Hysteretic behavior and moment-rotation model of self-centering beam-column connection with angle steel

The objective of this study is to develop a moment-rotation model (M-theta) to evaluate the hysteresis behavior of self-centering beam-column connection with replaceable angle steel. Based on the previous pseudo-static test results of 13 groups of 22 beam-column joint specimens, the hysteretic behavior of the joint and the prestress loss of the post-tensioned (PT) strand are further studied. According to the phased hysteretic characteristic of the beam-column joint and the connection characteristic of two interfaces, the M-theta model for beam-column connection is established, which is divided by four key points: opening point, yield point, peak point and ulti-mate point. The proposed M-theta model includes the bilinear moment-rotation (M-theta s) model of the endplate-bolt interface based on the component method, and the trilinear moment-rotation (M-theta r) model of the self-centering interface considering the prestress loss of PT strand and the phased mechanical behavior of each component. The accuracy of the proposed M-theta model is verified by the comparisons of theoretical calculation results and experimental skeleton curves, which provides a theoretical basis for the engineering design of this kind self-centering beam-column connection.