Warping torsion on slender box sections – buckling analyses and simplified design verification
Steel members subjected in torsion often have box sections. In general, such sections show warping effects and therefore also local warping stresses (σω, τω) arise, beside torsional shear stresses τsv. The main object of this work is to clarify, whether for slender sections a buckling verification of an isolated section member (web or chord) with torsional shear stresses τsv only, gives accurate results. First an analysis of the warping stress fields of different box sections (variation of geometry, thicknesses of web and chord and member length) is presented. Based on a preliminary buckling verification, with and without warping stresses, representative cases are selected. For this individual box section members comprehensive GMNIA‐analysis were done, on the overall system (including all warping effects) as well as on the isolated web plate without warping effects. In addition, also members with torsion and additional axial forces or bending moments are analysed.