MODELING OF LOAD-RESISTANCE MECHANISMS OF REINFORCED CONCRETE KNEE JOINTS

Based on the previous test research findings, the load-resistance models for reinforced concrete knee joints were proposed. It is shown that the joint strength depends not only on shear resisting mechanism but also on moment resisting mechanism as well as anchorage mechanism of the joint. The mechanism in the opening direction differs from that in the closing direction. In the closing direction, the anchorage strength of the beam bars passing through joints is governed by the tail length of the upper bars, the concrete strength, and the diameter of the bars; whereas in the opening direction, the flexural strength of the joints is governed by the yield strength of beam or column bars, the amount of joint hoops, the column interior bars and projection length of beam or column bars in the joint. Predictions of the joint strength by the model presented in this paper agree well with the experimental results.