Post-northridge Welded Connections to Concrete Filled Steel Tube Columns: An Advancement in Seismic Performance

It is imperative to implement a seismically resistant construction to mitigate the occurrence of casualties resulting from earthquakes, according to post-Northridge research. The beam-to-column connections exhibited a tendency towards brittle failure in the majority of building collapses that occurred after the earthquake. The growing need for resilient buildings along with sustainable buildings necessitates a design that is economically feasible, energy efficient, and reliable while maintaining the structural rigidity of the building. This research paper examines strategies for enhancing the seismic performance of structural connections in civil engineering applications, with a focus on the interface between steel beams and concrete-filled tubular (CFT) columns. The study investigates three connection models: externally reinforced with cover plates, incorporating reduced beam sections, and a combination of both techniques. Finite element analysis under cyclic loading conditions was employed to evaluate the efficacy of these connection designs. Results indicate that the addition of cover plates (RCFT-CP) significantly improves both moment capacity and connection rigidity. Conversely, the implementation of reduced beam sections (RCFT-RBS) leads to a decrease in rigidity but potentially improves overall structural ductility. The study also highlights the inverse relationship between connection rigidity and panel zone performance. Notably, the hybrid approach combining reduced beam sections and cover plates (RCFT-RBSCP) demonstrated superior structural capacity and enhanced seismic response. These findings contribute valuable insights to the ongoing efforts in civil engineering to develop more resilient and seismically robust structural connections, particularly in steel-concrete composite systems.