Abstract
The behavior and shear strength of concrete slender beams reinforced with fiber-reinforced polymer (FRP) bars were investigated. A total of nine large-scale reinforced concrete beams without stirrups were constructed and tested up to failure. The beams measured 3250 mm long, 250 mm wide, and 400 mm deep and were tested in four-point bending. The test variables were the reinforcement ratio and the modulus of elasticity of the longitudinal reinforcing bars. The test beams included three beams reinforced with glass FRP bars, three beams reinforced with carbon FRP bars, and three control beams reinforced with conventional steel bars. The test results were compared with predictions provided by the different available codes, manuals, and design guidelines. The test results indicated that the relatively low modulus of elasticity of FRP bars resulted in reduced shear strength compared to the shear strength of the control beams reinforced with steel. In addition, the current ACI 440.1R design method provided very conservative predictions, particularly for beams reinforced with glass FRP bars. Based on the obtained experimental results, a proposed modification to the current ACI 440.1R design equation is presented and verified against test results of other researchers. [PUBLICATION ABSTRACT]