Significance of local buckling for steel frames under fire conditions

This paper deals with the behaviour of steel structures under fire conditions, with emphasis on the influence of local buckling of steel sections on the response of frame members and subassemblages. A computationally-efficient temperature-sensitive model for steel which accounts for local buckling is described. The model is implemented within an advanced frame analysis program which represents both geometric and material nonlinearities. Several examples are presented to illustrate the effects of local buckling on the response of steel members at elevated temperature as well as on the fire resistance of idealised structural configurations. It is shown that whereas in many cases local buckling may have an insignificant influence on the fire resistance of isolated members, particularly when non-slender cross-sections are utilised, its effect should be accounted for when the interaction between the various structural members governs the overall fire resistance of the structure.