EXPERIMENTAL STUDY ON COLD-FORMED STEEL LIPPED CHANNEL COLUMNS UNDERGOING LOCAL-DISTORTIONAL-GLOBAL INTERACTION

Abstract. This paper reports the available results of an ongoing experimental investigation on fixed cold-formed steel lipped channel columns undergoing local-distortional-global mode interaction, i.e., exhibiting nearly coincident local, distortional and global (flexural-torsional) critical buckling loads. After addressing the preliminary buckling analyses, performed to select appropriate column geometries (cross-section dimensions and lengths), a detailed description of the experimental program carried out at COPPE/UFRJ is provided. Next, the most relevant experimental results obtained during the tests are presented and discussed. Finally, the paper closes with some considerations concerning the design of the columns investigated in this work − in particular, the application of the design expressions currently prescribed by the Direct Strength Method is assessed.