Out-of-plane stability design of stainless steel I-section beam-columns under moment gradients
Author(s)
Quan, Chunyan
Walport, Fiona
Kucukler, Merih
Gardner, Leroy
Type
Journal Article
Abstract
To address the limitations of existing design specifications for laterally unrestrained stainless steel I-section beam-columns, new design rules are proposed in this study. A comprehensive parametric study was conducted using finite element modelling to investigate the member behaviour and generate benchmark member resistances, covering Class 1–3 cross-sections and considering a range of material grades, member geometries and combined loading conditions. It was observed that the numerically derived compression-bending interaction factor for out-of-plane buckling checks decreases with more pronounced bending moment gradients, indicating their beneficial influence on member resistances. Thus, calibrated against the numerical results, a new formulation of the interaction factor is proposed, covering combined compression and uniform or non-uniform bending and ensuring alignment between member buckling and cross-section resistance checks. The new proposals are shown to provide accurate and consistent member resistance predictions for all load cases, and can be applied with the partial safety factor of 1.1 as specified in EN 1993–1–4:2025. These proposals have been included in the new version of the European structural stainless steel design standard EN 1993–1–4:2025.
Date Issued
2026-03-15
Date Acceptance
2025-12-06
Citation
Engineering Structures, 2026, 351
ISSN
0141-0296
Publisher
Elsevier BV
Journal / Book Title
Engineering Structures
Volume
351
Copyright Statement
© 2025 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published
Article Number
121939
Date Publish Online
2026-01-02