Shear capacity of diagonally reinforced coupling beams

This paper summarizes a theoretical model to predict the monotonic load–deformation behavior of diagonally reinforced coupling beams. The model assumes all load is resisted by diagonal tension and compression. The diagonal compression is carried by the diagonal reinforcement and the concrete core surrounded by the diagonal bars in that direction, while the diagonal tension is carried only by the diagonal reinforcement. Either rupture of the diagonal reinforcement or crushing of the concrete core defines the end point of the behavior (failure) of the coupling beam. The strain hardening of the reinforcing steel is considered in this study, which is an important source of strength at high deformation. The model is applied and compared to experimental tests that were conducted by several investigators (total of 13 specimens). The specimens vary in terms of dimensions, reinforcement and material properties. The model gave good results compared to the test results.