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.

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.

Development of Three Dimensional Seismic Isolation Device With Laminated Rubber Bearing and Rolling Seal Type Air Spring

2002 ◽  
Author(s):  
Junji Suhara ◽  
Tadashi Tamura ◽  
Yasuo Okada ◽  
Katsuhiko Umeki
Keyword(s):  
Seismic Isolation ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Horizontal Load ◽  
3D Seismic ◽  
Air Spring ◽  
Ability Test ◽  
Rubber Bearing ◽  
Laminated Rubber Bearing ◽  
Isolation Device

Three dimensional (3D) seismic isolation device has been developed to use for the base isolation system of the heavy building like a nuclear reactor building. The developed device is the 3D seismic isolation device that consists of the laminated rubber bearing as a horizontal isolation device and the rolling seal type air spring as the vertical isolation device in series. In this research, the 3D seismic isolation device reduction model whose scale is 1/10 is made and the workability of the device by the horizontal and vertical dynamic load is examined. Two experiment parameters are considered. One is the case that the structure of the part that the horizontal load and the vertical load contact is pin condition and the other is the case of the roller condition. As a result of the examination, the workability of the vertical direction is confirmed when the horizontal load acts. The pressure resistant ability test for the air spring is performed by the monotonic pressurization. As the result, it is confirmed that pressure resistant ability improved by restricting the side deformation of the air spring and that the material of the existing air spring can withstand high pressure use sufficiently. As the result, it is confirmed that the developed 3D seismic isolation device is applicable to the actual plant.

Three-Dimensional Seismic Isolation Device With Rolling Seal Type Air Spring

2004 ◽  
Author(s):  
Tetsuya Hagiwara ◽  
Junji Suhara ◽  
Satoshi Moro
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
3D Seismic ◽  
Air Spring ◽  
Scaled Model ◽  
Isolation System ◽  
Ability Test ◽  
Rubber Bearing ◽  
Isolation Device

Three dimensional (3D) seismic isolation device has been developed to use for the base isolation system of the heavy building like a nuclear reactor building. The developed device is the 3D seismic isolation device that consists of the laminated rubber bearing as a horizontal isolation device and the rolling seal type air spring as the vertical isolation device in series. As the lead rubber bearing and the air spring are individually widely utilized with the general buildings and industrial structures, their reliability is high. However, when these pieces of equipment are combined, the issues that should be developed arise. The prospect of the technical feasibility of the device has already been acquired by feasibility test. In this study, a 1/12-scaled model of a 3D base isolation device is manufactured and the four tests are carried out. The four tests are dynamic vertical and horizontal test, orifice-damping test, pressure resistant ability test, and accelerated aging test. As the results of the tests, the developed 3D seismic isolation device is confirmed to be applicable to a nuclear power plant.

Development of Three-Dimensional Seismic Isolation Technology for Next Generation Nuclear Power Plant in Japan

2004 ◽  
Author(s):  
K. Inoue ◽  
M. Morishita ◽  
T. Fujita
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
3D Seismic ◽  
Next Generation ◽  
Air Spring ◽  
Isolation System ◽  
Earthquake Loads ◽  
Base Isolation System

Mitigation of earthquake loads by seismic isolation technology is very promising for enhanced safety and economy of the next generation nuclear reactors, through rationalized and simplified design of structures, systems and components. The horizontal base isolation with laminated rubber bearings is a proven technology and its application has been widely spread including nuclear facilities. On the other hand, significantly increased benefit of mitigated seismic loads is expected with three-dimensional (abbreviated 3D) seismic isolation, since the earthquake loads are inherently three-dimensional and the vertical component of the earthquake load sometimes plays an important role in the structural design of reactor components. From these points of view, a research project has been undertaken for the development of 3D seismic isolation technology, under the sponsorship of the Ministry of Economy, Trade and Industry of the Japanese government. It was presented in a former conference that two types of 3D seismic isolation systems were applicable to the next generation nuclear power plants. One is 3D base isolation of a whole nuclear island, and the other is a vertical isolation system for main components with horizontal base isolation system. Among a number of proposed concepts, three were promising ideas for the 3D base isolation system (or device), i.e., “hydraulic 3D base isolation system”, “independent cable reinforced rolling-seal air spring”, and “rolling seal type air spring”. Then the last idea, i.e., “rolling seal type air spring”, was selected from above three ideas for further development. In this paper, current status of this R&D project are firstly shown. Next, the performance requirements for 3D isolation system and devices are shown. Then the developing targets for 3D isolation technology are shown. Furthermore, future plan of the project is provided.

