Shear strength model for reinforced concrete beams with web reinforcement

Abstract

The modified compression field theory (MCFT), developed in the 1980s, is capable of predicting the shear behaviour of reinforced concrete (RC) and forms the basis of shear provisions in Canadian and American specifications for the design of concrete structures. In the MCFT method, shear is considered to be resisted by cracked concrete and web reinforcement. However, previous studies have shown that a significant portion of the shear is carried by the compression zone. This paper describes further studies on the MCFT to predict shear capacity while taking account of the contribution of concrete in compression. In the proposed model, the shear strength of RC beams is defined as the sum of contributions of concrete in the compression zone, cracked concrete below the neutral axis and shear reinforcement. The results predicted by the proposed model are compared with data from beam experiments in the literature. The shear strengths predicted by the proposed method are in good agreement with the test results, implying that the method can be used to predict shear capacity for RC beams.