Evaluation of nonlinear buckling analysis of stepped beams subjected to natural fire scenarios

This research explores the effect of flux heat loads on the lateral torsional buckling (LTB) behavior of unrestrained stepped steel beams. By characterizing the flux energy input and examining its application at different locations, it identifies critical temperatures at failure points (LTB occurrence) to understand the thermal conditions leading to buckling. Transient state analyses under varying thermal loads emphasizes the increased susceptibility towards LTB of stepped beams in localized fire scenarios. These findings provide a comprehensive understanding of enhanced performance of stepped steel beams in comparison with prismatic beams under natural fire.