Laterally restrained stainless steel I-section beams under moment gradients: an experimental and numerical study
Author(s)
Su, Song
Yang, Zichang
Zhou, Feng
Gardner, Leroy
Li, Guo-Qiang
Type
Journal Article
Abstract
Moment gradients have been shown to benefit the local buckling capacities of steel beams, and thus can improve the cross-section design efficiency, which is especially important for stainless steel given its relatively high initial material cost. This paper investigates the local buckling behaviour and design of stainless steel I-section beams under moment gradients. Two four-point bending tests and six three-point bending tests were conducted on the laser-welded ferritic and duplex stainless steel I-section beams, with varying moment gradients taken into consideration. A Digital Image Correlation (DIC) system was employed to monitor the strain development in the upper flanges of the I-section beams during testing. Higher load-carrying capacities were observed in specimens with higher moment gradients. Finite element (FE) models were developed and validated against the test results. Parametric analyses were then conducted, encompassing a range of stainless steel grades, cross-sectional geometries and moment gradients. The ultimate bending moments from the tests and FE simulations were compared with the bending moment resistances predicted by the EC3 provisions and recent design proposals considering moment gradients, which were further developed by incorporation of the Continuous Strength Method (CSM). A reliability analysis was then conducted based on EN 1990. It was shown that the modified CSM, considering the effect of moment gradients, achieved the highest accuracy and adequate reliability among all existing design approaches for stainless steel I-section beams.
Date Issued
2026-11-01
Date Acceptance
2026-07-31
Citation
Engineering Structures, 2026, 366 (Part C)
ISSN
0141-0296
Publisher
Elsevier BV
Journal / Book Title
Engineering Structures
Volume
366
Issue
Part C
Copyright Statement
Copyright © 2026 Elsevier Ltd. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Article Number
123501
Date Publish Online
2026-08-05