Experimental study on web crippling of lapped cold-formed steel channels subjected to interior two-flange loading

The current North American Specifications for the Design of Cold-Formed Steel (CFS) Structural Members, AISI-S136-01, specifies expressions for web crippling strength of different joist geometries in case of exterior end and concentrated load locations. However, it does not permit an in increase two-flange loading. Thus, the objective of this research in this thesis is to generate experimental data for CFS channels where both webs of channel members are lapped at the interior support location and being loaded simultaneously. This thesis summarizes the results of a parametric study to examine few parameters that affect web crippling strength of such lapped channels. These parameters include the unbraced length of channel member, the presence screws, the level of flange restraint at the interior support location, channel six and load bearing length (i.e. lap length). Test specimens were loaded to failure and load history and the failure pattern were recorded. Based on experimental findings, a reliable and economical design expression was developed for web crippling strength of lapped CFS channels at interior support location when subjected to two-flange loading.