Buckling resistance of welded high-strength-steel box-section members under combined compression and bending

The global buckling resistance of welded high strength steel box section members subject to combined compression and bending was investigated through a numerical modelling programme. Finite element models were developed with the capability to accurately replicate the experimental results of the box section members under combined compression and bending. Extensive parametric studies were carried out to examine the global buckling behaviour of welded high strength steel box section members with a wide range of dimensions and member slenderness and steel grades of S460, S690 and S960 and subject to varying combinations of compression and bending. The effects of residual stresses and ultimate tensile strength-to-yield strength ratio on the global buckling behaviour of those members were investigated. The applicability of existing design rules to welded high strength steel box section members subject to combined compression and bending was evaluated using the results from parametric studies and the available experimental results in literature. The European, American and Australian standards provide conservative strength predictions for the structures. More accurate and safe strength predictions can be obtained based on European standard using the suggested column curves for the members while the design methods in Australian and American standards are safely applicable to the members.