Flexural buckling resistance of rectangular welded box section columns

Application of high strength steel (HSS – S420 and higher steel grades) is growing nowadays in the civil engineering praxis due to the numerous advantages compared to the normal strength steel (NSS – S235-S355). The accurate consideration of the flexural buckling resistance of HSS structures is highly important in the design. Higher yield strength indicates the applicability of smaller cross-sections, which might be more sensitive for stability problems. The purpose of the current study is (1) to investigate the flexural buckling behaviour of HSS welded rectangular box section columns and (2) to propose a reliable column buckling curve. Residual stress in steel structural elements have significant influence on the flexural buckling behaviour of welded box section columns. This phenomenon causes that hot-rolled, cold-formed and welded sections have different flexural buckling behaviour and resistance. Previous research results of the authors proved that different buckling curves can be used for HSS or NSS welded square box section columns. Research is continued and extended to the investigation of rectangular box sections, which significantly increase the applicability of the design proposals. The buckling resistances for NSS and HSS rectangular welded box section columns are determined by using deterministic numerical simulation technique for a wide range of relative slenderness and steel grades. Based on the simulation results buckling curves are proposed for all the analysed steel grades and aspect ratios. © 2021 The Authors. ce/papers published by Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.