Behaviour of cold-formed steel perforated sections in compression. Part 1—Experimental investigations

This paper is the first part of a study devoted to interactive buckling of steel pallet racks compression members, carried out at the CEMSIG Research Centre 〈http://cemsig.ct.upt.ro〉 from “Politehnica” University of Timisoara; this part summarizes the experimental program [1] and [2]. Upright members of two different cross-sections, with and without perforations, were tested according to the guidelines of European design code for pallet rack systems EN15512 [3], in order to determine the ultimate strength for specimens of length corresponding to local buckling, i.e. stub columns, and of length equal to the distance between two subsequent nodes of an upright frame, i.e. upright members. The last set of tests was devoted, mainly, to the observation of distortional buckling of upright members. However, depending on the cross-section dimensions, the length between two subsequent nodes can be often larger than distortional critical length. In such cases the test results correspond rather to the distortional–global interaction, than to pure distortion. Consequently, additional specimens having the length calibrated to correspond to distortional buckling and to interactive distortional-overall buckling range, respectively, were tested. Material tests and imperfection measurements were also performed.

► Pallet rack upright specimens of two different cross-sections, with and without perforations, were tested according to EN15512.
► Additionally, specimens with lengths calibrated for pure distortional buckling mode have been tested too.
► Material properties, residual stresses and geometrical imperfections have been measured.
► Interpretation of results related to the buckling behavior of tested members enabled to evaluate the erosion of theoretical buckling strength and, on this basis, to calibrate the imperfection factors to be used into the European buckling curves.
► It is proved that, for such type of section, the perforations could be considered as an imperfection.