PERFORMANCE ANALYSIS OF CONCRETE-FILLED SQUARE STEEL TUBULAR COLUMNS WITH INTERNAL PROFILED STEEL UNDER THREE-FACE FIRE CONDITIONS

A finite element (FE) model of concrete filled square steel tubular column with internal profiled steel under standard fire conditions was developed using ABAQUS software. The FE model was verified with experimental results. The loading versus axial displacement curves were calculated in overall stage fire conditions, and loading versus lateral displacement curves were also studied. The stress distribution was analyzed in loading at the ambient stage, heating stage, cooling stage, and post fire stage. The results under loading at major axis and secondary axis were compared. The main parameters that affected the residual bearing capacity coefficients after exposure to full stage fire conditions were analyzed. The results show that the fire loading ratio, fire duration time ratio, and the slenderness ratio of column have significant effect on the residual bearing capacity.