Equivalent geometric imperfection for interaction buckling of welded box-section columns - Stochastic analysis

The current paper investigates recently developed GMNIA-based equivalent global and local imperfections to be applicable in the FEM-based design of welded box-section columns. While these imperfections were developed independently for the local and global buckling problems, their applicability to coupled instability problems has not yet been investigated. Therefore, this study addresses this gap by investigating the effectiveness of these imperfections in predicting pure local, global and interaction buckling capacities by comparing them against accurate stochastic analyses using Monte Carlo simulations. The current simulations take into account the variations in geometrical and material properties as well as the imperfections, leading to a highly accurate estimation of the buckling capacity of welded box-section columns. Statistical measures are used to assess the accuracy of each imperfection type and imperfection combination. The discrepancy in deterministic resistance resulting from the application of imperfections and combinations is assessed by comparing them with the accurate buckling resistance. Based on the statistical evaluation, the numerical model uncertainty is also evaluated, serving as the input data of the model factor calculation. The present paper gives a unique introduction to the calculated model factors and presents its calculation methodology for local and global buckling problems.