus of elasticity of concrete, MPaf c compressive strength of concrete, MPafr modulus of rupture, MPa

k stress decay factorn curve fitting factorRn nominal resistanceSn nominal load effect

load factor

importance factor

c density of concrete, kg/m3

c strain in concrete

o strain in concrete at peak stress

resistance factor

modification factor for density of concrete

load combination factor

5.2 Limit States DesignCanadian codes are based on a unified limit state design philosophy. To reduce theprobability of failure of a structure, either its resistance (R) is underestimated, and/or theeffects of loads are overestimated. The general form can be written as:

Equation 5.1 nn SR

material resistance factorRn nominal resistance load factor (or performance factor)Sn nominal load effect

The material resistance factor, , is always less than unity, to reflect the uncertainties in

determining the nominal resistance, Rn. The load factor, , is usually greater than unity toreflect the uncertainties in determining the nominal load effect, Sn. Both the materialresistance factor and the load factor will be discussed in greater detail in the followingSections.

5.3 Load Factors and Loading Combinations for BuildingsThis Section will discuss load factors and loading combinations for design of concretemembers reinforced with FRP. Loads considered in the design process follow CSA A23.3-94and are denoted as follows:

D dead loadL live load

W wind loadT temperature variations, creep, shrinkage and differential settlementQ earthquake


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5.2

The effects of factored loads are considered in the design of a structure. Factored loads areobtained by multiplying the specified loads by load factors. The following factors areconsidered:

load combination factor

D dead load factor

L live load factor

W wind load factor

T temperature load factor

importance factor

5.3.1 Load Combinations

Load Combination Factor ()

For load types L, W and T, the magnitude of the load combination factor, , depends onthe number of load types (L, W, or T) acting simultaneously.

When only one load type is applied to the structure, = 1.00

When two of the loads are applied, = 0.70

When all three loads are applied simultaneously, = 0.60

The most unfavourable effect of load should be determined by considering each load type(L, W, T) alone with the importance factor of 1.00, or in combinations with the appropriateimportance factor given in Section 5.3.3.

Load Combinations not Including EarthquakeThe effect of load combinations, not including earthquake, should be taken according to thefollowing:

Equation 5.2

Load Combinations Including EarthquakeFor load combinations including earthquake, the factored load combinations will always

include 1.00D + (1.00E) and one of the following:

for storage and assembly occupancies, 1.00D + (1.00L + 1.00E); or

for all other occupancies, 1.00D + (0.50L + 1.00E)

RTT

WW

LL

DD


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The Design Process

5.3

5.3.2 Load FactorsThe load factors, , for dead load (D), live load (L), wind load (W), and temperature load

(T), respectively, are: D = 1.25, except when the dead load resists overturning, uplift, or

reversal of load effect, in which case, D = 0.85

L = 1.5

W= 1.5T = 1.25

5.3.3 Importance Factor

The importance factor, , should always be 1.0, unless it is proven that collapse of the

structure will not cause serious consequences, in which case is taken as 0.8.

5.3.4 Resistance FactorsThe material resistance factor for concrete is c = 0.65. The material resistance factor forFRP is based on variability of the material characteristics, the effect of sustained load and the

type of fibres.

5.4 Load Factors and Loading Combinations for BridgesThis Section denotes the load factors and load combinations to be used in bridge design, as

specified in the Canadian Highway Bridge Design Code. The following loads are considered:

A ice accretion loadD dead loadE loads due to earth pressure and hydrostatic pressure other than dead load;

surcharges shall be considered as earth pressure even when caused by other loadsF loads due to stream flow and ice pressureH collision loadK all strains, deformations, displacements and their effects, including the effects of

their restraint and those of friction or stiffness in bearings; strains and deformationinclude those due to temperature change and temperature differential, concreteshrinkage, differential shrinkage and creep, but not elastic strains

L live load, including dynamic allowance when applicableQ earthquake loadS load due to foundation deformation

V wind load on live loadW wind load on structure

Table 5.1Table 5.1Table 5.1Table 5.1 Resistance Factors for FRPResistance Factors for FRPResistance Factors for FRPResistance Factors for FRP

FRP TypeFRP TypeFRP TypeFRP Type frp

CFRP 0.8

AFRP 0.6

GFRP 0.4


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5.4

5.4.1 Load CombinationsAll combinations of factored loads specified in Table 5.2, using the dead load factor D, and

earth load factor E, as given in Table 5.3.

1 Use Table 5.3 for values ofDand E.2 For luminary sign, traffic signal supports, barriers and slender structure elements.

Table 5.2Table 5.2Table 5.2Table 5.2 Load Combinations for Bridges (Canadian Highway Bridge Design Code)Load Combinations for Bridges (Canadian Highway Bridge Design Code)Load Combinations for Bridges (Canadian Highway Bridge Design Code)Load Combinations for Bridges (Canadian Highway Bridge Design Code)

PermanentPermanentPermanentPermanentLoadsLoadsLoadsLoads1111

TransitorTransitorTransitorTransitory Loadsy Loadsy Loadsy LoadsExceptional LoadsExceptional LoadsExceptional LoadsExceptional Loads

(use one only)(use one only)(use one only)(use one only)

LoadsLoadsLoadsLoads DDDD EEEE LLLL KKKK WWWW VVVV SSSS QQQQ FFFF AAAA HHHH

FATIGUE LIMIT STATESFATIGUE LIMIT STATESFATIGUE LIMIT STATESFATIGUE LIMIT STATES

Combination 1 1.00 1.00 0.80 0 1.002 0 0 0 0 0 0

SERVICEABILITY LIMIT STATESSERVICEABILITY LIMIT STATESSERVICEABILITY LIMIT STATESSERVICEABILITY LIMIT STATES

Combination 1 1.00 1.00 0.75 0.80 0.702 0 1.00 0 0 0 0

ULT