Optimum design of cold-formed steel beams subject to bending, shear and web crippling

Recently, cold-formed steel (CFS) members have become more prevalent within the construction industry. CFS beams can be optimised to increase their load carrying capacity. In this research, shape optimisation method is developed to obtain high structural resistance of cold-formed steel beams by taking into account the bending, shear and web crippling actions. First, the flexural strengths of the sections are determined based on the effective width method adopted in EC3, while the optimisation process is performed using the Particle Swarm Optimisation (PSO). Five different CFS channel cross-section are considered in the optimisation process. The flexural strengths of the optimised sections are then verified using detailed nonlinear finite element analysis. The results indicated that the optimised CFS beams provide a bending capacity which is up to 50% higher than the conventional CFS channel sections with the same amount of material. Shear, web crippling behaviours of five optimised
CFS beams were then investigated. Finally, innovative optimised CFS beam was proposed for lightweight forms of buildings and modular building systems to obtain high structural resistance.