Experiment on Seismic Performance of Diaphragm-Through Joint Between Concrete-Filled Square Steel Tubular Column and Steel Beam

Four full-scale cruciform specimens were subjected to low-reversed cyclic loading to investigate the seismic performance of diaphragm-through joint between concrete-filled square steel tubular column and steel beam.The failure process and feature of each specimen were described and load-carrying capacity,ductility,energy dissipation,rigidity degeneration were analyzed.Results show that the specimens of diaphragm-through joint have stable hysteretic characteristic and enough energy dissipation capacity.Details of the steel beam flange connecting with the diaphragm have obvious effect on the ductility,energy dissipation and rigidity degeneration,and joints with fillet slopes at the connecting zone are better than those reinforced by taper plate welded to the beam flanges and diaphragm with regard to the seismic performance.Diaphragm thickness,diameter of concrete cast hole and width-to-thickness ratio of the tube have less influence on joint seismic behavior.However,the concrete filled in the tube can greatly increase the joint rigidity,reduce shearing deformation of joint panel zone and enhance the seismic performance of diaphragm-through joint.