Stainless steel I-section columns fire design considering the influence of loading history

The flexural buckling resistance of welded I-section stainless steel columns in fire considering the influence of the loading history is investigated in this paper. Finite element procedure used to replicate the response of stainless steel columns in fire has been developed and validated against existing experimental tests. Developed finite element procedure replicates real fire situation where column is firstly loaded and then heated until failure. Poor accuracy of the flexural buckling resistance according to the current Eurocode 3 design rules and recently proposed design rules was observed through an extensive parametric analysis, thus indicating that new contributing parameters need to be included in the design expressions. Two main contributing parameters were analyzed, ratio of the flange and web area A(f)/A(w) and ratio of the flange and web thickness t(f)/t(w). New flexural buckling rules were proposed and calibrated using the results from 3000 numerical simulations, according to the developed finite element procedure, considering a range of elevated temperature levels of practical importance, stainless steel grades, cross-sectional proportions and column slendernesses. The accuracy and reliability of new proposal were assessed against the results obtained through finite element procedure. Compared to the current Eurocode 3 design rules and recently proposed design rules, new proposal provides significantly more accurate prediction of flexural buckling resistance of stainless steel columns in fire.