Behavior of Cold-Formed Steel Wall Stud Assemblies

The overall behavior under axial loading of cold-formed steel wall stud assemblies is investigated. Wall stud assemblies consist of several wall studs acting as beam columns, top and bottom tracks to restrain the ends of the studs, and may include both diaphragm and discrete bracing. Particular emphasis is placed on the study of strengthening effects of channel bridging and strap bracing, effective lengths for buckling of braced and unbraced studs, and loading eccentricity effects on axial strength. Experimental efforts include individual long column testing to study the interaction of local and overall buckling, flat-ended column testing to estimate loading eccentricities for wall studs and tracks bearing directly on concrete floors, and wall stud assembly tests to observe the behavior of the overall system including the effects of commonly used bracing elements. The test results are compared to predictions based on the 1986 American Iron and Steel Institute specification for the design of cold-formed steel wall studs.