Design of the cross-section of a steel composite bridge taking into account the buckling check according to EN 1993-1-5

As part of optimizing a steel composite section to determine whether longitudinal stiffeners could be omitted concerning plate buckling, a buckling tool was developed that implements both the effective width method (EWM) and the reduced stress method (RSM). These two methods are offered in addition to the finite element method in EN 1993-1-5 for buckling analysis. It was found that when using the formula given in EN-1993-1-5 for calculating the critical buckling stress of unstiffened buckling fields, which is independent of the acting stress distribution, the ratio of the elastic critical plate buckling stress to the elastic critical column buckling stress (σ_cr,p/σ_cr,c) is underestimated if the compressive stress is not uniform. This affects the detection of column buckling behavior. The most economical variant resulting from the optimization, the buckling tool, the influence of shear deformations combined with plate buckling, and the column buckling behavior of unstiffened buckling fields are presented in this paper.