Comparative Study of Differential Equation of Equilibrium Method and Constrained and Unconstrained Finite-Strip Method–Direct Strength Method for Prediction of Axial Strength of Cold-Formed Steel Sheathed Wall Studs

Abstract

Modified cold-formed steel (CFS) load-bearing wall-panels under consideration consist of a stud (C-section), track (U-section), and sheathing. Self-drilling screws are used to attach sheathing to the CFS frame. It was observed during various experimental testing that the behavior and strength of the CFS wall-stud changes in the presence of sheathing under axial loading. The present paper investigates the efficacy of a handy tool through analytical and semianalytical models, i.e., the differential equation of equilibrium (DEEq) method for a lipped C-section with continuous elastic supports and the constrained and unconstrained finite-strip method–direct strength method (CUFSM-DSM) by obtaining load factors through an elastic buckling analysis carried out using the CUFSM Tool, version 4.05, respectively, for the evaluation of the axial strength of sheathed CFS. In both the methods, the bracing provided by sheathing to the stud is assumed as spring. The predicted results by both methods are compared with observed strengths of short, intermediate, and long sheathed CFS wall-studs from the experimental database. Results demonstrate a good agreement with the experimental results. For the first time, an attempt is made to compare both the mathematical models to predict the axial strength of the CFS walls. The results presented in this paper demonstrate that the semianalytical tool may be used effectively for the design of a load-bearing sheathed-CFS wall panel.