Global stability and strength of high-strength aluminium alloy T-section columns

AbstractHigh-strength aluminium alloys have found increasing applications in structural engineering due to their superior mechanical characteristics and outstanding durability against corrosion. However, research on the stability and design of aluminium monosymmetric section columns remains limited. To fill the research gap, the present study integrates experimental and numerical approaches to examine the buckling behaviour and performance of high-strength aluminium T-section columns. In the experimental programme, material tests, measurements of geometric imperfections and fixed-ended column tests were performed. Subsequently, numerical models were established and validated against test results, enabling parametric investigations across a wider scope of section geometries and specimen lengths. Based on experimental and parametric data, the reliability of the design rules in existing design codes for aluminium columns – including Eurocode and American Specification – was assessed. As a supplement, the applicability of the Direct Strength Method prescribed in the American Specification for cold-formed steel structures was also assessed. The results revealed that: (i) both the European and American aluminium design standards provide accurate and consistent resistance predictions for columns failing by flexural buckling; however, their predictions for flexural–torsional buckling exhibit greater scatter and tend to be conservative by up to 32%; (ii) the accuracy and consistency of Eurocode predictions are sensitive to local buckling interaction, for both flexural and flexural–torsional failure modes; (iii) the codified Direct Strength Method for cold-formed steel structures demonstrates the most accurate failure load predictions irrespective of failure mode, remaining overall conservative by about 12%, thereby demonstrating its applicability to the design of high-strength aluminium T-section columns.