Structural behavior of cold-formed thick-walled rectangular steel columns

Cold-formed rectangular steel columns with large and thick walls are increasingly applied in engineering recently. The section dimension and wall thickness have increased continuously to 800 and 22 mm, respectively, which causes the significant differences of cold-formed effects between cold-formed rectangular steel columns with thin and thick walls. Therefore, the mechanical performance and design method of cold-formed rectangular steel columns with thick walls should be studied. In this study, two section dimensions (700 mm × 20 mm and 600 mm × 16 mm) were selected for the axial load test and analysis of cold-formed rectangular steel columns with large and thick walls. The conclusions are as follows. (1) The indirect cold-formed rectangular steel columns have lower cold-formed effects than direct cold-formed rectangular steel columns. (2) Cold-formed rectangular steel columns with large and thick walls have high-bearing capacity under axial loads, which are manifested by local plate instability. (3) Calculation formula of ultimate bearing capacity with considerations to local plate buckling is proposed. The calculated and test results are in accordance with numerical simulation results.