Vol. 20, No. 2, pp. 188-198 (2024)
TESTS, MODELLING AND DESIGN OF UNSYMMETRICAL BACK-TO-BACK
COLD-FORMED STEEL ANGLES UNDER COMPRESSION
Beulah Gnana Ananthi. G 1, *, Kushal Ghosh 2, Krishanu Roy 2, *, Asraf Uzzaman 3 and James B.P. Lim 2
1 Department of Civil Engineering, College of Engineering Guindy campus, Anna University, Chennai 600025, India
2 School of Engineering, The University of Waikato, Hamilton 3216, New Zealand
3 University of the West of Scotland, United Kingdom
*(Corresponding author: E-mail:This email address is being protected from spambots. You need JavaScript enabled to view it., This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it., This email address is being protected from spambots. You need JavaScript enabled to view it.)
Received: 22 May 2024; Revised: 15 June 2024; Accepted: 15 June 2024
DOI:10.18057/IJASC.2024.20.2.11
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ABSTRACT
Built-up cold-formed steel (CFS) unsymmetrical angles are increasingly used in structures such as portal frames, roof trusses, and transmission towers. However, there are limited studies on CFS unequal back-to-back angle columns (BBUAC) with stiffeners. This paper presents the results of six experimental tests on intermediate BBUAC with intermittent screw fasteners. The findings include the deformed shapes at failure and the load-axial shortening behavior. Additionally, a nonlinear finite element (FE) model that accounts for both material and geometric nonlinearity was developed. The experimental results were used to validate this FE model. The paper presents a total of 166 new data points, which include six concentric compressive tests and 160 finite element analysis (FEA) results on the compressive strength of BBUAC. The effectiveness of the current design rules, based on the Direct Strength Method (DSM), was also evaluated. The evaluation revealed that the current DSM is unconservative. As a result, a modified DSM approach is proposed.
KEYWORDS
Unsymmetrical back-to-back angles, Cold-formed steel, Axial capacity, Local buckling, Flexural buckling, Finite element modelling
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