Experimental investigation on the effect of longitudinal reinforcement on shear strength of fibre reinforced polymer reinforced concrete beams

The shear design equation of CSA S806-02 does not consider the effect of the axial stiffness of the reinforcing bars for beams with effective depth greater than 300 mm. This paper examines the shear strength of such beams without stirrups. A total of 16 beams reinforced with GFRP, CFRP, and steel bars were tested under four-point monotonic loading. The test results were analyzed and compared with the predictions of CSA S806-02 shear design equation. It was observed that the conservatism of CSA S806-02 prediction, for beams with effective depth greater than 300 mm, increased with the increase in the axial stiffness of the reinforcing bars. Based on the test results, a modification to the CSA S806-02 shear design equation is proposed. The proposed modification was found to be consistent for predicting the shear strength of beams with different axial stiffness of the reinforcing bars.