Shear strength model for fibre reinforced polymer shear reinforced concrete beams

In the present study, an integrated shear design method was developed to evaluate the shear strength of concrete beams with and without fibre reinforced polymer shear reinforcement. The contributions of fibre reinforced polymer steel re-bars, and concrete to shear strength were defined separately. The shear strength contribution of a concrete cross-section was defined by the strain-based shear strength model developed in the previous study. In the model, the shear strength of the concrete cross-section was evaluated based on the material failure criteria of the concrete subjected to the compressive normal stress and shear stress. In this study, the ratio of FRP effective strain to ultimate strain needed to evaluate the fibre reinforced polymer shear strength contribution was defined based on the existing test results. The proposed strength model was verified by comparing its prediction to prior test results. In the comparison, it was found that the proposed method accurately predicted the shear strengths of the test specimens for both FRP shear reinforced and unreinforced concrete beams.