Experimental research on the creep buckling of fire-resistant steel columns at elevated temperature

The thermal creep is one of the major factors causing the buckle of steel columns in the fire events. But, few related studies have been reported to evaluate the factors affecting the thermal creep of steel column experimentally or numerically. In this study a series of Fire-resistant steel columns with three different slenderness ratios under a sustained load are tested under a uniform temperature up to six hours in order to evaluate the creep upon three selected factors, temperature, applied load, and column slenderness. Based on experimental results, a proposed creep strain rate model is established as the function of a single parameter of the load ratio of temperature <i>LR</i>(<i>T</i>) to determine the buckling time of steel column due to creep. Furthermore it is found that the creep can be neglected when <i>LR</i>(<i>T</i>) is smaller than 0.77.