Compression members with slender Class 4 box sections susceptible to combined local and global buckling for use in steel arch bridges

This paper presents the results of a research project analysing some aspects of stability failure of thin-walled compression members likely to exhibit combined global and local buckling. In particular, the influence of various imperfections (namely residual stresses due to welding and local as well as global geometrical defects) on the load-carrying capacity was subject to detailed experimental and numerical investigations. The insight into the structural behaviour lead to a modification of the non-dimensional slenderness used in the global buckling verification and to the recommendation of a shift from the currently applied European buckling curve to a more favourable one in the case of non-stiffened members with welded box sections subjected to pure compression.