Distortional-global interaction in lipped channel columns

This work presents and discusses numerical results concerning the post-buckling behaviour (elastic and elastic-plastic) and ultimate strength of cold-formed steel lipped channel columns experiencing distortional-global interaction. The analyses cover columns with (a) geometries selected to ensure very close global and distortional buckling loads, and (b) the support conditions usually adopted in experimental investigations: fixed-ended and pin-ended columns. A fairly large number of columns are analysed, differing in the initial geometrical imperfection shape and/or yield stress - the various initial geometrical imperfection shapes are linear combinations of the competing buckling modes with amplitudes equal to (a) 10% of the wall thickness, t (D) and (b) L/1000 (G). For clarification purposes, the column pure global elastic post-buckling behaviours are also addressed. These results are (a) elastic (mostly) and elastic-plastic non-linear equilibrium paths, (b) figures and curves providing the evolution, along the elastic paths, of column deformed configurations and, for the elastic-plastic columns, (c) figures showing the plastic strain location and growth, as well as the natures of the failure mechanisms.