Experimental study of earthquake-resilient PBCSC with double flange cover plates

Prefabricated steel structure systems have become new trends in the development of steel structures. Meanwhile, earthquake-resilient steel structures have also become a hot issue in structural seismic performance research. Based on the idea of damage control, this study proposes a new type of earthquake-resilient prefabricated beam-column steel connection (PBCSC), which is formed by a circular tube steel column with a cantilever beam, an independent beam segment, and a connection component. The thickness of the flange cover plates, distance between bolts, and some other parameters could be adjusted suitably to obtain a proper connection stiffness so that sliding of the bolts and plastic deformation of the flange cover plates could dissipate energy and prevent the beam and column from plastic collapse. Quasi-static tests, tests of repaired connections, and fatigue tests were performed on six specimens. The influences of several factors, such as thickness of the cantilever beam flange, weakened form of the flange cover plate, retrofit by adding brass friction plates, and repair after earthquake, were investigated to assess the seismic behaviour of the connection. The experimental results showed that the new type of PBCSC could dissipate energy through the plastic deformation and slip friction of the flange cover plate. The plastic damage of the PBCSC was mainly concentrated in the replaceable plates, which was beneficial to the earthquake resilience of the connection. The bearing capacity and the energy dissipation capacity of the connections remained stable after repair. The stable performance of the connection under low-cycle fatigue load showed that it could be used as a displacement-control damper.