Experimental study on strengthening CFS dry joints in existing racking systems

This paper presents preliminary results from an ongoing experimental campaign investigating the effectiveness of different reinforcement systems for dry joints in cold-formed steel rack structures, with a focus on their down-aisle seismic behavior. The new Italian regulations for existing CFS rack structures require end users to verify the seismic response of their racking systems and, in case the safety level is not adequate, to implement reinforcement measures. Accordingly, this study evaluates practical reinforcement solutions aimed at enhancing structural resilience. A series of monotonic and cyclic tests were performed on full-scale specimens, considering both unreinforced and reinforced dry joints. Reinforcement systems, including the use of additional bolts, U-shaped reinforcement brackets, and innovative connection detailing, were investigated. Experimental results demonstrate improvements in stiffness, ductility, and overall cyclic performance of reinforced joints compared to unreinforced ones. Particular attention is given to energy dissipation capacity, deformation mechanisms, and failure modes under cyclic loading. Findings not only provide useful indications for the reinforcement of dry joints in existing racking systems but also contribute to improving the understanding of their seismic behavior and provide valuable insights for structural engineers aiming to improve the safety and reliability of storage systems in seismic regions.