Investigation of trapezoidal steel claddings under combined wind and bushfire conditions

Crest-fixed trapezoidal steel sheeting with wide pans are extensively utilized as external building envelopes in bushfire-prone regions of Australia. However, it experiences localized pull-through failures caused by transverse splitting at its screw connections when exposed to combined wind and bushfire conditions. This can lead to the loss of the entire roof sheeting, allowing embers to cause significant fire damage. In this study, a finite element model of trapezoidal steel cladding with wide pans was developed to simulate transverse splitting and dimpling-type pull-through failures. Following its validation, it was used to investigate the behaviour of cladding at elevated temperatures. The results indicate changing failure modes and a reduction in pull-through failure capacity as the temperature increased. This paper presents the details of the developed finite element model and the important results relating to the behaviour and capacity of steel claddings under elevated temperature conditions.