Structural behaviour of built‐up battened cold‐formed steel columns

Built‐up cold‐formed steel (CFS) columns are extensively used when single cold‐formed steel elements are not able to fulfill the established requirements in terms of load‐bearing capacity. For hot‐rolled steel laced and battened columns, the EN 1993‐1‐1 presents specific design provisions. However, no specific design guidelines are provided for CFS laced and battened columns. The investigation on this type of built‐up elements is scarce, requiring extensive research to assess if the hot‐rolled design methodologies are also suitable for cold‐formed steel elements. In this investigation, experimental and numerical results are presented for CFS battened columns comprising C and Σ channels. Assessing the composite action between the individual shapes connected by the batten plates was one of the objectives of this investigation. The predominant buckling modes were analyzed considering the influence of batten plate spacing and the number of fasteners per plate. Based on the obtained experimental results finite element models were developed to further assess the influence of key governing parameters. The observed axial strengths are compared with design strengths determined according to the Eurocode assessing the suitability of the design methodologies.