Built-up back-to-back cold-formed steel compression members failing by local and distortional buckling

The current design methods for built-up back-to-back cold-formed steel (CFS) channel compression members are considered inadequate despite several research studies in recent times. These have proposed improved DSM based equations, however, they general led to predictions of varying accuracy. Further, there were some contradicting observations regarding the effects screw connections on their behaviour and capacities. Therefore, this focused capacity CFS sections subject local and/or distortional buckling. It included tests short single failing by local-distortional interaction buckling, development validation finite element models finally a parametric study examine fastener characteristics arrangements capacities Using results, accuracy currently available equations standards recently published papers was investigated simple method is recommended. This paper presents details results including its findings. • Investigated (BC) Evaluated composite action web buckling compatibility BC members. Capacities or about twice individual member capacity. Recommended simplified reliable approach equations.