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.

scholarly journals Modeling Study on Stiffness Characteristics of Hydraulic Cylinder under Multi-Factors

2017 ◽  
Vol 63 (7-8) ◽  
pp. 447 ◽  
Author(s):  
Hao Feng ◽  
Qungui Du ◽  
Yuxian Huang ◽  
Yongbin Chi
Keyword(s):  
Mechanical System ◽  
Volume Expansion ◽  
Hydraulic Cylinder ◽  
Experimental Results ◽  
Axial Deformation ◽  
Response Characteristics ◽  
Stiffness Model ◽  
Hydraulic Cylinders ◽  
Stiffness Characteristics ◽  
Cylinder Barrel

For a complex mechanical system driven by hydraulic cylinders, the dynamic response characteristics of the mechanical system are significantly affected by the stiffness characteristics of hydraulic cylinders. This paper comprehensively studies the impacts of various factors on the stiffness characteristics of the hydraulic cylinders, including the oil bulk modulus, the air content in the hydraulic oil, the axial deformation of the piston rod, the volume expansion of the cylinder barrel, the volume expansion of the metal pipes and the flexible hoses, and the deformation of the hydraulic cylinder sealing. By combining the theoretical analysis and the experimental results, the level of each impacting factor was quantified, and the stiffness model of the hydraulic cylinder was established. Finally, comparative analysis of the stiffness was conducted by taking the experimental hydraulic cylinder as an example; it was verified that the calculated results of the proposed hydraulic cylinder stiffness model approximated the experimental results. Compared with stiffness models presented in current literature, the average accuracy was improved by more than 15 %.

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.

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.

Shaking Table Tests With Large Test Specimens of Seismically Isolated FBR Plants: Part 1—Response Behavior of Test Specimen Under Design Ground Motions

2009 ◽  
Author(s):  
Seiji Kitamura ◽  
Masaki Morishita ◽  
Shuichi Yabana ◽  
Kazuta Hirata ◽  
Katsuhiko Umeki
Keyword(s):  
Test Specimen ◽  
Seismic Isolation ◽  
Ground Motions ◽  
Shaking Table ◽  
Scale Model ◽  
Seismic Load ◽  
Response Behavior ◽  
Isolation System ◽  
Seismically Isolated ◽  
Behavior Test

The seismic isolation technology is planned to introduce to the next generation’s fast breeder reactor (FBR) plants in order to reduce seismic load subjected to components. To grasp the ultimate behavior of a seismically isolated plant under extremely strong earthquake at a level beyond the design ground motions and to establish ultimate strength design methods of seismic isolators, we made a series of shaking table test with large test specimen of seismically isolated FBR plants. The ultimate behavior test was performed using one of the world largest three-dimensional shaking tables “E-Defense” of National Research Institute for Earth Science and Disaster Prevention of Japan to obtain ultimate behavior data of a technologically-feasible large scale model. Test specimen consists of concrete blocks, reinforced concrete walls and isolation layer with six laminated rubber bearing with lead plug (LBR). The gross mass of upper structure of the test specimen is about 600ton. The diameter of the LRB is 505mm that reduced prototype dimensions to about 1/3. In this study, the following three behaviors were assumed as the ultimate behavior of the seismic isolation system; 1) loss of response reduction function of the isolation system by hardening of rubber, 2) non-linear response behavior by the cracking of the concrete wall and 3) braking of the LRB. When the input acceleration level increased, the test specimen was designed to show the ultimate behavior in the above-mentioned order. The ultimate behavior test of the seismic isolation system was carried out on the condition of two input waves by using two test specimen sets of the same dimensions. In this paper, details of the test specimen including the LRB and loading conditions are described. Response behavior of the test specimen under design ground motions is also reported. The restoring force characteristics of the LRBs were stable. The response acceleration of a horizontal direction measured at the upper structure of the specimen was reduced. Prior to the ultimate behavior tests with strong input waves, the response reduction functions of the test specimen under design ground motions were confirmed.

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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