Recent research advances on the ECBL approach. Part II: interactive buckling of perforated sections

Perforated cold-formed steel sections are often used in civil engineering as structural members for residential buildings and storage racks construction. In the case of buildings the perforations are provided to permit piping and bridging, while for rack systems they allow for simple connections between members. The load bearing capacity of these sections are influenced not only by the local buckling, global buckling and interaction between these two, but also by the reduction of cross-sectional properties due to perforations. Because of the wide variety in the size and configuration of perforations, it is impossible to provide a practical design procedure to calculate the ultimate strength of such a type of sections. The main objective of this paper is to calibrate an effective design width formula for the perforated sections and, using the ECBL approach, to evaluate an equivalent α imperfection factor for European buckling curves, in order to adapt them for sections with different perforation patterns.