Finite Element Analytical Investigation of Torsional Bracing Requirements for Cold-formed Steel C-shaped Studs

This paper provides an overview of an investigation on the torsional bracing behavior of C-shaped cold-formed steel studs. Typical bracing details for the Cshaped studs consist of a steel channel that restrains twist of the cross section. Three-dimensional finite element models were used to investigate the stiffness behavior for stability braces used to improve the torsional buckling performance of the studs. The lipped C-shaped section was modeled with pin-ended boundary conditions for the stud. Multiple models of the torsional brace were evaluated including a shell element model of a bracing channel as well as several “simpler” spring configurations. The development of these models and appropriate modeling techniques for bracing is discussed in detail. Difficulties in capturing the distortional behavior in the thin walled stud are discussed. Results from eigenvalue buckling solutions are presented. Recommendations are made for extending the use of these models to a broader range of stud sizes and analysis types to obtain recommendations for torsional bracing requirements of typical cold-formed wall studs. 1 Structural Engineer, Schwab Structural Engineering, Inc., 555 IH 35 South, Suite 230, New Braunfels, TX 78130 2 Assistant Professor, Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, 1 University Station C1748, Austin, TX 78712-0273 3 Senior Lecturer, Department of Civil and Coastal Engineering, 365 Weil Hall, University of Florida, Gainesville, FL 32611 (email: sputo@ufl.edu)