Effect of Member Depth on Shear Strength of High-Strength Fiber-Reinforced Polymer–Reinforced Concrete Beams

Abstract

This paper examines the effect of depth on the shear strength and behavior of high-strength concrete beams reinforced with glass-fiber-reinforced polymer (GFRP) and carbon-fiber-reinforced polymer (CFRP) bars in the longitudinal direction only without stirrups. Three beams, for each reinforcement type, with depths approximately equal to 300, 450, and 600 mm were tested to determine their shear strength and behavior before and after cracking. The targeted concrete strength was 70 MPa. The tests were carried out using two-point monotonic loading. The test results are presented in terms of crack patterns, load-deflection behavior, and failure modes. It was observed that the shear strength decreased with the increase in the depth of the beams. These results were compared with Bažant size-effect law and a good agreement was observed. The test results were also compared with the predictions using the Canadian Standard Association (CSA) and American Concrete Institute (ACI) shear design equations. The predicted results using the CSA equation were in better agreement with the experimental results than those obtained using the ACI equation.