Experimental Study of the Bending Performance of Cold-Formed Steel Channel Beams Considering the Corner Hardening Effect

Cold-formed steel channel beam components are increasingly used in lightweight steel buildings owing to the high strength-weight ratio. However, the influence of cold working processes, in relation to corner regions, and how this impacts the bending behavior of channel beams lacks thorough evaluation. In the present study, a series of coupon and bending tests were conducted and the numerical simulation and analytical derivation were supplemented, aiming to investigate the bending performance of cold-formed steel channel beams considering the reinforcement effect in corner regions. The results show that the engineering stress-strain relationships of the flat and corner coupons conformed to the trilinear models with different characteristic parameters. The yielding and ultimate strengths of the corner specimens was increased by 50% and 7%, respectively, compared to the flat coupons due to the cold-bending technique. The strain distribution of the cold-formed channel beams accord with the plane section while the stresses at the corners were 35% higher than those at the flanges, indicting the different mechanical response of the flat and corner regions. The component-based model for cold-formed steel channel beams was established to exactly describe the influence of the cold-bending action, which was greatly validated by the experimental and numerical data with the errors of typical parameters less than 9%.