Flexural buckling and flexural–torsional buckling behaviour of S960 ultra-high strength steel (UHSS) welded T-section columns

The structural behavior and resistance of S960 ultra-high strength steel (UHSS) welded T-section columns were investigated through comprehensive tests and numerical simulations in this paper. The experimental program was conducted on a total of ten S960 UHSS welded T-section column specimens, including the material tensile coupon tests, the measurements of initial geometric imperfections and the pin-ended column tests. In addition to the experiments, numerical simulations were performed. The finite element (FE) models were initially developed and validated in accordance with the test results, and then the validated FE models were utilized for parametric studies to generate additional numerical data. The applicability of the relevant design clauses in the European, American and Australian codes was evaluated based on test and numerical data pool. The evaluation results indicated that all three design standards offered rather conservative resistance predictions for S960 UHSS welded T-section columns failing by flexural buckling and flexural‒torsional buckling. Finally, a new design method based on the continuous strength method has been proposed, offering more accurate resistance predictions than the current design provisions.