Effect of Longitudinal Reinforcement Ratio on Shear Capacity of Concrete Beams with GFRP Bars

This paper evaluates the shear capacity of concrete beams longitudinally reinforced with glass fiber-reinforced polymer (GFRP) bars. All beams were provided with steel stirrups as shear reinforcement within shear region with spacing, 150 mm. The effect of longitudinal reinforcement ratios, ρ f is discussed and compared with conventional beams reinforced with steel. The test results were compared with predictions recommended by ACI 440.1R-06 design guidelines and by other references. Other performance in terms of tensile strength and stresses in reinforcement bars was analyzed. Based on the findings of test results, it is shown that the shear resistance of GFRP RC beam is influenced by modulus elasticity of GFRP bars that resulted in low shear strength compared to conventional beams. Moreover, due to specific properties of GFRP materials, shear behavior of beams with GFRP bars is different to that of beams with steel. The current design guideline (ACI 440.1R-06) was found to be very conservative compared with experimental results.