On the post‐buckling rotational capacity of square hollow sections in uniform bending

Abstract

AbstractNominated for the Bernt Johansson Outstanding Paper Awards at Nordic Steel 2019The growing popularity of high‐strength steel grades leads to the need for more accurate design specifications, with the aim of fully exploiting the material benefits and creating economic advantages. According to Eurocode 3, the maximum rotational capacity of a section is limited and linked to the definition of cross‐sectional classes. For class 1, the rotational limit θ is assumed to be ”infinite“, whereas it drops significantly for classes 2 and 3 to a maximum rotation of φpl and φel, respectively. In reality, despite their lower hardening capacity and ultimate strains, high‐strength steel sections exhibit a non‐negligible rotational capacity that exceeds these code predictions, which were developed for mild steel and with a level of analysis in mind that is suitable for hand calculations. In order to achieve greater use of high‐strength steel sections, it is thus very important to understand and be able to predict a section's deformation and rotational capacity more accurately, with the aim of implementing the findings in tools for advanced, FEM‐based design by analysis (DbA) approaches. As an initial step in this direction, this paper shows the results from numerical calculations of the rotational capacity of HSS rectangular hollow sections. The numerical results were calibrated against laboratory tests. Consequently, different rectangular cross‐section dimensions and variations of the steel grade and thickness were chosen and analysed in the ABAQUS finite element software.