Local plate buckling type imperfections for NSS and HSS welded box-section columns

The finite element model-based design of steel structures is getting increasing attention by designers, especially in the case buckling problems welded plated and static check interacting stability behaviour. FEM-based approach introduced standardised EN 1993–1-5 Annex C providing ability to calculate resistance based on direct geometrical material non-linear analysis using imperfections (GMNIA). By this process, application (shape magnitude) has a large impact computed resistance. It true if phenomenon (interaction plate column-like behaviour) be analysed. general way consider FE models equivalent geometric covering effect residual stresses imperfections. Several previous investigations prove can lead conservative resistance, problem because two different leads duplication stresses. Therefore, it highly important determine appropriate imperfection shape size for problems. current paper deals with determination local buckling-type imperfection, which further applied numerical used problems, next step planned research program. Within paper, necessary magnitudes are determined square box-section columns various grades (S235 – S960) perfectly match proved test results gives proposals approaches.