scholarly journals Application of Seismic Isolation to the STAR-LM Reactor

2002 ◽  
Author(s):  
B. Yoo ◽  
R. F. Kulak
Keyword(s):  
Seismic Isolation ◽  
Design Research ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Base System ◽  
Two Dimensional ◽  
Isolation System ◽  
Fixed Base ◽  
Initial Work ◽  
Isolation Systems

This paper presents findings from our initial work in developing a seismic isolation system for the STAR-LM reactor design. Research and development was carried out to determine the characteristics of the isolator device. The heavy weight and small footprint presented a challenge in bearing design and bearing placement. Results are also presented from a study on the use of three-dimensional seismic isolation devices to the full-scale reactor. Both two-dimensional (i.e., one device for horizontal isolation only) and integral (i.e., one device for horizontal and vertical) concepts were explored. The seismic analysis responses of the two-dimensional and the three-dimensional isolation systems for the STAR-LM are compared with that of the conventional fixed base system. Finally, results are presented from a study on the effects of the levels of vertical and horizontal damping on the seismic response of STAR-LM.

Seismic Analysis and Comparison of Different Base Isolation Systems for a Multi-Storey RC Building with Irregularities in Plan

2012 ◽  
Vol 594-597 ◽  
pp. 1788-1799 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis
Keyword(s):  
Base Isolation ◽  
Seismic Analysis ◽  
Cyclic Behavior ◽  
Isolation System ◽  
High Damping Rubber Bearings ◽  
Fixed Base ◽  
Base Isolation System ◽  
High Damping Rubber ◽  
Isolation Systems ◽  
Rubber Bearings

In the present paper the dynamic nonlinear analysis for a 3D base isolated structure is illustrated. A base isolated reinforced concrete building is designed and verified according to the European seismic codes such that the superstructure remains almost completely elastic and the nonlinear elements are localized only in the base isolation system. Nonlinear hysteretic models have been adopted to reproduce the cyclic behavior of the isolators. Two different base isolation systems are considered and their performances are compared for evaluating the behaviour of a base isolated building, highly irregular in plan, in presence of a seismic excitation defined with recorded accelerograms which characterize the bi-directional ground motions. The isolation system has been realized with a combination in parallel of elastomeric bearings and sliding devices. In the first analyzed isolation system we have used the High Damping Rubber Bearings (HDRB) and in the second analyzed isolation system we have used the Lead Rubber Bearings (LRB). Finally a comparative analysis between the base isolated structure with hybrid base isolation systems and the conventional fixed base structure is detailed.

Research and Development of Three Dimensional Seismic Isolation System Utilized Coned-Disc-Springs With Rubber Bearings

2017 ◽  
Author(s):  
Takayuki Miyagawa ◽  
Tomoyoshi Watakabe ◽  
Tomohiko Yamamoto ◽  
Tsuyoshi Fukasawa ◽  
Shigeki Okamura
Keyword(s):  
Seismic Isolation ◽  
Three Dimensional ◽  
Safety Margin ◽  
Seismic Load ◽  
Isolation System ◽  
Seismic Safety ◽  
Track Record ◽  
Rocking Motion ◽  
Isolation Systems ◽  
Rubber Bearings

The seismic isolation system consisting of laminated rubber bearings is applied to development of the Sodium-cooled Fast Reactor (SFR) in Japan. While rubber bearings as horizontal isolation system have been expected to be ensured seismic safety margin of components installed in reactor building against horizontal seismic load, vertical isolation systems have been also studied in order to tolerate to the seismic load which has been increased steadily. In this paper, the three dimensional seismic isolation system by combining coned disc springs with rubber bearings is proposed as a concept which consists of isolation devices with abundant track record. Analytical study for this system results that the rocking motion can be suppressed by itself without any suppression system and that the mitigation of vertical response can be enough for buckling design of the reactor vessel simultaneously. In particular, it is important that the vertical natural frequency of system is within the range of 3Hz to 5Hz. Besides, layout, size and stacks of coned discs in the unit of system are studied in order to obtain suitable for specification to SFR buildings.

