After a brief review of the fundamental concepts concerning distortional -buckling and Generalized Beam Theory (GBT), the paper addresses a GBT-based general approach to derive "quasi-analytical" distortional buckling formulae for cold-formed steel members with arbitrary cross-section shapes and four end conditions. For illustrative purposes, this approach is used to obtain formulae for a family of thin-walled members with singly/point symmetric five/seven wall cross-sections, including a wide variety of cross-section shapes, such as rack-sections, hat-sections or channel and Z-sections with single/return lips. Finally, the accuracy, versatility and range of validity of the derived formulae are illustrated and discussed, on the basis of a set of numerical results (distortional buckling stresses) concerning members with different (ⅰ) cross-sections, (ⅱ) end conditions and (ⅲ) loadings. These results are compared with "exact values", obtained from exact GBT linear stability analyses, and, if possible, also with predictions yielded by other available formulae.
展开▼