Performance of CFST-steel beam rigid connection under combined moment and tension

Beam-to-column connections are subjected to negative bending moment after service loads are applied to structures. However, when the vertical load path are cut off which is caused by column removal, the loads supposed to be sustained by the removed column are consequently sustained and spread by the beams connected to the removed column. In this case, the beam-to-column connections are under combined sagging moment and tension. In order to investigate the behavior of CFST-steel beam rigid connection under combined moment and tension, two kinds of common rigid connections were tested. The finite element models of the specimens were also developed and analyzed. The experimental and numerical results show that outer-ring connection has similar initial stiffness with overhanging diaphragm connection. They can both be considered as rigid connection. With the increase of tensile loads, the moment resistance of connections is decreased consequently. Tensile loads would influence the moment resistance of connections even under different initial moment level. Lower initial moment level would decrease the influence that tensile forces have on moment resistance of connection.