Experimental Investigation of Glass Fiber-Reinforced Polymer-Reinforced Normal-Strength Concrete Beams

Results from an experimental program consisting of 10 large beams are presented herein that investigated the performance of the most current generation of bent glass fiber-reinforced polymer (GFRP) stirrups. In the experiments, strains greater than 1% were measured in the transverse reinforcement, which significantly exceeded the code-prescribed design values. No substantial difference in the shear strength was noted between beams reinforced with either sand-coated or milled-surface stirrups. Predictions of ultimate strength using CSA S806-12, CSA S6-06, and ACI 440.1R-06 were all found to be safe if the prescribed strain limits for FRP transverse reinforcement were used. Finally, it was shown that performance of the reinforcement at load levels close to service condition with respect to shear cracking was of critical importance, as evidenced by the observations that measured shear cracks were wider in some cases than flexure cracks.