The effects of end conditions on the load capacity of cold-formed steel column members of lipped channel cross-section with perforations subjected to compression loading

The effects of end boundary conditions on the compressive load carrying capacity of cold-formed lipped channel sections with perforations are investigated and discussed. Most structural cold-formed steel members are typically manufactured with perforations. These perforations are pre-cut to accommodate electrical, plumbing, and heating services and so on. Due to the size, shape, and position of perforations and end conditions, ultimate strength and elastic stiffness of a structural member can be varied. This paper describes the ultimate strength results obtained from numerical, experimental, and theoretical investigations for two types of end conditions namely, flat-end and fixed-fixed. The numerical results given have been obtained using the ANSYS FEA software package. An experimental study of the buckling behaviour of lipped channel columns of same cross-section, but with different perforation shapes and end conditions is reported and the findings from this are used to validate numerical results; good correlation was obtained both with ultimate strength and failure modes. Further, the study showed that there are similar ultimate load values for corresponding compression members under flat-end and fixed-fixed end conditions, and in general, more conservative estimates of design rule predictions: AISI Specification, British Standard - BS 5950 Part 5, and Eurocode 3.