The application of the steel sleeve method in steel column-beam connection regions for T-stub connections

Bolted connections are a frequently used method in the beam-to-column joints of steel structures. Particularly after the Northridge earthquake, which marked a turning point for steel connection zones, various connection configurations have been developed to enhance the ductility of beam-to-column joints. This approach, which is one of the energy dissipation methods, involves placing a steel sleeve of specific amplitude and thickness between the flange plate and bolt nut in bolted connections to interrupt the load path at the beam-to-column joint. The analyses in this study were conducted using the finite element method, referencing two studies that experimentally investigated models created with the equivalent T-Stub method recommended in Eurocode-3 for modeling bolted connections. The contribution of the steel sleeve element, placed on the bolt shank in T-Stub connections subjected to axial tensile forces, to energy dissipation and load capacity was analyzed. Significant increases have been achieved in the total elongations of connections and energy dissipation values in these analyses. With the innovative method proposed in this study, the energy dissipation capacity and ductile behavior of bolted connections were significantly improved without negatively affecting their performance in the elastic region. The proposed connection model, when used as a structural damper under seismic effects, will contribute to further improving the structural performance of steel structure joints, particularly in our earthquake-prone country.