Research and development of three-dimensional isolation system for sodium cooled fast reactor, 9; Evaluating seismic isolation performance through seismic response analysis

深沢 剛司*; 杣木 孝裕*; 湯川 正貴*; 平山 智之*; 渡壁 智祥; 山本 智彦  ; 岡村 茂樹; 宮崎 真之; 内田 昌人*; 宮川 高行; 藤田 聡*

Fukasawa, Tsuyoshi*; Somaki, Takahiro*; Yukawa, Masaki*; Hirayama, Tomoyuki*; Watakabe, Tomoyoshi; Yamamoto, Tomohiko; Okamura, Shigeki; Miyazaki, Masashi; Uchita, Masato*; Miyagawa, Takayuki; Fujita, Satoshi*

This paper elucidates the isolation performance of a newly developed three-dimensional seismic isolation system through seismic response analysis. A novel three-dimensional isolation system was developed and assessed through static loading tests, aiming to unveil the hysteresis loops for each element, labeled Part 1 to Part 6. To ascertain the design feasibility of the isolation system, static loading tests were judiciously conducted, considering a wide array of loading conditions, including the beyond-design basis ground motion. Employing the accumulated test data, a new analytical model was devised, capable of precisely capturing the hysteresis loops for each element. Evaluating the seismic isolation performance based on the static loading results of the entire system posed a notable challenge. Nevertheless, the hysteresis characteristics of the overall system in both horizontal and vertical directions were elucidated using a static loading test with a half-scale model, as detailed in Part 7 and Part 8. The authors conducted a seismic response analysis, leveraging the analytical models identified by the static loading test results obtained from the half-scale model. This paper demonstrates that our isolation system exhibits superior isolation performance against both the design basis and beyond-design basis ground motions when compared to a horizontal isolation system consisting of rubber bearings and oil dampers.