A theoretical model for local buckling of FRP-confined CFST columns
Author(s)
Long, Yue-Ling
Yue, Xiang-Hua
Ge, Sheng
Gardner, Leroy
Wadee, M Ahmer
Type
Journal Article
Abstract
A theoretical model for the local buckling of FRP-confined concrete-filled steel tubular (CFST) columns under axial compression is proposed. The formulae for the elastic local critical buckling stress of the steel tube in FRP-confined CFST columns are derived using energy methods. Subsequently, a finite element (FE) model for local buckling of FRP-confined CFST columns is developed in order to verify the proposed model. The proposed model is calibrated with results from the FE model and tests, which exhibits good agreement. The proposed model is subsequently employed to investigate local buckling behaviour of the steel tube in FRP-confined CFST columns. It is found that the local critical buckling stress of the steel tube in FRP-confined CFST columns is significantly influenced by both the tensile stiffness ratios of FRP jackets to the steel tube, and the diameter-to-thickness ratios of the steel tube. The local critical buckling stress of the steel tube decreases with increasing diameter-to-thickness ratios of the steel tube, whereas the local critical buckling stress of the steel tube increases with the increase of the tensile stiffness ratios of FRP jackets to the steel tube at a specified value of diameter-to-thickness ratio. Furthermore, limitations on the diameter-to-thickness ratios of the steel tube in FRP-confined CFST columns are suggested for structural engineering practice. Finally, a novel concept, an equivalent thickness of the steel tube contributed by the FRP jackets, is proposed, resulting in a unified equation for the critical buckling stress of steel tubes in both FRP-confined CFST columns and conventional CFST columns.
Date Issued
2026-07-01
Date Acceptance
2026-03-16
Citation
Engineering Structures, 2026, 358
ISSN
0141-0296
Publisher
Elsevier BV
Journal / Book Title
Engineering Structures
Volume
358
Copyright Statement
Copyright © YYYY Copyright Owner. 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
Accepted
Article Number
122619
Date Publish Online
2026-03-31