Direct Strength Method (DSM) design of end-bolted cold-formed steel columns failing in distortional modes

This work addresses the behaviour, ultimate strength and DSM design of end-bolted simply-supported cold-formed steel lipped channel columns failing in distortional modes - the end supports consist of a pair of cylindrical high-strength bolts with hexagonal heads and nuts, and inserted in standard-size holes located at the intersections of the flanges with the principal centroidal axis parallel to the web. After selecting the column geometries (crosssection dimensions and lengths) and yield stresses, ANSYS SFEA are used to acquire knowledge about their non-linear behaviour, strength and collapse, as well as to gather numerical failure loads. Together with the experimental failure loads previously reported by the authors, these numerical failure loads are then employed (i) to assess the merits of the available DSM distortional design curves and, in view of their inadequacy, (ii) to propose and validate new strength curves, aimed at providing efficient predictions for the whole failure load set considered.