Sensitivity assessment of steel members under compression

The objective of the paper is to analyse the influence of initial imperfections on the behaviour of a steel member under compression. The influence of the variability of initial imperfections on the variability of the load-carrying capacity studied has been calculated by sensitivity analysis. The advantages of Sobol’s sensitivity analysis and the most important properties of Sobol’s sensitivity indices are described. The Sobol’s first order sensitivity indices are evaluated in dependence on the nondimensional slenderness. The Sobol’s sensitivity indices are supplemented with a lucid elaboration based on the Monte Carlo method. Material and geometrical characteristics of a steel member IPE 220 were considered to be random quantities the histograms of which were obtained from experiments. Imperfections that have a dominant influence on the load-carrying capacity are identified.