Abstract

The new Structural Seismic Isolation System (SSIS) intends to provide high safety for important structures such as nuclear power plants, offshore oil platforms, and high-rise buildings against near-fault and long-period earthquakes. The presented SSIS structure foot base and foundation contact surfaces have been designed as any curved surfaces (spherical, elliptical, etc.) depending on the earthquake-soil-superstructure parameters, and these contact surfaces have been separated by using elastomeric (lead core rubber or laminated rubber bearings with up to 4-second period) seismic isolation devices. It would allow providing inverse pendulum behavior to the structure. As a result of this behavior, the natural period of the structure will possess greater intervals which are larger than the predominant period of the majority of the possible earthquakes including near-fault zones. Consequently, the structure can maintain its serviceability after the occurrence of strong and long-period earthquakes. This study has investigated the performance of the SSIS for the nuclear containment (SSIS-NC) structure. The finite element model of SISS-NC structure has been developed, and nonlinear dynamic analysis of the model has been conducted under the strong and long-period ground motions. The results have been presented in comparison with the conventional application method of the seismic base isolation devices for nuclear containment (CAMSBID-NC) and fixed base nuclear containment (FB-NC) structures. The base and top accelerations, effective stress, and critical shear stress responses of the SSIS-NC structure are 48.67%, 36.70%, and 32.60% on average lower than those of CAMSBID-NC structure, respectively. The result also confirms that the SSIS-NC structure did not cause resonant vibrations under long-period earthquakes. On the other hand, there is excessive deformation in the isolation layers of CAMSBID-NC structure.

Highlights

  • Seismic base isolation is indicated as a reliable tool for the protection of structures against strong earthquakes [1, 2], and there are more than seven thousand seismically isolated buildings around the world

  • All are pressurized water reactors (PWR), four of them located in Cruas Meysse (France) and the remaining two in Koeberg (South Africa) [3]. e main reasons for limited usage of seismic isolation are related to decline of nuclear power plant construction from 1980 to 2010, construction of NPPs in regions with low seismic hazard risks, and lack of proper codes/standards for the design of

  • Fundamentals of Seismic Isolation System (SSIS). e main aim of the SSIS is to keep the period of structure beyond the period of the earthquake. is aim is approached by building structure foot base, and foundation contact surfaces have been designed as any curved surface depending on the earthquake-soil-superstructure parameters and these contact surfaces have been separated by using elastomeric seismic isolation devices

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Summary

New Structural Seismic Isolation for Nuclear Containment Structures

E new Structural Seismic Isolation System (SSIS) intends to provide high safety for important structures such as nuclear power plants, offshore oil platforms, and high-rise buildings against near-fault and long-period earthquakes. e presented SSIS structure foot base and foundation contact surfaces have been designed as any curved surfaces (spherical, elliptical, etc.) depending on the earthquake-soil-superstructure parameters, and these contact surfaces have been separated by using elastomeric (lead core rubber or laminated rubber bearings with up to 4-second period) seismic isolation devices. E presented SSIS structure foot base and foundation contact surfaces have been designed as any curved surfaces (spherical, elliptical, etc.) depending on the earthquake-soil-superstructure parameters, and these contact surfaces have been separated by using elastomeric (lead core rubber or laminated rubber bearings with up to 4-second period) seismic isolation devices. E new Structural Seismic Isolation System (SSIS) intends to provide high safety for important structures such as nuclear power plants, offshore oil platforms, and high-rise buildings against near-fault and long-period earthquakes. It would allow providing inverse pendulum behavior to the structure. There is excessive deformation in the isolation layers of CAMSBID-NC structure

Introduction
Seismic isolators
Lower spherical foundation
Total superstructure Total structure
Long period
El Mayor
Full Text
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