Performance improvement of base-isolated structures by the tuned negative stiffness-inertial mass damper

To control the displacement of the base isolation layer and further enhance the seismic performance of the base-isolated structure (BIS), integrating the advantages of the negative stiffness and tuned viscous mass damper for earthquake protection, the performance enhancement and optimum design of BIS by the tuned negative stiffness-inertial mass damper (TNSIMD) were investigated. Based on the simplified analysis model of BIS, the damping enhancement equation and energy balance equation of the BIS-TNSIMD system were derived. The effects of the parameters of the TNSIMD on the displacement of the base isolation layer, equivalent damping ratio of the BIS, and energy dissipation ratio of the TNSIMD were evaluated. On this basis, a collaborative optimization design method was developed to balance the control performance and design cost. The control performance of the TNSIMD was evaluated when the BIS was subjected to near-field pulse earthquakes through a five-story frame structure. The results show that the TNSIMD takes advantages of its tuned effect and negative stiffness to achieve the energy dissipation improvement and control performance enhancement of the BIS. When the BIS is subjected to the near-field pulse earthquakes, the TNSIMD is more effective than the viscous damper, tuned viscous mass damper, and negative stiffness-inertial mass damper in reducing the displacement and absolute acceleration of BIS, and can dissipate more seismic energy. © 2023 Southeast University. All rights reserved.