A novel DSM-based approach for the rational design of fixed-ended and pin-ended short-to-intermediate thin-walled angle columns

This paper deals with the development of novel procedures for the design of fixed-ended and pin-ended equal-leg angle columns with short-to-intermediate lengths, i.e., those buckling in flexural-torsional modes. Initially, numerical results concerning the buckling and post-buckling behaviour of the above angle columns are presented, (i) highlighting the main differences between the fixed-ended and pin-ended column responses, and (ii) evidencing the need for specific design procedures. Then, the paper gathers a large column ultimate strength data bank that includes (i) experimental values, collected from the available literature, and (ii) numerical values, obtained from Abaqus shell finite element analyses. The set of experimental results collected comprises 41 fixed-ended and 35 pin-ended columns, and the numerical results obtained concern 337 fixed-ended and 197 pin-ended columns - various cross-section dimensions, lengths and yield stresses are considered. Next, after reviewing the available methods to estimate the ultimate strength of angle columns, the paper develops new design approaches for fixed-ended and pin-ended columns, based on the direct strength method (DSM) - the mechanical reasoning behind the procedures proposed, which include the use of genuine flexural-torsional strength curves, is also provided. Finally, the paper closes with the assessment of the ultimate strength predictions yielded by the proposed DSM design procedures, through their comparison with the assembled experimental and numerical failure loads - it is shown that both the quality and reliability of these predictions are very good and slightly higher than those exhibited by the available design methods for angle columns.