Seismic performance evaluation of steel frame structures using self-centering prefabricated beam-column joints with weakened flange cover plates

Abstract

This paper continues the study of a novel self-centering prefabricated steel beam-column joint with weakened flange cover plates (WFCP-SCSJ). The seismic performance and the collapse performance of steel frames with WFCP-SCSJs (WSSF) were evaluated through numerical simulations. A six-story steel moment resisting frame was designed, considering various configurations and joint arrangements. Numerical models were established in OpenSees, and seismic time-history analyses and incremental dynamic analyses (IDAs) were carried out. Fragility curves were derived to assess the collapse resistance of different structural systems from a probabilistic standpoint. The results show that steel frames with WFCP-SCSJs exhibits superior seismic performance and self-centering capability, which meets the requirements in the Building Seismic Design Codes. Arranging WFCP-SCSJs on the inner side of the structural plane and along the weak axis effectively reduces the structural displacement response. Conversely, arranging WFCP-SCSJs solely on the first story of the structure leads to an abrupt change in structural stiffness and an increase in the displacement response. The failure probability of WSSF under different limit states is significantly lower than that of rigid-connected steel frames (RSF), and the collapse margin ratio (CMR) of WSSF is higher than that of RSF, indicating an excellent anti-collapse capability of the WSSF.