Lateral torsional buckling of hot rolled channel sections – Numerical simulations and design proposal

This paper describes a parametric study addressing the resistance of U‐profiles (channel profiles) subject to bending and torsion to lateral torsional buckling. In case of U‐sections, the torsional moment results, in the majority of cases, from an unavoidable eccentricity of the applied load from the shear centre. The behavior and resistance of the studied members is addressed through a parametric study based on a numerical model validated with laboratory tests. This study is divided into two parts. First, U‐sections subject to bending only are studied in order to provide a method for this reference load case. In particular, the non symmetric stability behaviour of this type of section will be highlighted. Based on the numerical results an adaption of the European buckling curves is proposed. Then, the members are studied under combined bending and torsion. Existing design methods applicable to I sections are extended in order to account for the specific behaviour of U sections.