Research and Development of Three-Dimensional Isolation System for Sodium-Cooled Fast Reactor: Part 6 — Development of High Speed Oil Damper for Isolated Building

Abstract

Abstract The design of seismically isolated structures has been required not only for damping devices with large damping capacities but also for those with high allowable velocities. This is because the seismic response assessment has been conducted using various ground motions, with high acceleration levels, to increase the structural integrity of buildings and components. However, the research focused on increasing the allowable velocity remains to be largely limited because the research involves a testing machine problem as well as a technical problem to increase the allowable velocity. To solve these problems, the authors have developed a new oil damper for seismic isolation buildings with an allowable velocity that is two times higher than commercially available oil dampers, which is the largest damping capacity class in Japan, using the test machine with one of the largest dynamic loading performance in the world. This paper demonstrates the availability of the proposed oil damper through the following items: The first is to clarify the damping force characteristics on the basis of the test results up to the maximum input velocity of 2.7 m/s. The second is to present the analytical model for the oil damper to apply to the seismic response analysis including the method to identify its variables. The third is to demonstrate the isolation performance through the seismic response analysis using the analytical model identified the variables obtained from the test results. These results imply that the proposed oil damper will be able to contribute to expanding the feasible design range for the isolation technology as well as increasing the seismic safety margin of the components for SFR.