Quantitative evaluation of two shear transfer mechanisms in earthquake resistant beam-column joints

It is a very important unresolved problem of how to figure out the contributions of two kinds of shear transfer mechanisms respectively, i.e. the strut mechanism and the truss mechanism, in RC beam column joints subjected to different levels of shear reversals. The main obstacle is to find out a rational method which can not only represent the behavior of joints but also have clear physical background. In this paper, a so called ‘simply supported beam column model’was proposed based on the serial test results. If the forces in the reinforcement and compressed concrete in beams and columns surrounding a joint were known, the contributions of such two mechanisms in shear transfer in the joint core could be determined respectively by using this model, while the upper and lower reinforcement in the beams may be symmetric or asymmetric. The predicted results have shown good agreement with the test results.