Behaviour of MCFST column-steel beam connection with side plates in the scenario of column loss

Four multi-partition concrete-filled steel tubular (MCFST) joints with double side-plate (DSP) were tested in the simulated scenario of progressive collapse. The main parameter in the test is the joint connection type. Two kinds of joints with discrete and consecutive DSP are studied. The load-deformation relationship of the specimens is discussed. Parametric analysis is also conducted by using a validated FE model. The results show that the failure of four MCFST joints with DSP is all caused by the fracture of the bottom beam flange. The configuration of discrete and consecutive DSP both could provide a reliable load-redistribution path for the joint to resist additional loads due to single column loss. Increasing the width of discrete DSP and the length of consecutive DSP could improve the resistance and decrease the deformation ability of the joint. It is suggested that the extensive length of DSP from column wall (L_C) should be larger than the width of the beam flange whilst the extensive height of DSP from beam flange (L_F) should be designed to be close to the half width of the beam flange. Parametric analysis indicates that relatively thin DSP could make the connection more flexible to develop catenary action which would provide larger collapse resistance.