Lateral impact behaviour of square CFST columns under fire condition

Abstract

This paper reports a numerical investigation into the lateral impact behaviour of concrete-filled steel tubular (CFST) columns in fire. A coupled finite element (FE) model of square CFST columns under fire condition subjected to lateral impact is developed and verified. The full-range analysis on the impact behaviour of CFST columns under fire condition is carried out, namely the impact process, the development and distribution of the internal forces, the damage evolution, and the energy absorption. The impact responses of columns under different fire damage are also compared in detail. It shows that increasing the fire time causes a significant reduction in the impact resistance and energy absorption capacity of CFST columns that have the smaller plateau impact force and dynamic bending moment but larger mid-span deflection and impact duration. Various parameters affecting the impact responses of CFST columns under fire condition are further analyzed, and the simplified methods are finally proposed to evaluate the impact responses of CFST columns under fire condition, i.e., the dynamic flexural capacity, the maximum mid-span deflection and plateau impact force.