Buckling analysis of partially protected cold-formed steel channel-section columns at elevated temperatures

This paper presents a numerical investigation on the buckling behaviour of plasterboard protected CFS channel-section columns subjected to axial loading when exposed to fire on its one side. The work involves temperature-dependent pre-buckling stress analysis and buckling analysis. Two non-uniform temperature distributions with linear and nonlinear temperatures along the web and constant temperatures in flanges and lips have been included in this paper. Bernoulli beam theory has been used in the pre-buckling stress analysis with considering the effects of temperature on strain and mechanical properties. The buckling analysis is performed using combined finite strip analysis and classical Fourier series solutions, in which the mechanical properties are considered to be temperature dependent. The results show that the temperature distributions have a significant influence on both the pre-buckling stress distribution and slenderness of CFS column members. It is also found that the thermal bowing effect improves the buckling performance of intermediate CFS members, but deteriorates that of long CFS members. This paper gives a better understanding of the effect of non-uniform temperatures on the buckling behaviour of CFS columns, and further extends the potential application of the finite strip method to the buckling analysis of CFS members at elevated temperatures.