Cold-formed steel (CFS) claddings are increasingly used in bushfire prone areas in Australia due to their non-combustibility and are recommended in the Australian standard AS 3959 for the design of buildings in bushfire prone areas. Thus, good knowledge and understanding of their behaviour at elevated temperatures is important for the safe design of buildings. However, the elevated temperature mechanical properties of thin CFS cladding profiles have not been investigated. Hence, this research investigated the elevated temperature mechanical properties of high strength CFS cladding profiles through steady-state tensile coupon tests. More than 100 coupons, taken from the crests of three different cladding profiles with thicknesses of 0.42 mm and 0.48 mm, were tested to failure at predetermined elevated temperatures. The elevated temperature mechanical property results were compared with corresponding results from previous studies conducted on CFS sheets and sections, and the predictions obtained from the Australian CFS design standard. These comparisons showed that currently available equations can be used to determine the elevated temperature stress–strain curves and mechanical properties of CFS cladding profiles except for ultimate and fracture strains. Since no suitable equations are available for ultimate and fracture strains of CFS at elevated temperatures, new equations are proposed for CFS with varying thicknesses.

由于不燃性，冷弯型钢（CFS）包层在澳大利亚易发生大火的地区越来越多，并在澳大利亚标准AS中推荐使用 3959年在丛林大火易发地区设计建筑。因此，对它们在高温下的行为的充分了解和理解对于建筑物的安全设计很重要。但是，尚未研究薄CFS覆层轮廓的高温机械性能。因此，本研究通过稳态拉伸试样试验研究了高强度CFS覆层型材的高温机械性能。在预定的高温条件下，测试了从厚度为0.42 mm和0.48 mm的三个不同包层轮廓的波峰中抽取的100多个试样。将高温机械性能结果与先前在CFS板材和型材上进行的研究得出的相应结果进行了比较，以及根据澳大利亚CFS设计标准获得的预测。这些比较表明，除了极限应变和断裂应变，当前可用的方程式可用于确定高温应力-应变曲线和CFS覆层轮廓的力学性能。由于在高温下没有合适的方程式可用于CFS的极限应变和断裂应变，因此针对厚度变化的CFS提出了新的方程式。