Application of direct strength method to axially loaded perforated cold-formed steel studs: Longwave buckling

A study to develop methods of analyzing perforated, axially loaded, cold-formed steel studs using the provisions of the Direct Strength Method 3] was undertaken using the Finite Strip Method as the method for determining the elastic buckling stresses. Several different models were developed to represent the effect of the web perforations. The capacities predicted using the Direct Strength Method for the limit state of longwave buckling were compared to capacities calculated using the equations contained in the AISI Specification 3]. The limit states of local and distortional buckling are considered in a companion paper 12]. The validity of the results is discussed and recommendations are made for the use of the Direct Strength Method for these members.