Experimental and numerical study on the seismic behavior of RC frame with energy dissipation self-centering hinge joints

Conventional reinforced concrete joints dissipate seismic energy through the deformation of plastic hinges, resulting in excessive residual deformation and difficult-to-repair damage. This paper proposes a new beamcolumn joint type: an Energy Dissipating Self-Centering Hinge Joint (EDSCHJ) with a high-stiffness spring and replaceable dampers fixed at the joint zone. The high stiffness spring provides restoring forces, and the replaceable dampers are utilized to dissipate seismic energy. A quasi-static test was conducted to investigate the seismic performance of the EDSCHJ. Three types of self-centering hinge joints with different dampers are designed and tested, and the hysteretic response, skeleton curve, stiffness degradation curve, and equivalent viscous damping coefficient of the EDSCHJ were obtained. The test results show that the specimens are undamaged at a story drift of 5%, the EDSCHJ without damper exhibits excellent self-centering capability with only a small residual deformation, the hysteresis curve of the EDSCHJ with dampers exhibits a full hysteresis loop with good energy dissipation capacity, the high-stiffness spring has remained elastic without strength degradation, and the lateral stiffness derived from the skeleton curve aligns closely with theoretical calculations. Finally, the finite element model of EDSCHJ is established and validated by comparing the test and numerical results. The structural parametric analysis reveals that as the relative lateral stiffness increases, the dynamic responses of the structure with EDSCHJ exhibits a increasing trend in displacement and an decreasing trend in acceleration and base shear. Additionally, the simulation results indicate an optimum relative stiffness ratio ranging from approximately 0.09 to 0.61.