Effect of plastic rotation on the concrete contribution to shear strength of RC beams

This paper provides an analytical model to predict the concrete contribution to shear strength of reinforced concrete (RC) beams that fail in flexure. In the RC members subjected to cyclic loading, the stiffness and hysteretic energy dissipation decreases with diagonal web cracking in the plastic hinge region. The proposed method takes into account plastic rotation in the plastic hinge region by means of critical shear crack theory. To verify the concrete contribution to shear strength predicted by the proposed method, six normal- and high-strength RC beams having various shear span-to-effective depth ratios are tested under cyclic loading. The predictions by the proposed equation and various researchers' equations are compared to the test results. It is found that the proposed method is in good agreement with the test results.