Seismic performance of steel beam-to-column moment connections with different structural forms

Abstract

A novel scheme of steel moment connections shared by flange cover-plate strengthening and web opening weakening is proposed in this study. Four steel beam-to-column moment connections with different structural forms (standard connection, cover-plate reinforced connection, web-opening weakened connection, and equal strong (ES) connection) were tested under cyclic loading. The effects of the local structural forms at the beam end on the failure modes, bearing capacity, strength and stiffness degradation, and ductility and energy dissipation capacity of the connection were analyzed and discussed. The test results indicate that the connections with local structural forms achieve satisfactory ductile behavior by the plastic hinge moving outside. The strength and stiffness degrade gradually owing to a large plastic strain accumulation, and the plastic deformation capacity and energy dissipation capacity improve significantly. Specifically, compared to the standard connection, the displacement ductility coefficient and cumulative energy dissipation of the ES connection increased by 20.0% and 27.9%, respectively, under the premise that maximum strength and initial stiffness remain unchanged, indicating superior seismic performance. Moreover, finite element analysis considering a stress triaxiality dependent fracture criterion was performed, and demonstrated good agreement with the experimental results. Based on the experiment and numerical simulation, the feasibility of the ES connection was verified to provide practical design applications.