Web crippling tests of cold-formed steel channels with staggered web perforations

Cold-formed steel studs and purlins with slotted webs including staggered perforations are used in building construction to enhance the thermal performance and energy efficiency of buildings. However, the web perforations adversely affect their structural capacities, especially their shear and web crippling capacities. Limited research has been reported on this subject despite its importance and continuing use of channel sections with staggered web perforations. Hence a series of web crippling tests was undertaken to investigate the web crippling behaviour and capacities of cold-formed steel channels with staggered web perforations under two flange load cases with their flanges unfastened to the supports. Forty eight lipped channel specimens with perforated and solid webs were tested to failure. Comparison of the experimental web crippling capacities of slotted and solid channels showed that the presence of staggered web perforations significantly reduced the web crippling capacities of channel sections. New web crippling capacity design equations are proposed to calculate the reduced web crippling capacities of lipped channel sections with staggered web perforations. This paper presents the details and results of this experimental investigation.