Buckling resistance and residual stresses of welded HSS box columns

Welded box columns made of high‐strength steels (HSS) are characterized by high buckling resistance and low self‐weight. The residual stresses introduced by the welding process are of particular importance. In the area of the weld seams, the cooling process creates residual tensile stresses that are in equilibrium with the compression stresses distributed across the cross section. In Europe, the buckling resistance is insufficiently covered by the rules of EN 1993‐1‐1 and ‐1‐12. The present rules were validated for steel grades up to S355, so the application is quite conservative for columns made of HSS, especially in the medium slenderness range. As part of the IGF‐FOSTA research project P1588, residual stress distributions of welded box sections were determined for the steel grades S460–S960. The buckling resistance was investigated experimentally and by structural–mechanical calculations. The results led to recommendations for a revision of the buckling curve assignment and residual stress distributions of compression members with welded HSS box sections.