An experimental investigation of distortional buckling of steel storage rack columns

An experimental investigation on the behavior of steel storage rack columns subjected to compression is presented. Members of different lengths are tested, but special attention is focused on the behavior of the specimens having lengths that make them subject to distortional buckling. This mode of buckling can be observed in moderately long specimens; namely, longer than the stub columns used for the determination of the local buckling strength, but short enough to avoid the effects of global buckling. The deformation experienced by these specimens is measured, and it is observed that there is a range of member lengths where the failure mode is a combination of distortional buckling and global buckling modes. Furthermore, it is verified that, although the effect of the interaction between these modes on the member strength is not large, the accuracy of the current design procedures improves if it is considered in the calculations.