ABSTRACT To optimize the connection between the beam and the concrete‐filled steel tubular flat column (CFSTFC), a new connection using the vertical internal plates as stiffeners was proposed. In this paper, the seismic performance of the joint in the center column was studied by the quasi‐static test of two middle joint specimens with 10‐mm‐thick and 14‐mm‐thick steel tubes. The failure of the joint was concentrated in the beams, and the CFSTFC remained elastic. The tested joint showed good seismic performance. Changing the thickness of a steel tube has little influence on the stiffness, strength, and ductility of the rigid joint. Then, the influence of the axial compression ratio on the seismic performance of the joint was investigated by finite element analysis. With the axial force increasing, the seismic performance of the joint gradually decreased. Finally, a simplified fiber element model of the joint was proposed and validated by the test and solid element model results.
Shen et al. (Tue,) studied this question.