Channel columns undergoing local, distortional, and overall buckling

Abstract

The paper presents design and numerical investigations into the strengths and behavior of cold-formed lipped channel columns using finite element analysis. A nonlinear finite element model is developed and verified against fixed-ended channel column tests. Geometric and material nonlinearities were included in the finite element model. It is demonstrated that the finite element model closely predicted the experimental ultimate loads and the behavior of the cold-formed channel columns. Hence the model was used for an extensive parametric study of cross-section geometries. The column strengths obtained from the finite element analysis are compared with the design column strengths calculated using the American, Australian/New Zealand, and European specifications for cold-formed steel structures. The fixed-ended columns are designed as concentrically loaded compression members. Design column curves obtained from the three specifications are plotted. It is shown that the design column strengths calculated from the three specifications are generally conservative for lipped channels having a maximum plate thickness of 6.0 mm. The reliability of the column strengths is evaluated using reliability analysis.