Behavior of Double Layer Compound Cold-Formed Steel Columns

Cold-formed steel is widely used in the construction industry due to its lightweight properties, making it a cost-effective alternative to conventional construction methods. With a weight comparison, its lighter than regular steel, and a better weight-to-strength ratio (Senthilkumar et al. in Structures 44:487–502, 2022), and it is commonly used in load-bearing applications on prefabricated structures. Cold-formed steel is available in various thicknesses, ranging from 0.1 mm to 7.9 mm, allowing it to be selected according to specific structural requirements and aesthetic preferences. The material can be easily shaped either by cold rolling or press braking, to form unique shapes such as zeta, lipped z, and Sigma. In this study, a 2 mm thick cold-formed steel sheet was bent into a 100 mm × 50 mm × 8 mm c-lipped channel, which was then combined into a box column using welding face-to-face. The box column was then fitted with four different shapes, namely Zed section, rectangular, channel, and L angle, to form four different compound sections. The aim of the research was to determine the maximum load-carrying ability of these four compound steel columns (Babu and Selvan in Mater Today: Proc, pp 3069–3073, 2020) and their buckling behavior (Babu and Selvan in Mater Today: Proc, pp 3069–3073, 2020). This was achieved by designing and analyzing the different compound sections using ABAQUS finite element software(Kyprianou et al. in Proceedings of the 9th international conference on advances in steel structures, ICASS 2018. Hong Kong Institution of Steel Construction, 2020). The results were then compared with the findings from the experimental method conducted using a column axial load testing machine, where the buckling behavior was studied using LVDT. Through this study, the best compound section among the four different models was identified by comparing their buckling and axial load-carrying capacities(Liu et al. in J Constr Steel Res 191, 2022). Overall, cold-formed steel is an effective and versatile material for construction projects, offering a range of benefits, including lightweight properties, cost-effectiveness and ease of shaping (IS 801-1975 in Indian Standard code of practice for use of cold-formed light gauge steel structural members in general building construction, 1975).