Behaviour and design of slender built-up nested cold-formed steel compression members

Built-up nested channel (NC) members, which are made of asymmetric cold-formed steel (CFS) lipped sections commonly used in various building applications Australia. The aim this research study is to provide suitable design guidelines for NC compression fail by global or local–global interaction buckling. Firstly, the rules current CFS standards and recently published studies were reviewed, their limitations members discussed. A test series was then conducted on single failed Based results, validated finite element (FE) models developed, followed a detailed parametric failing buckling different sections, lengths, end support boundary conditions as well screw sizes arrangements. FE analysis results to: (1) compare capacities with sum individual member capacities, (2) evaluate effect characteristics arrangements, (3) investigate methods past studies. Finally, based Direct Strength Method standards, simple reliable method proposed. This paper presents details including its findings.