Numerical studies on restrained cold-formed steel column subjected to transient thermal loading

Abstract

Cold-Formed Steel (CFS) is widely used in all types of buildings as load-bearing and non-load bearing members. The codes IS 801, AS/NZS 4600, BS 5950, EN 1993-1.3 and Direct Strength Method (DSM) are used to design the CFS elements at ambient temperature and EN1993-1.2 allows the design elements with limiting temperature of 350 °C by assuming CFS as slender sections. Several studies have reported on the behaviour of cold-formed compression members subjected to elevated temperature by experimentally and numerically under steady-state temperature condition and minimal studies on the transient temperature condition. In this paper, the restrained CFS channel compression members' buckling behaviour in transient state condition is studied numerically. The numerical model is calibrated with the past experimental work. A parametric study has been conducted by varying the member's slenderness ratio and width to thickness ratio of the section. Based on the results, it is found that the peak and critical temperature of the column reducing with the increase in the initial applied load level and the width to thickness ratio of the section. Also, it is observed that the failure mode of the long column is different from the short column under thermal loading. The buckling curves of the compression members under axial load are presented based on the parametric study.