Experimental study of pull-through failures in cold-formed steel battens under combined wind and elevated temperature conditions

Cold-formed steel (CFS) claddings are popularly used in bushfire zones because they are non-combustible. Yet, under the intense heat and strong wind action during bushfires, their safety demands closer scrutiny due to localised pull-through failures of CFS battens at the screw connections. While the pull-through capacities of batten screw connections have been well-studied at ambient temperature, the bushfire enhanced wind effect on pull-through failures in CFS batten screw connections has not been studied at elevated temperatures. This study fills that gap, using a comprehensive testing program encompassing 144 short batten, 22 two-span, and 12 large-scale tests. Employing three thicknesses and two steel grades, it examines the critical pull-through failure behaviour of battens under elevated temperature conditions, including six temperature variations and three screw types. New design equations and capacity reduction factors for pull-through capacities are developed, accounting for both wind suction loading and elevated temperatures. These findings equip engineers and builders with vital knowledge to create safer structures in bushfire-prone regions, a crucial step towards resilient communities.