Influence of boundary conditions and load eccentricity on strength of cold-formed lipped channel columns

The ultimate buckling strength of axially loaded cold-formed lipped channel columns is studied. Variations of boundary conditions and eccentricities of the applied load are considered. The strength is calculated by a geometrically and materially nonlinear FEM analysis. Numerical study is carried out for two columns previously analysed under fixed boundary conditions and centroidal load. Geometrical imperfections in the shapes of eigenmodes of the corresponding linearized buckling problem are assumed. For comparing the imperfections their sizes are set to a uniform level of an energy measure. Particularly the worst eigenmode imperfection is determined for each studied design case. By the corresponding lowest collapse loads the effects of varying boundary conditions and load eccentricities on the ultimate buckling strength of the columns are shown.