A hybrid seismic isolation system toward more resilient structures: Shaking table experiment and fragility analysis

2021 ◽  
Vol 38 ◽  
pp. 102194
Author(s):  
Zoran Rakicevic ◽  
Aleksandra Bogdanovic ◽  
Ehsan Noroozinejad Farsangi ◽  
Abbas Sivandi-Pour
Keyword(s):  
Seismic Isolation ◽  
Shaking Table ◽  
Fragility Analysis ◽  
Isolation System

Shaking Table Test Study on Mid-Story Isolation Structures

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.

Geotechnical Seismic Isolation System - Experimental Study

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.

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.

Experimental Study on Vertical Component Seismic Isolation System With Coned Disk Spring

2005 ◽  
Author(s):  
S. Kitamura ◽  
S. Okamura ◽  
K. Takahashi
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Vertical Component ◽  
Shaking Table ◽  
Scale Model ◽  
Test Model ◽  
Isolation System

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.

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

2016 ◽  
Vol 32 (4) ◽  
pp. 2245-2270 ◽  
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.

Shaking Table Test Study on Mid-Story Isolation Structures with Viscous Damper

2012 ◽  
Vol 226-228 ◽  
pp. 1149-1152
Author(s):  
Jian Min Jin ◽  
Ping Tan ◽  
Fu Lin Zhou ◽  
Xiang Yun Huang
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Shaking Table Test ◽  
Base Isolation ◽  
Shaking Table ◽  
Viscous Damper ◽  
Natural Period ◽  
Isolation System ◽  
Isolation Layer ◽  
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 linear natural rubber bearing and viscous damper 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.

Parameter Analysis and Shaking Table Test Based on Mechanics Analysis in Seismic Isolation System of Transformer with Bushings

2013 ◽  
Vol 859 ◽  
pp. 33-42
Author(s):  
Mei Gen Cao ◽  
Juan Mo
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Shaking Table Test ◽  
Power Transformer ◽  
Shaking Table ◽  
Parameter Analysis ◽  
Particle Analysis ◽  
Isolation System ◽  
Large Power ◽  
Isolation Layer

Earthquake damage many times in history indicate thatthe destroy type of large power transformer is diverse in earthquake andvulnerability is very high. Isolationtechnology can effectively reduce seismic response of the transformer and bushings,but transformer isolation layer design and parameter selection have a largerimpact on the isolation effect. Firstly, one transformer model installing 220,500kV real bushings for testing and analysis is designed which its structural dimension is closer totrue transformer. Multi-particle analysis model of the transformer withbushings isolation system (TBIS)and the equations of motion are established, and calculationprocedures are compiled using MATLABprogram. Secondly, impacts analysis on equivalent horizontal stiffness and dampingratio of the isolation layer are carried out subjectedto earthquake. Reasonable ranges ofstiffness and damping parameters have been determined. Earthquake simulatortesting of the transformer with real bushings is implement which transformertank filled with water in the test. Acceleration, displacement and stressresponse of transformer and bushings with or without isolation bearings wereobtained. Analysis and experiments show that the rational designing isolationlayer parameters can effectively reduce the seismic response of transformers andbushings. In conclusion, mentioned above research have reference role toseismic isolation design and application for power transformer and bushings forthe future.

Shaking Table Tests With Large Test Specimens of Seismically Isolated FBR Plants: Part 3—Ultimate Behavior of Upper Structure and Rubber Bearings

2009 ◽  
Author(s):  
Shuichi Yabana ◽  
Kenji Kanazawa ◽  
Seiji Nagata ◽  
Seiji Kitamura ◽  
Takeshi Sano
Keyword(s):  
Seismic Isolation ◽  
Response Spectra ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Nuclear Facilities ◽  
Restoring Force ◽  
Isolation System ◽  
Seismically Isolated ◽  
Design Earthquake ◽  
Rubber Bearings

