Sensitivity and reliability analyses of lateral-torsional buckling resistance of steel beams

The presented paper deals with an analysis of the effects of random imperfections on the load carrying capacity of a steel beam, which is subjected to the effects of lateral-torsional buckling arising from equal and opposite end bending moments. The load carrying capacity of a hot-rolled steel beam was analyzed in the analytical form. Histograms obtained from experimental research were available for most imperfections. Realizations of the input imperfections were computed using the Latin Hypercube Sampling method. Global sensitivity analysis was used to identify those imperfections, whose variability has a dominant effect on the load carrying capacity. Sensitivity analysis identified three continuous intervals of beam slenderness in which the load carrying capacity is sensitive to different types of imperfections. Reliability of design according to the EUROCODE 3 standard was verified by performing the statistical analysis of the ultimate limit state.