Development of three-dimensional seismic isolation system using negative stiffness link mechanism and air levitation mechanism in series (Overview of prototype experimental device and report on full-scale 3-D seismic excitation experiment by E-Defense shaking table)

In Japan, several kinds of three-dimensional seismic isolation system for next-generation nuclear power plant such as fast reactors have been studied in recent years. We proposed a structural concept of a vertical component isolation system, assuming a building adopting a horizontal base isolation system. In this concept, a reactor vessel and major primary components are suspended from a large common deck supported by isolation devices consisting of large coned disk springs. In order to verify the isolation performance of the vertical component isolation system, 1/8 series of shaking table tests using a scale model were conducted. The test model was composed of 4 vertical isolation devices, common deck and horizontal load suspension system. For the design earthquake, the system smoothly operated, and sufficient isolation characteristics were shown. The simulation analysis results matched well the test results, so the validity of the design technique was able to be verified. As the result, the prospect that the vertical isolation system applied to the FBR plant could technically realize was obtained.

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Full-Scale Dynamic Testing of a Sliding Seismically Isolated Unibody House

Earthquake Spectra ◽

10.1193/010616eqs003m ◽

2016 ◽

Vol 32 (4) ◽

pp. 2245-2270 ◽

Cited By ~ 15

Author(s):

Ezra Jampole ◽

Gregory Deierlein ◽

Eduardo Miranda ◽

Benjamin Fell ◽

Scott Swensen ◽

...

Keyword(s):

Seismic Isolation ◽

Computational Models ◽

Low Cost ◽

Ground Motions ◽

Design Guidelines ◽

Full Scale ◽

Shaking Table ◽

Galvanized Steel ◽

Isolation System ◽

Seismically Isolated

Shaking table tests were conducted on a new low cost sliding seismic isolation system aimed at significantly improving the seismic performance of low-rise lightweight residential construction. A two-story, full-scale seismically isolated wood frame house was tested dynamically under multiple ground motions on a shake table. Two different sliding isolation bearings were evaluated, one with flat and another with concave sliding surfaces, both with high-density polyethylene sliders on galvanized steel surfaces with a coefficient of friction of approximately 0.18. Each isolation system was subjected to seven severe recorded earthquake ground motions, which produced peak isolator displacements of up to 41 cm. The maximum induced inertial shear force on the superstructure was on the order of 0.4 g, yet the house remained practically damage-free with story drift ratios less than 0.1%. The study successfully (1) provides a proof-of-concept for design, construction, and behavior of a light-frame house with low-cost high friction sliding seismic isolation, (2) confirms several design assumptions regarding isolation behavior and maximum isolation displacement, and (3) provides data to validate computational models and develop design guidelines for the isolated superstructure.

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Research and Development of Three-Dimensional Isolation System for Sodium-Cooled Fast Reactor: Part 3 — Characteristics for Elements on Basis of Half-Scale Loading Tests

Volume 8: Seismic Engineering ◽

10.1115/pvp2019-93475 ◽

2019 ◽

Author(s):

Takahiro Somaki ◽

Tsuyoshi Fukasawa ◽

Shigeki Okamura ◽

Takayuki Miyagawa ◽

Masato Uchita ◽

...

Keyword(s):

Fast Reactor ◽

Seismic Isolation ◽

Design Method ◽

Three Dimensional ◽

Isolation System ◽

Rubber Bearing ◽

In Series ◽

Loading Tests ◽

Rubber Bearings ◽

Disc Spring

Abstract The authors have been developing the three-dimensional isolation system for a Sodium-cooled Fast Reactor, and reported the details of characteristics of disc springs and vertical oil dampers on the basis of full-scale loading tests [1]. To clarify the fundamental characteristics of the three-dimensional isolation system, the loading tests using a half-scale assembled specimen have been planned, which is composed of a rubber bearing, disc spring units, the horizontal supporting functions, the smoothly sliding elements, and the rotate restraint elements. This paper describes each characteristic of the rubber bearings, disc springs and sliding element before assembling a half-scale specimen of the three-dimensional seismic isolation system by the static or dynamic loading. The applicability of design method, the scaling effect in disc springs, and the dependence on the friction coefficient of the sliding elements were investigated and confirmed. Additionally, the method of minimizing the variation of force-displacement relationships between four disc spring units, each of which has the three disc springs stacked in parallel and six disc springs stacked in series, was studied. It should be noted that this paper is in series from Part 2 [1] held on 2018PVP.

