Design Codes

Since the mechanical properties of GFRP fiberglass rebar differ from those of steel, design engineers should consider recommendations made in published design and construction guides prior to using GFRP fiberglass rebar in their structures.

 

Several important differences between steel and GFRP fiberglass rebar should be considered prior to designing your concrete structures using fiberglass rebar:

  • Direct substitution of GFRP fiberglass rebar with steel rebar may not be possible in some cases
  • A lower modulus of elasticity and shear strength may impact the number of reinforcing bars required
  • GFRP fiberglass rebar has a limited maximum sustained shear stress.
  • Guaranteed design tensile strength of fiberglass rebar has to be de-rated in certain applications
  • Some types of GFRP fiberglass rebar are not suitable for certain pre-stressing or post-tensioning applications

There are extensive publications existing dealing with the design and usage of GFRP rebar. They include but are not limited to:

 

Canada

  • CAN/CSA-S6-06 (2006) Fibre Reinforced Structures, "Canadian Highway Bridge Design Code" Canadian Standards Association, pg.693-728
  • CAN/CSA-S806-02 (R2007) "Design and Construction of Building Components with Fibre-Reinforced Polymers" Canadian Standards Association

Through ISIS (Intelligent Sensing for Innovative Structures) Canada's group of researchers the following are available:

  • Manual No. 3 (Version 2) "Reinforcing Concrete Structures with Fibre Reinforced Polymers (FRPs)", Dr. Sami Rizkalla, Dr. Aftab Mufti
  • Manual No. 4 "Strengthening Reinforced Concrete Structures with Externally-Bonded Fibre Reinforced Polymers (FRPs)", Dr. Kenneth Neale
  • Manual No. 5 "Prestressing Concrete Structures with FRPs" Dr. Ivan Campbell

USA  

  • ACI 440.1R-06 (2006) "Report on Fiber Reinforced Poler (FRP) Reinforcement for Concrete Structures", ACI Committee 440, American Concrete Institute
  • ACI 440R-07 (2007) "Report on Fiber-Reinforced Polymer (FRP) Reinforcement for Concrete Structures" ACI Committee 440, American Concrete Institute
  • ACI 440.5-08 (2008) "Specification for Construction with Fiber-Reinforced Polymer Reinforcing Bar" ACI Committee 440, American Concrete Institute
  • ACI 440.6-08 (2008) "Specification for Carbon and Glass Fiber-Reinforced Polymer Bar Materials for Concrete Reinforcement," ACI Committee 440, American Concrete Institute
  • AASHTO GFRP-1 (2009) " AASHTO LRFD Bridge Design Guide Specifications for GFRP-Reinforced Concrete Bridge Decks and Traffic Railings", American Association of State Highway and Transportation Officials