A theoretical and experimental investigation into cold-formed channel sections in bending with the unstiffened flanges in compression

Twenty-six cold-formed channel sections were tested in four point bending with the unstiffened flanges in compression. The width/thickness ratio for the web varied from 18.8 to 188 and the width/thickness ratio for the flange varied from 3 to 91.75. Post-buckling theories were derived using yield line theory considering both simply-supported and partially fixed boundaries to predict ultimate moment capacity and resulting midspan deflections. Good correspondence was observed between theory and experiment. The use of the Mathcad symbolic algebra package is described in the production of moment-curvature relationships.