SHEAR ANALYSIS OF DEEP FLEXURAL MEMBER BASED ON CRACK BAND THEORY

Previous research has shown that the current specifications and typical shear models were failed to reasonably consider the size effect on shear bearing capacity of deep flexural members. This paper proposes a reasonable shear model for deep flexural members by combining an energy loss equilibrium equation in fracture mechanics with the crack band theory based on the strut-and-tie model. 343 reinforced concrete deep flexural members were collected and were used to simplify the proposed shear model. To determine the rationality of a simplified shear model, its calculation results and the predicted results obtained from ACI 318-14, EC2, CSA A23.3-04 and GB50010-2010 were compared with the test results. The comparison results show that the shear bearing capacity of deep flexural members predicted by the simplified shear model based on crack band theory is better than those determined from others current specifications and from Tan-Cheng model, and that also in a better agreement with the test results. Owing to the specific force transfer mechanisms and the less effect of shear span to a depth ratio, it is also concluded that this proposed model can reasonably consider the size effect of large members, and can accurately predict the shear bearing capacity of reinforced concrete deep flexural members.