Numerical investigation on thin-walled CFS columns in fire

Abstract

The structural performance of cold-formed steel compressed elements subjected to fire is investigated using finite element analysis. The numerical study is based on a set of experimental tests on cold-formed steel columns subjected to fire with restrained thermal elongation. On the fire resistance tests, different levels of restraint and load were considered. This allowed studying the influence of the generated internal forces during heating in the overall structural fire behavior of the cold-formed steel columns. Specifically, in this study, two cross-section shapes are investigated, namely C-channels and Sigma-channels (sigma). Based on experimental results the numerical models were developed and calibrated using all mechanical and thermal properties determined experimentally at both ambient and elevated temperatures. To further investigate the influence of some key parameters, such as initial applied load level, level of restraint to thermal elongation and slenderness, a parametric study is presented. The level of restraint to thermal elongation will significantly influence the critical temperature of the cold-formed steel columns.