Tests of cold-formed normal and high strength steel tubes under tension

The construction field has a widespread usage of cold-formed steel tubular members in various types of structures. In recent decades, extensive research studies have been carried out on cold-formed steel hollow sections under various loading conditions. However, there is a lack of research study on the tensile performance of cold-formed steel tubular sections with the whole cross-section under tension. Therefore, the focus of this study is to investigate the structural behavior of cold-formed steel tubular sections with and without circular perforations under pure tension through experimental investigation. Eleven cross-section series made of cold-formed normal and high strength steel were considered. The nominal outer dimensions of hollow steel tubes ranged from 20 to 100 mm and the nominal wall thicknesses ranged from 1.5 to 8 mm. The mechanical properties were determined through tensile coupon tests. The measured 0.2% proof stresses ranged from 323 to 795 MPa. A total of 24 tensile tubular specimens, including twelve specimens with circular holes and the rest without hole, were tested with full cross-section under pure tension. Tensile test results of cold-formed steel tubular sections were discussed and compared with the tensile capacities predicted by the North American Specification, the Australian/New Zealand Standards and the European Code. The comparisons show that the existing design rules provide quite conservative and reliable tensile strength predictions for cold-formed steel tubular sections.