Cold-formed steel composite columns: axial strength and deformation response

The past findings on lightweight steel composite columns are minimal. Therefore, there is a grave need to carry out studies in this area to address the deficit. This paper presents an experimental investigation on the compression tests on cold-formed steel lightweight composite columns. The column models were fabricated using unstiffened channel sections, connected in the toe-to-toe arrangement by battens to form closed built-up sections. Pultruded glass fibre-reinforced polymer planks were used as lightweight material to strengthen the web of the thin channel sections against the inherent local buckling characteristics of thin-walled sections. The height of all the models was kept constant. However, the sectional compactness of the channels, the number of intermediate battens, the geometric details of the built-up sections and the number of glass fibre-reinforced polymer planks were varied. The assessment of the structural behaviour was carried out in terms of ultimate strengths, load vs. axial shortening response, failure modes and axial stiffness parameters. It was found that glass fibre-reinforced polymer planks improve the strength and stability features of cold-formed steel lightweight composite columns without adding much self-weight.