ANALYSIS ON CONCRETE-ENCASED CFST COLUMNS UNDER FIRE

In order to know about the mechanical properties of concrete-encased CFST (concrete-filled steel tube) columns during both the heating and cooling phases of a fire, a finite element analysis (FEA) modeling of concrete-encased CFST columns under the combined load and fire including heating and cooling phases is established using ABAQUS software, and the FEA modeling is verified by relevant test data. Based on the FEA modeling, the temperature distributions, failure modes, deformations and internal force redistribution of concrete-encased CFST columns under both loading and fire exposure are analyzed. The study shows that the most of loads are borne by the steel tube since the strength of the outer concrete is weakened under high temperature, and there is a phenomenon of an internal force redistribution in the concrete-encased CFST column during the heating and cooling fire.