Required Properties of Seismic Isolation System for Nuclear Power Plants

2010 ◽  
Author(s):  
Satoshi Fujita ◽  
Keisuke Minagawa ◽  
Takeshi Kodaira
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Three Dimensional ◽  
Isolation System ◽  
Seismic Safety ◽  
Isolation Systems ◽  
Rubber Bearings ◽  
Seismic Isolation Systems

In Japan, applications of seismic isolation systems to new generation nuclear power plants and fast breeder reactors have been expected in order to enhance seismic safety. However there are lots of restrictions for design of isolation systems, such as strong design seismic wave, deformation of piping between an isolated structure and a non-isolated structure, and so on. In addition combination of horizontal and vertical isolation has possibility to cause rocking motion if a three-dimensional isolation system is applied. Therefore isolation systems should be designed properly. Moreover the design of seismic isolation system has to consider influence on inner equipment and piping. This paper describes investigation regarding required properties and performance of seismic isolation system for nuclear power plants. The investigation is carried out by numerical analysis. In the analysis, various isolation devices such as friction pendulum bearings and so on are applied as well as natural rubber bearings.

Isolation Performance of Intelligent Seismic Isolation System Using Air Bearing

2009 ◽  
Author(s):  
Satoshi Fujita ◽  
Keisuke Minagawa ◽  
Mitsuru Miyazaki ◽  
Go Tanaka ◽  
Toshio Omi ◽  
...  
Keyword(s):  
Seismic Isolation ◽  
Seismic Waves ◽  
Three Dimensional ◽  
Vertical Motion ◽  
Air Bearings ◽  
Natural Period ◽  
Isolation System ◽  
Vertical Excitation ◽  
Long Period ◽  
Isolation Performance

This paper describes three-dimensional isolation performance of seismic isolation system using air bearings. Long period seismic waves having predominant period of from a few seconds to a few ten seconds have recently been observed in various earthquakes. Also resonances of high-rise buildings and sloshing of petroleum tanks in consequence of long period seismic waves have been reported. Therefore the isolation systems having very long natural period or no natural period are required. In a previous paper [1], we proposed an isolation system having no natural period by using air bearings. Additionally we have already reported an introduction of the system, and have investigated horizontal motion during earthquake in the previous paper. It was confirmed by horizontal vibration experiment and simulation in the previous paper that the proposed system had good performance of isolation. However vertical motion should be investigated, because vertical motion varies horizontal frictional force. Therefore this paper describes investigation regarding vertical motion of the proposed system by experiment. At first, a vertical excitation test of the system is carried out so as to investigate vertical dynamic property. Then a three-dimensional vibration test using seismic waves is carried out so as to investigate performance of isolation against three-dimensional seismic waves.

Dynamic Nonlinear Analysis of an Hybrid Base Isolation System with Viscous Dampers and Friction Sliders in Parallel

2012 ◽  
Vol 234 ◽  
pp. 96-101 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis
Keyword(s):  
Nonlinear Analysis ◽  
Base Isolation ◽  
Three Dimensional ◽  
Time History ◽  
Seismic Action ◽  
Viscous Dampers ◽  
Isolation System ◽  
Fixed Base ◽  
Base Isolation System ◽  
Dynamic Nonlinear Analysis

In the present work we have analyzed a particular base isolation system for the seismic protection of a multi-storey reinforced concrete (RC) building. The viscous dampers and friction sliders are the devices adopted in parallel for realizing the base isolation system. The base isolation structure has been designed and verified according to European seismic code EC8 and by considering for the friction sliders the influence of the sliding velocity on the value of the friction coefficient. A dynamic nonlinear analysis for a three-dimensional base isolated structure has been performed. Recorded accelerograms for bi-directional ground motions have been used which comply with the requirements imposed by EC8 for the representation of a seismic action in a time history analysis. In this paper a comparative analysis is presented between the base isolated structure with the described hybrid base isolation system and the traditional fixed base structure.

