Buckling Resistance of Axially Loaded Cold-Formed Steel Compound Sections: Numerical Simulation and Assessment of Codified Design Approach

Abstract The practical application of cold-formed high strength steel is becoming increasingly popular in structural engineering due to its great efficiency and cost effectiveness. However, cold-formed steel sections are usually associated with high slenderness, hence are susceptible to buckling failure. Consequently, the buckling resistance of steel struts made of cold-formed high strength steel must be determined with carefulness, particularly for complex compound sections. To this end, the present paper aims at investigating the behaviour of back-to-back channel sections made of S700 steel with a characteristic yield strength of 700 MPa. Compressive tests on such members are conducted for the purpose of validating the finite element models. Subsequently, a numerical parametric analysis is carried out on the buckling resistance of axially loaded cold-formed steel back-to-back channel sections, using the previously validated numerical modelling approach. In particular, the effects of stiffeners and number of bolts on the buckling resistance are investigated. Furthermore, the results of the parametric analysis are also compared with the codified buckling resistance determined based on the effective width method adopted in Eurocode 3 Part 1–3, in order to evaluate the reliability of the standardised design method for buckling resistance.