Experimental and analytical study on shear behavior of strain-hardening cementitious composite beams reinforced with fiber-reinforced polymer bars

Application of fiber-reinforced polymer (FRP) reinforcement in concrete beams may cause large deflection and crack width, as well as low shear capacity and ductility due to relatively small stiffness of FRP materials. To avoid these unfavorable factors and evaluate the shear behavior of FRP-reinforced structural members, a high-performance strain-hardening cementitious composite (SHCC) is introduced to substitute conventional concrete in reinforced beams, and four-point bending test is conducted in this study. Six FRP-reinforced SHCC beams with different transverse reinforcement ratios and shear spans, as well as one concrete reference beam, were tested. According to the test results, the FRP-reinforced SHCC beam showed enhanced shear carrying capacity and superior ductility compared with the concrete beams. The shear span to effective depth ratio as well as the stirrup ratio has a great influence on the shear behavior of FRP-reinforced SHCC beams, including the failure mode, load-carrying capacity, crack propagation, and ductility. Finally, a simplified truss-strut model for predicting shear carrying capacity of steel or FRP-reinforced SHCC beams is proposed, and a good agreement is achieved with the experimental results.