Experimental Investigation of the Web Crippling Behaviour of Curved Cold-Formed Steel Unlipped Channel Beams

Cold-Formed Steel (CFS) channel sections have gained significant attention in the construction industry due to their inherent characteristics. With the increasing popularity of curved structures in architectural and structural designs, understanding the structural performance of curved CFS elements is important. This study investigates the web crippling behaviour of curved CFS unlipped channel beams. Through a series of experimental tests conducted under interior two-flange loading conditions, the research evaluated the resistance of these beams to web crippling. The beams with different curvatures, including both flanges inward and outward-curved were systematically analysed to understand their impact on web crippling resistance. The findings indicate that the web crippling capacity is significantly affected by the initial curvature. Notably, the flange inward curvature enhances the web crippling capacity, whereas the flange outward curvature diminishes it compared to straight, unlipped channel sections. Furthermore, the design guidelines commonly used for predicting web crippling capacity were evaluated for consistency and reliability compared to the experimental results. The study concludes by outlining the inconsistencies of using the guidelines developed for straight beams in evaluating the web crippling capacities of curved CFS unlipped channel sections.