Three Dimensional Seismic Isolation System Using Hydraulic Cylinder

2002 ◽  
Author(s):  
Shinichiro Kajii ◽  
Naoki Sawa ◽  
Nobuhiro Kunitake ◽  
K. Umeki
Keyword(s):  
Seismic Isolation ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Hydraulic Cylinder ◽  
Seismic Load ◽  
3D Seismic ◽  
Isolation System ◽  
Response Characteristics ◽  
Seismic Motion ◽  
Hydraulic Cylinders

A three-dimensional (3D) seismic isolation system for FBR building is under development. The proposed vertical isolation system consists form hydraulic cylinders with water-based liquid and accumulators to support large vertical static load and to realize low natural frequency in the vertical direction. For horizontal isolation, laminated rubber isolator or sliding type isolator will be combined. Because the major part of the feasibility of this isolation system depends on the sealing function and durability of the hydraulic cylinder, a series of feasibility tests of the hydraulic cylinder have been conducted to verify the reliability against seismic load and seismic motion. This paper describes the specification of the seismic isolations system, seismic response characteristics and the results of the feasibility tests of the seal. This study was performed as part of a government sponsored R&D project on 3D seismic isolation.

Study on Three-Dimensional Seismic Isolation System for Next Generation Nuclear Power Plant: Independent Cable Reinforced Rolling-Seal Air Spring

2004 ◽  
Author(s):  
Mitsuru Kageyama ◽  
Yoshihiko Hino ◽  
Satoshi Moro
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
Outer Diameter ◽  
Next Generation ◽  
Air Spring ◽  
Isolation System ◽  
Rubber Sheet

In Japan, the development of the next generation NPP has been conducted in recent years. In the equipment/piping design of the plant, seismic condition has been required much more mitigate than before. So, the three-dimensional (abbreviation to 3D) seismic isolation system development has also been conducted since 2000. The superlative 3D base isolation system for the entire building was proposed. The system is composed of cable reinforced air springs, rocking arresters and viscous dampers. Dimensions of the air spring applied to the actual power plant are 8 meters in the outer-diameter and 3.5 meters in height. The allowable half strokes are 1.0 meters in horizontal and 0.5 meters in vertical respectively. The maximum supporting weight for a single device is 70 MN. The inner design air pressure is about 1.8MPa. This air spring has a distinguishing feature, which realizes 3D base isolation with a single device, whose natural periods are about 4 seconds in horizontal and about 3 seconds in vertical. In order to verify the 3D performance of this system, several feasibility tests were conducted. Firstly, 3D shaking table tests were conducted. The test specimen is scaled 1/4 of the actual device. The outer diameter and inner air pressure of air spring is 2 meters and 0.164 MPa. Next, a pressure resistant test for the sub cable, textile sheet and rubber sheet, which composed air spring, were conducted as a full scale model test. Then, air permeation test for the rubber sheet was also conducted. As a result, the proposed system was verified that it could be applied to the actual nuclear power plants.

Seismic Isolation Analysis on Long-Span Platform Bridge Connecting Twin-Tower Structures

2011 ◽  
Vol 255-260 ◽  
pp. 1225-1229
Author(s):  
Huang Sheng Sun ◽  
Li Nuo Cheng ◽  
Shi Hai Chen
Keyword(s):  
Seismic Isolation ◽  
Seismic Responses ◽  
One Pot ◽  
Isolation System ◽  
High Position ◽  
Long Span ◽  
Steel Truss ◽  
Story Drift ◽  
Isolation Systems ◽  
Rubber Bearings

