Shear Capacity of High-Strength Concrete Beams Reinforced with Fiber-Reinforced Polymer Bars

Abstract

This paper reports experimental data on the behavior and shear strength of high-strength concrete slender beams reinforced with fiber-reinforced polymer (FRP) bars. Shear tests were conducted on six large-scale reinforced concrete beams without stirrups using high-strength concrete (f' c = 65 MPa) along with three beams using normal-strength concrete (f' c = 35 MPa). The beams measured 3250 mm long, 250 mm wide, and 400 mm deep, and were tested in four-point bending. The test variables were strength of concrete, and the reinforcement ratio and modulus of elasticity of the longitudinal reinforcing bars. Carbon and glass FRP bars and conventional steel bars were used as longitudinal reinforcement in this investigation. The experimental shear strengths of the FRP-reinforced concrete beams were compared to theoretical predictions provided by ACI 440.1R-03 and the modified form of this method proposed by the authors. The test results indicated that the high-strength concrete beams exhibited slightly lower relative shear strength compared to normal-strength concrete beams. In addition, the ACI 440.1R-03 design method provided very conservative predictions whereas the proposed modified equation gave better results.