Shear strength of fibre-reinforced polymer reinforced concrete deep beams without web reinforcement

This paper describes an experimental investigation to evaluate the shear strength and behavior of concrete deep beams reinforced with fibre-reinforced polymer (FRP) bars. A total of ten full-scale reinforced concrete beams without web reinforcement were constructed and tested in four-point bending. The test variables were the reinforcement ratio and the modulus of elasticity of the longitudinal reinforcing bars as well as the shear span to depth ratio. The test beams included five beams reinforced with glass FRP bars and five beams reinforced with carbon FRP bars. The behavior of the deep beams is described in terms of load-deflection response, cracking patterns and modes of failure, strains in reinforcement and concrete, inclined cracking, and ultimate shear strengths. All ten beams showed significant reserve strength after the inclined cracking was fully developed. The test results also indicated that the ultimate shear strength of the tested beams considerably increased with the decrease of the shear span to depth ratio. In addition, the ultimate shear strengths of the tested beams were predicted using the shear design provisions recommended by the new version of the Canadian Standard CSA-S806-11 and compared with the experimental results, showing good agreement.