Structural Performance of Light Gauge Steel Compression Members at Elevated Temperatures

Despite the importance of fire safety design of building structures, the structural behaviour of light gauge cold-formed steel members under fire conditions is not well understood. The light gauge steel members are susceptible to various buckling modes including distortional buckling. The distortional buckling effects associated with thin and high strength steel members are significant and the effects of fire conditions on the distortional buckling behaviour are not known. Therefore a research project was undertaken to investigate the distortional buckling behaviour of light gauge cold-formed steel members under axial compression. It included tensile coupon tests to determine the mechanical properties and detailed laboratory experiments and numerical analyses of channel members subject to axial compression at elevated temperatures up to 800 degrees Celsius. The results were compared with the current design rules and appropriate modifications were proposed. This paper presents a summary of the results from this investigation on the distortional buckling behaviour of cold-formed steel columns.