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Isolation Performance of Intelligent Seismic Isolation System Using Air Bearing

Volume 8: Seismic Engineering ◽

10.1115/pvp2009-77600 ◽

2009 ◽

Cited By ~ 1

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.

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Shaking Table Test Study on Mid-Story Isolation Structures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.446-449.378 ◽

2012 ◽

Vol 446-449 ◽

pp. 378-381

Author(s):

Jian Min Jin ◽

Ping Tan ◽

Fu Lin Zhou ◽

Yu Hong Ma ◽

Chao Yong Shen

Keyword(s):

Seismic Response ◽

Seismic Isolation ◽

Shaking Table Test ◽

Base Isolation ◽

Shaking Table ◽

Natural Period ◽

Isolation System ◽

Isolation Layer ◽

Lead Rubber Bearing ◽

Complex Structural

Mid-story isolation structure is developing from base isolation structures. As a complex structural system, the work mechanism of base isolation structure is not entirely appropriate for mid-story isolation structure, and the prolonging of structural natural period may not be able to decrease the seismic response of substructure and superstructure simultaneously. In this paper, for a four-story steel frame model, whose prototype first natural period is about 1s without seismic isolation design, the seismic responses and isolation effectiveness of mid-story isolation system with lead rubber bearing are studied experimentally by changing the location of isolation layer. Respectively, the locations of isolation layer are set at bottom of the first story, top of the first story, top of the second story and top of the third story. The results show that mid-story isolation can reduce seismic response in general, and substructure acceleration may be amplified.

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Geotechnical Seismic Isolation System - Experimental Study

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.163-167.4449 ◽

2010 ◽

Vol 163-167 ◽

pp. 4449-4453

Author(s):

Wei Xiong ◽

Hing Ho Tsang ◽

S.H. Lo ◽

Shou Ping Shang ◽

Hai Dong Wang ◽

...

Keyword(s):

Seismic Isolation ◽

Dynamic Performance ◽

Testing Procedure ◽

Shaking Table ◽

Isolation System ◽

Isolation Technique ◽

Sand Mixture ◽

Seismic Hazard Mitigation ◽

Constituent Material ◽

Different Levels

In this study, an experimental investigation program on a newly proposed seismic isolation technique, namely “Geotechnical Seismic Isolation (GSI) system”, is conducted with an aim of simulating its dynamic performance during earthquakes. The testing procedure is three-fold: (1) A series of cyclic simple shear tests is conducted on the key constituent material of the proposed GSI system, i.e., rubber-sand mixture (RSM) in order to understand its behavior under cyclic loadings. (2) The GSI system is then subjected to a series of shaking table tests with different levels of input ground shakings. (3) By varying the controlling parameters such as percentage of rubber in RSM, thickness of RSM layer, coupled with the weight of superstructure, a comprehensive parametric study is performed. This experimental survey demonstrates the excellent performance of the GSI system for potential seismic hazard mitigation.

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Three Dimensional Seismic Isolation System Using Hydraulic Cylinder

Seismic Engineering, Volume 2 ◽

10.1115/pvp2002-1429 ◽

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.

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Comparative analysis of conventional and new seismically isolated structure

Gradjevinski materijali i konstrukcije ◽

10.5937/grmk2103185r ◽

2021 ◽

Vol 64 (3) ◽

pp. 185-193

Author(s):

Jelena Ristić ◽

Miloš Vučinić ◽

Danilo Ristić ◽

Milutin Vučinić

Keyword(s):

Seismic Isolation ◽

Low Cost ◽

Seismic Energy ◽

Seismic Excitation ◽

Isolation System ◽

Vibration Period ◽

International Projects ◽

Dominant Period ◽

Efficient Protection ◽

Seismically Isolated

Extensive analytical and experimental research has been done by the authors directed to mitigation of the effects of earthquakes on structures. The research results mainly represent parts of the realized several related international projects. A selected part of the analytical studies directed to comparison between conventional and seismically isolated frame structures is presented in this paper. The responses of the applied newely developed advanced seismic isolation system HC-RMS-GOSEB to the simulated input excitation of three representative earthquakes of intensity 0.50g, have shown that it is very effective for construction of vibro-isolated and seismically resistant buildings, providing activated multistage seismic response and globally optimized seismic energy balance. Its application achieves an increase in the vibration period of the structure, far enough from the dominant period of seismic excitation. The results of the research confirm that this system is a potential solution for achieving low-cost and highly efficient protection of buildings.

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