Analytical Solutions for the GNI Analysis for Lateral-torsional Buckling of Thin-walled Beams With Doubly-symmetric and Mono-symmetric Cross-sections

Abstract

When a beam is subjected to bending, lateral-torsional buckling (LTB) is a potential failure mode. LTB has extensively been studied in the past decades. It can be observed, however, that the vast majority of the research was devoted to beams with doubly-symmetrical crosssections subjected to major-axis bending. This is reflected also in the current design standards, e.g. in the Eurocode for steel [1]: the formulae for LTB check are most surely worked out for major-axis bending of doubly-symmetric cross-sections, and when it comes to N-M interaction check, mono-symmetric and asymmetric cross-sections are formally excluded. In the practice mono-symmetric and asymmetric cross-sections are used, too, they are especially typical in cold-formed steel (CFS) construction. Though there is a specific Eurocode part [2] for CFS members, the LTB, and especially the N-M interaction check is fairly simplified. Thus, it seems to be important to better understand the LTB behaviour of beams with monosymmetric or asymmetric cross-sections.