Study on the mechanical characteristics of vertical seismic isolation system employing hydraulic apparatus

Abstract:

To address the limitation that existing seismic isolation devices mainly focus on horizontal directions while providing insufficient vertical control, a novel hydraulic accumulator-based vertical seismic isolation system was proposed to mitigate the vertical seismic response of the structures. The system′s stiffness characteristics were analyzed, followed by experimental validation to assess its mechanical performance and energy dissipation capability. A dynamic model of the isolation system was then established, and the harmonic balance method was employed to determine the system′s amplitude-frequency response and displacement transmissibility. The effects of vibration amplitude, damping ratio, and accumulator volumetric compression coefficient on the displacement transmissibility were analyzed. Finally, finite element models for both the vertical seismic isolation structure and a conventional frame were established and subjected to seismic time history analysis, and the seismic response results of the two frameworks were compared. The analysis results show that the vertical acceleration response of VSI-HCA structures is reduced by an average of 59% compared to the ground input, indicating a significant vertical isolation effect.