Buckling Behavior of Circular Steel Tubes under Fire

Recently, several lives were lost because of the collapse of structures under fire. Steel members are mainly used in the columns and beams of buildings for improving construction efficiency. The fire resistance of steel structure is very important because when it don’t have fire resistive covering, it rapidly changes with high temperature. In fire resistance design of steel, steel structure must have fire resistive covering. But many facilities as temporary facilities, parking lot don’t have it. The buckling behavior of steel structures under fire is also significant because it can cause local buckling failure through the reduction in structural material properties by temperature. In this study, the elastic buckling behavior of a circular steel tube under fire was investigated using finite element analysis. The parameters for this analysis used were, diameter–thickness ratio, fire exposure area, and fire scenarios. The elastic buckling strength of circular steel tube rapidly decreased when subjected to the fire curve. Local buckling occurred and this can lead to global failure. When fire resistance design of circular steel tube was performed, buckling behavior must be considered.