Experimental Evidence of Erosion of Critical Load in Interactive Buckling

The paper starts with a selective review of some basic contributions related to local-overall buckling mode interactions in thin-walled steel members. Then, the results of an intensive experimental study carried out at the Politehnica University of Timisoara with the purpose of evaluating the erosion of a theoretical bifurcation load in the distortional-flexural buckling interaction range in pallet rack uprights are presented. Two different sizes of cross sections, with and without perforations, have been studied. To evaluate and quantify the erosion, the erosion of the critical bifurcation load approach is applied. This approach enables one to use the European buckling curves in the Ayrton-Perry format, expressing the imperfection factor (alpha) in terms of the erosion coefficient (psi). It allows estimation of the member's ultimate capacity, taking into account the interaction of sectional (local or distortional) and member (flexural, torsional, or flexural-torsional) instability modes. Test results and the evaluation procedure for the erosion coefficient (psi) and imperfection factor (alpha), applied on tested specimens, are presented. DOI: 10.1061/(ASCE)ST.1943-541X.0000789. (C) 2013 American Society of Civil Engineers.