Analysis of Creep Buckling of Steel Columns Subjected to Fire

One of the critical factors affecting the strength of steel columns at elevated temperatures is the influence of material creep. Under fire conditions, steel columns can exhibit creep buckling, a phenomenon in which the critical buckling load for a column depends not only on slenderness and temperature, but also on the duration of applied load. Although material creep and consequently the phenomenon of creep buckling can significantly impact the safety of steel columns subjected to fire, they have received relatively little research attention, and are not currently explicitly considered in code-based design formula for columns at elevated temperatures, such as those in the Eurocode 3 or in the AISC Specification. This paper will propose a preliminary methodology to study the phenomenon of creep buckling in steel columns subjected to fire. Preliminary analytical solutions are presented, and compared with computational predictions for creep buckling. The analytical and computational results clearly indicate that accurate knowledge of material creep is essential in studying creep buckling phenomenon at elevated temperatures. In addition, the results show that neglecting creep effects can lead to erroneous and potentially unsafe predictions of the strength of steel columns subjected to fire.