Analysis of Finite Element Mechanism of Axial Compressive Behavior of T-Shaped Stiffened Concrete-Filled Steel Tubular Stub Columns After Uniform Fire Exposure

Based on the reasonable determination of material constitutive relationship and interaction model between concrete and steel tube, a finite element model of T-shaped stiffened concrete-filled steel tube (TSCFST) stub column exposed to uniform fire was established, and model reliability was verified. Through the FE model, the working mechanism of the model in the whole process of loading was analyzed in detail. In the process of axial compression, the load distributions of steel tube and concrete, and the interaction between steel tube and concrete were discussed. This paper analyzed the effects of the main factors on residual bearing capacity of TSCFST stub columns, and put forward the calculation formula of the residual bearing capacity of TSCFST stub columns after uniform fire exposure.