Aluminium alloy channel columns: Testing, numerical modelling and design

Aluminium alloys can be employed in a wide range of structural applications offering high strength-to-weight ratio, whilst they can easily be extruded in various shapes. Channel (C-) sections have been increasingly employed as compression members, such as wall studs and chord members of roof trusses in framed residential and commercial buildings. However, relevant studies on their compressive behaviour are quite limited and thus a greater emphasis should be placed on providing a deeper understanding. Towards this direction, this paper examines the structural performance of C-sections under axial compression. An experimental and numerical investigation was performed on 6082-T6 heat-treated aluminium alloy C-section columns. In total, 6 fix-ended stub column tests were executed to examine the cross-sectional compressive behaviour, whilst 8 pin-ended column tests were conducted to study their minor-axis flexural buckling behaviour. The obtained experimental results were utilised to validate the developed finite element models. Subsequently, extensive parametric studies were carried out to generate additional performance data over a broad range of cross-sectional aspect ratios, and cross-sectional and member slendernesses. Both the experimentally and numerically obtained ultimate strengths are utilised to assess the accuracy of Eurocode 9 design provisions, including the flexural buckling curve. On the basis of the experimental and numerical results, a new flexural buckling curve is proposed improving the design accuracy. The applicability of the Direct Strength Method on the design of aluminium alloy C-sections subjected to axial compression is also evaluated resulting in the most accurate and consistent design strength predictions.