Finite-Element Simulation and Design of Cold-Formed Steel Channels Subjected to Web Crippling

Web crippling may occur at the highly concentrated loading or reactions when there is no end stiffener or load stiffener in cold-formed, thin-walled steel members. A nonlinear finite-element analysis is carried out based on a series of laboratory tests on cold-formed steel channels subjected to web crippling under end-one-flange and interior-one-flange loading conditions as specified in the North American and Australian/New Zealand specifications for cold-formed steel structures. Geometric and material nonlinearities were included in the finite-element analysis. The finite-element results demonstrate that the ultimate load-carrying capacity (web crippling strength), web crippling failure modes, and web deformation curves agree well with the tests. The verified finite-element models are then used for an extensive parametric study of different channel dimensions. It is found that the design strengths calculated from the North American Specification are generally unconservative for channel sections with unstiffened flanges having web slenderness ranging from 7.8 to 108.5 subjected to web crippling under the end-one-flange and interior-one-flange loading conditions. Therefore, the updated coefficients of the design formula in the North American Specification and new design formulas are subsequently proposed in this paper. It is demonstrated that the verified finite-element models provide an effective and time efficient means to predict web crippling strengths of cold-formed steel members.