Experimental and analytical studies of cold-formed steel sections with edge-stiffened circular holes subjected to web crippling

Cold-formed steel sections are often used as wall studs or floor joists and such sections often include web holes for ease of installation of services. The holes are normally punched or bored and are unstiffened; when the holes are near to points of concentrated load, web crippling can be the critical design consideration. Recently, a new generation of cold-formed steel channel sections with edge-stiffened circular holes has been developed. The web holes are stiffened through a continuous edge stiffener/lip around the perimeter of the hole. In this paper, a combination of experimental investigations and non-linear finite element analyses are used to investigate the effect of such edge-stiffened holes under the interior-one-flange (IOF) and end-one-flange (EOF) loading conditions; for comparison, sections without holes and with unstiffened holes are also be considered. A non-linear finite element models are described, and the results compared against the laboratory test results; a good agreement was obtained in terms of both strength and failure modes.