LAUSR

Abstract Due to its cost-effective nature and satisfactory seismic performance, semi-rigid steel frame is often considered as an alternative to conventional fully rigid steel frames. To date, the seismic behavior of semi-rigid connection has typically been documented in two dimensions. To fill this gap, an experimental investigation was made to study the behavior of the internal semi-rigid joints through spatial quasi-static tests with loads applied to the ends of the columns from both the major and minor axes. In our newly proposed semi-rigid joint, the minor beam is attached to the column web by an end-plate connection and the major one attached to the column flange by a T-stub connection, where the loading effect from the minor direction on the major direction of semi-rigid joints was considered. Results show the major beams failed with T-stub fractures and the minor beams failed with substantial bending deformations at the end-plates, which are easy failures to repair. In addition, the initial rotational stiffness and angular ductility coefficient of the minor beam decreased with increases in the thickness of the end-plate. Compared with the semi-rigid steel joints with T-stub connections in both axes, the major beams of our proposed joints exhibited obviously increased bending resistances, equivalent viscous damping coefficients and equivalent energy dissipations.