Structural behaviour of cold-formed thin-walled short steel channel columns at elevated temperatures. Part 1: experiments

Cold-formed thin-walled steel structures are increasingly being used as primary load bearing members. However, there is a lack of study of their performance in fire. This paper presents a detailed description of an experimental study of the axial strength of cold-formed thin-walled channel sections under ambient and uniform high temperatures. The objectives of this study are two-fold: to gain an insight into the physical behaviour and failure modes of this type of structure and to provide some experimental results for detailed numerical studies. A total of 52 strength tests were carried out on short cold-formed lipped channels with and without service holes and unlipped channels at ambient and various elevated temperatures. From these experimental studies, it has been observed that the failure mode of two nominally identical columns can be different even though the failure loads are close. Depending on the thickness of a channel and the location of the service hole, perforation can have an important effect on the strength of the channel, irrespective of the temperature. The companion paper will describe the results of design calculations and numerical studies.