Seismic performance of prefabricated repairable RCS joints with replaceable multi-segment weakened plates

In order to enable the high-efficiency and easy-operation repairment of prefabricated reinforced concrete column-steel beam (RCS) structure after damage, a novel replaceable assembly RCS joint with multi-segment weakened plate (RCS-MWP) is proposed in this research. The design theory, construction, assembly process, replacement of MWP components and repairment after damaged were introduced. This configuration encompasses three sub-specimens: RCS-MWP, RCS-MWP1, and RCS-MWP2, with varying parameters such as pad thickness and number of weakened segments. For RCS-MWP1 and RCS-MWP2, only the energy dissipation components were replaced after the RCS-MWP were tested and damaged. A comparative study was conducted with a traditional RCS joint with a bolt connection (RCS-B). The test results indicated that the damage to the four specimens (RCS-B, RCS-MWP, RCS-MWP1, and RCS-MWP2) was mainly concentrated at the energy dissipation components, while the reinforced concrete (RC) columns and steel beams remained in the elastic stage with minimal damage. By comparing the RCS-MWP, RCS-MWP1, and RCS-MWP2 specimens, it was observed that RCS-MWP and RCS-MWP2 exhibited second-order buckling, which improved the bearing capacity and energy dissipation capacity. The cumulative energy dissipation of specimens with 8 mm pads in the multi-segmental weakened plate assemblies (RCS-MWP1 and RCS-MWP2) increased by 9 % and 59.4 % compared to RCS-MWP with 3 mm pads, providing enhanced nodal energy dissipation. The average positive and negative bearing capacities of RCS-B were 70.6 % higher than those of the RCS-MWP group, which was caused by the low yield stress of multi-segment weakened plates. After eliminating the residual displacement of specimen RCS-MWP, the seismic performance of the RCS-MWP1 and RCS-MWP2 specimens was barely decreased after diagonally replacing the energy dissipation components. This demonstrates the rationality and feasibility of using replaceable MWP components to repair RCS-MWP joints after the earthquake. It should be noted that the residual displacements after unloading resulted in the restoration of the joints more challenging, hence, prestressing to achieve self-centering could be considered as a potential topic for future research. This proves the feasibility of replacing energy-consuming components. •A novel type of prefabricated repairable RCS joints with multi-segment weakened plates was proposed and investigated.•Design theory, construction, assembly pro