Cross-sectional compressive capacity of S1200 ultra-high-strength steel welded I-section stub columns: Testing, modeling and design

This paper reports experimental and numerical studies on the compressive behavior and load-carrying capacity of S1200 ultra-high-strength steel (UHSS) welded I-section stub columns. A testing program was first conducted, involving material coupon tests, residual stress measurements and 14 stub column tests. Following the testing program, a numerical modeling program was conducted, where finite-element models on S1200 UHSS I-section stub columns were developed and validated. The validated models were then used to perform parametric studies to obtain supplementary numerical data. The obtained test and numerical results were adopted to perform a comprehensive design analysis, where the existing steel design standards used in Europe, America and Australia were examined for their applicability to the design of S1200 UHSS I-section stub columns. The design analysis results generally indicate that, among the three considered design standards, the American specification provides the highest overall prediction accuracy for both non-slender and slender I-sections. The Eurocode 3 also shows good agreement for non-slender I-sections; however, its predictions become slightly conservative for slender I-sections. In comparison, the Australian standard yields the lowest prediction accuracy, particularly for slender I-sections, where pronounced conservatism and larger discrepancies relative to the obtained test and numerical results are observed. Overall, the findings demonstrate that the American specification is the most suitable for the design of S1200 UHSS welded I-sections.