Periodic foundations for seismic base isolation of small modular reactors

This paper discusses analytical and experimental studies on three-dimensional (3D) periodic foundations to investigate their seismic performance. The basic theory of 3D periodic foundations is first presented and parametric studies of three-dimensional two-component (3D2C) periodic foundations are reported. Basically, the affecting variables for the optimum low and wide frequency band gaps are investigated. The variables include material properties, geometric arrangements, and number of unit cells. Based on the parametric studies, a test specimen was designed and constructed, which consists of a 3D2C periodic foundation supporting a small modular reactor (SMR) building. A large-scale shake table test was then conducted to validate the capability of the 3D2C periodic foundation to isolate the SMR building. The test results demonstrate that the 3D2C periodic foundation can reduce the acceleration response of superstructure in both the horizontal and vertical directions. Moreover, the displacement response of the structural system was also reduced. The experimentally proven concept to block the seismic waves has made periodic foundations as a potential next generation of seismic base isolators. ? (2018) by Earthquake Engineering Research Institute All rights reserved.