In order to mitigate the seismic response of twin-tower structure linked by a steel truss platform bridge, as well as to reduce temperature force in the steel truss, eight groups of combined isolation system, each consisting of one pot-type bearing and four rubber bearings, were designed to connect the upper platform bridge to the lower supporting reinforced concrete towers. The features and working principles of the high-position isolation system were described. Then the seismic responses, including displacement, story drift and floor acceleration, of the structure with the isolation systems were calculated and compared with those of the structure with hinge joints in lieu of isolation. It is found that both the structural seismic responses and the temperature forces in the large-span mega-truss structure can be reduced by the high-position isolation system.

scholarly journals A liquid spring–magnetorheological damper system under combined axial and shear loading for three-dimensional seismic isolation of structures

2018 ◽  
Vol 29 (18) ◽  
pp. 3517-3532 ◽  
Author(s):  
Sevki Cesmeci ◽  
Faramarz Gordaninejad ◽  
Keri L Ryan ◽  
Walaa Eltahawy
Keyword(s):  
Seismic Isolation ◽  
Theoretical Calculations ◽  
Three Dimensional ◽  
Real Life ◽  
Vertical Component ◽  
Axial Loading ◽  
Shear Loading ◽  
Magnetorheological Damper ◽  
Isolation System ◽  
Fail Safe

This study focuses on experimental investigation of a fail-safe, bi-linear, liquid spring magnetorheological damper system for a three-dimensional earthquake isolation system. The device combines the controllable magnetorheological damping, fail-safe viscous damping, and liquid spring features in a single unit serving as the vertical component of a building isolation system. The bi-linear liquid spring feature provides two different stiffnesses in compression and rebound modes. The higher stiffness in the rebound mode prevents a possible overturning of the structure during rocking mode. For practical application, the device is to be stacked together along with the traditional elastomeric bearings that are currently used to absorb the horizontal ground excitations. An experimental setup is designed to reflect the real-life loading conditions. The 1/4th-scale device is exposed to combined dynamic axial loading (reflecting vertical seismic excitation) and constant shear force that are up to 245 and 28 kN, respectively. The results demonstrate that the device performs successfully under the combined axial and shear loadings and compare well with the theoretical calculations.

Three Dimensional Seismic Isolation System for Next-Generation Nuclear Power Plant With Rolling Seal Type Air Spring and Hydraulic Rocking Suppression System

2005 ◽  
Author(s):  
Takahiro Shimada ◽  
Junji Suhara ◽  
Kazuhiko Inoue
Keyword(s):  
Dynamic Loading ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
Loading Test ◽  
Isolation System ◽  
Ability Test ◽  
Base Isolation System ◽  
Suppression System

Three dimensional (3D) seismic isolation devices have been developed to use for the base isolation system of the heavy building like a nuclear reactor building. The developed seismic isolation system is composed of rolling seal type air springs and the hydraulic type springs with rocking suppression system for vertical base isolation device. In horizontal direction, the same laminated rubber bearings are used as horizontal isolation device for these systems. The performances and the applicability have already been evaluated by the technical feasibility tests and performance tests for each system. In this study, it was evaluated that the performance of the 3D base isolation system with rolling seal type air springs combined with hydraulic rocking suppression devices. A 1/7 scaled model of the 3D base isolation devices were manufactured and some performance test were executed for each device. For the rolling seal type air springs, dynamic loading test was executed with a vibration table, and pressure resistant ability test was executed for reinforced air springs. In the dynamic loading test, it is confirmed that the natural period and damping performance were verified. In the pressure resistant ability test, it is confirmed that the air springs had sufficient strength. For the hydraulic rocking suppression system, forced dynamic loading test was carried out in order to measure the frictional and oil flow resistance force on each cylinder. And the vibration table tests were carried out with supported weight of 228 MN in order to evaluate and to confirm the horizontal and vertical isolation performance, rocking suppression performance, and the applicability of the this seismic isolation system as the combined system. 4 rolling seal type air springs and 4 hydraulic load-carrying cylinders with rocking suppression devices supported the weight. As a result, the proposed system was verified that it could be applied to the actual nuclear power plant building to be target.

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