Seismic Response Analysis of Nuclear Structure Using Innovative Three-Dimensional Isolation Device
Hao Xu1, Wenguang Liu1, Shaoping Li2, Daoming Zi3, Wenfu He1
1 Department of Civil Engineering, Shanghai University
Shanghai 200444, China
2 Shanghai Nuclear Engineering Research & Design Institute
Shanghai 200233, China
3 Liuzhou Orient Engineering Rubber Products co., LTD
Liuzhou 545005, China
Abstract. In this paper, an innovative 3D oblique sliding friction seismic isolator (3D OSFSI) is introduced in which lead rubber bearings (LRBs) are installed obliquely. A static compression test for a model device comprised of three LRB100 (diameter 100 mm) was conducted. Based on test results, the hysteretic model of 3D OSFSI system with asymmetric characteristic is proposed, in which the post-yielding stiffness in the loading process and unloading process are different, and the vertical hysteretic loop is asymmetrically quadrilateral. Eight ground motions were selected and their spectrum characteristics were examined. Compared to the far-field ground motions, the peak ground accelerations (PGAs) for the vertical component of the near-fault records are normally larger, and their predominant periods are generally shorter. Hence, it is reasonably to conclude that seismic damage is to be dominant for a structure under near-fault pulse-like earthquakes. The design of a typical nuclear power plant (NPP) structure using the proposed 3D isolation technology was completed and the corresponding numerical model was established. Nonlinear time history analysis using Newmark-β method on the 3D-OSFSI-isolated NPP system was then conducted. The results show that the seismic responses of the NPP structure can be efficiently reduced. Also, the numerical results indicate that the angle of inclination and the friction coefficient of the 3D OSFSI have a significant influence on the structural responses.
Keywords: nuclear power plant, static test, 3D seismic isolation, vertical ground motion, earthquake response.