This paper describes results of shaking table tests to grasp ultimate behavior of seismic isolation system under extremely strong earthquake motions, including failure of rubber bearings. The results of the shaking table tests are expected to be useful for the design of seismically isolated nuclear facilities, especially fast breeder reactor (FBR) plants. In the test, lead rubber bearings, of which the diameter is 505 mm and about 1/3 scale of a prototype in planning FBR plants, are used; the test specimens are loaded by the largest three-dimensional shaking table in E-defense of National Research Institute for Earth Science and Disaster Prevention (NIED) of Japan. Failure of rubber bearings occurs with amplified tentative design earthquake motions. From the tests, the ultimate responses of the upper structure and rubber bearings are presented. In particular, the change of floor response spectra and restoring force characteristics of rubber bearings according to increase of input motions is discussed. Furthermore, mechanism of the failure of rubber bearings is investigated from the observation of failure surfaces and cut sections, static loading tests, and material tests of rubber bearings. Finally, the function of seismic isolation system after the failure of a part of rubber bearings is confirmed under the tentative design earthquake.

Geotechnical Seismic Isolation System - Further Experimental Study

2014 ◽  
Vol 580-583 ◽  
pp. 1490-1493 ◽  
Author(s):  
Wei Xiong ◽  
Ming Ren Yan ◽  
Yao Zhuang Li
Keyword(s):  
Experimental Study ◽  
Dynamic Response ◽  
Parametric Study ◽  
Seismic Isolation ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Seismic Acceleration ◽  
Isolation System ◽  
Isolation Performance

The isolation effectiveness of the Geotechnical Seismic Isolation (GSI) system was further investigated via a series of prescribed shaking-table tests. The dynamic response of GSI system was also evaluated in detail of this work. A parametric study for assessment of the isolation performance of GSI was conducted by varying experimental key parameters, such as rubber percentage of rubber-sand mixtures (RSM), configuration of the foundation, storey number of the superstructure, and different kinds of seismic acceleration inputs. From the parametric survey, it can be concluded that the GSI system can to some extent attenuate the dynamic response of the superstructure under big earthquake shakings.

Seismic Isolation of the IRIS Nuclear Plant

2009 ◽  
Author(s):  
Massimo Forni ◽  
Alessandro Poggianti ◽  
Fosco Bianchi ◽  
Giuseppe Forasassi ◽  
Rosa Lo Frano ◽  
...  
Keyword(s):  
Seismic Isolation ◽  
Seismic Analysis ◽  
Wide Spectrum ◽  
Seismic Excitation ◽  
Fragility Analysis ◽  
Pressurized Water ◽  
Isolation System ◽  
Order Of Magnitude ◽  
Safety Features ◽  
The Impact

The safety-by-design™ approach adopted for the design of the International Reactor Innovative and Secure (IRIS) resulted in the elimination by design of some of the main accident scenarios classically applicable to Pressurized Water Reactors (PWR) and to the reduction of either consequences or frequency of the remaining classical at-power accident initiators. As a result of such strategy the Core Damage Frequency (CDF) from at-power internal initiating events was reduced to the 10−8/ry order of magnitude, thus elevating CDF from external events (seismic above all) to an even more significant contributor than what currently experienced in the existing PWR fleet. The same safety-by-design™ approach was then exported from the design of the IRIS reactor and of its safety systems to the design of the IRIS Nuclear Steam Supply System (NSSS) building, with the goal of reducing the impact of seismically induced scenarios. The small footprint of the IRIS NSSS building, which includes all Engineered Safety Features (ESF), all the emergency heat sink and all the required support systems makes the idea of seismic isolation of the entire nuclear island a relatively easy and economically competitive solution. The seismically isolated IRIS NSSS building dramatically reduces the seismic excitation perceived by the reactor vessel, the containment structure and all the main IRIS ESF components, thus virtually eliminating the seismic-induced CDF. This solution is also contributing to the standardization of the IRIS plant, with a single design compatible with a variety of sites covering a wide spectrum of seismic conditions. The conceptual IRIS seismic isolation system is herein presented, along with a selection of the preliminary seismic analyses confirming the drastic reduction of the seismic excitation to the IRIS NSSS building. Along with the adoption of the seismic isolation system, a more refined approach to the computation of the fragility analysis of the components is also being developed, in order to reduce the undue conservatism historically affecting seismic analysis. The new fragility analysis methodology will be particularly focused on the analysis of the isolators themselves, which will now be the limiting components in the evaluation of the overall seismic induced CDF.

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