PERFORMANCE OF PLANE FRAMES WITH CONCRETE FILLED STEEL TUBE COLUMNS AND STEEL BEAMS SUBJECTED TO LOCAL FIRE

A finite element (FE) model was proposed to simulate the performance of composite frames with concrete filled steel tube (CFST) columns and steel beams subjected to local fire. In the model, the heated members were simulated with shell elements and continuum elements while the other members were simulated with beam elements. The results of this FE model agreed well with those of test results. The FE model was then used to study the failure mode, the failure mechanism, the deformation and the internal force redistribution of the CFST frames. The results show that the CFST frames have two typical failure modes. The first failure mode is the local failure induced by the global buckling of the heated steel beam, and the second failure mode is the global failure induced by the heated column failure