Mechanical behavior analysis of concrete filled double skin steel tubular columns after high temperature

In order to analysis the mechanical behavior of concrete-filled double-skin steel tubular (CFDST) columns after high temperature, this authors design 24 CFDST columns, with appropriate constitutive parameters, and use ABAQUS finite element software for analysis. These parameters are compared with corresponding experimental parameters and good agreement is found. The influence of parameters such as axial pressure ratio, temperature and hollow rate on P-Δ curve is studied. In this paper, the working mechanism and the destruction mode of concrete pressure bending column of are analyzed. The results showed that when the temperature increases, the axial pressure ratio increases, and the transverse load capacity of the component decreases. As the temperature increases, the axial pressure ratio decreases, and the displacement ductility of the component becomes better. When the temperature is no more than 500℃, the flexural bearing capacity becomes larger with hollow components turning smaller. When temperature is over 500℃, the bearing capacity of bending members becomes larger with hollow rate turning larger. The hollow rate has little effect on the bending ability of the component.