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 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.

scholarly journals Comparative analysis of conventional and new seismically isolated structure

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.

scholarly journals Large-scale experimental investigation of a low-cost PVC ‘sand-wich’ (PVC-s) seismic isolation for developing countries

2020 ◽  
Vol 36 (4) ◽  
pp. 1886-1911 ◽  
Author(s):  
Anastasios Tsiavos ◽  
Anastasios Sextos ◽  
Andreas Stavridis ◽  
Matt Dietz ◽  
Luiza Dihoru ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Developing Countries ◽  
Ground Motion ◽  
Seismic Isolation ◽  
Large Scale ◽  
Low Cost ◽  
Seismic Energy ◽  
Earthquake Ground Motion ◽  
Isolation System ◽  
Seismically Isolated

This study presents a large-scale experimental investigation on the seismic performance of an innovative, low-cost seismic isolation system for developing countries. It is based on the beneficial effect of the encapsulation of sand grains between two PVC surfaces on the initiation of sliding and the dissipation of seismic energy between the surfaces. A three-times scaled-down, idealized, seismically isolated model of a prototype single-story structure located in Nepal is subjected to an ensemble of recorded earthquake ground motion excitations. The experimentally derived response of the seismically isolated structure is compared with the response of the corresponding fixed-base structure. This system is part of a wider hybrid design approach where the structure is designed to resist the seismic forces at the design acceleration level. The seismic isolation system sets an upper bound to the response of the structure for ground motion excitations exceeding the design level.

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.

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.

scholarly journals Low Cost Frictional Seismic Base-Isolation of Residential New Masonry Buildings in Developing Countries: A Small Masonry House Case Study

2017 ◽  
Vol 11 (1) ◽  
pp. 1026-1035 ◽  
Author(s):  
Ahmad Basshofi Habieb ◽  
Gabriele Milani ◽  
Tavio Tavio ◽  
Federico Milani
Keyword(s):  
Finite Element ◽  
Seismic Vulnerability ◽  
Base Isolation ◽  
Low Cost ◽  
Element Model ◽  
Shaking Table ◽  
Fe Model ◽  
Isolation System ◽  
Finite Element Software ◽  
Non Linear

Introduction:An advanced Finite Element model is presented to examine the performance of a low-cost friction based-isolation system in reducing the seismic vulnerability of low-class rural housings. This study, which is mainly numerical, adopts as benchmark an experimental investigation on a single story masonry system eventually isolated at the base and tested on a shaking table in India.Methods:Four friction isolation interfaces, namely, marble-marble, marble-high-density polyethylene, marble-rubber sheet, and marble-geosynthetic were involved. Those interfaces differ for the friction coefficient, which was experimentally obtained through the aforementioned research. The FE model adopted here is based on a macroscopic approach for masonry, which is assumed as an isotropic material exhibiting damage and softening. The Concrete damage plasticity (CDP) model, that is available in standard package of ABAQUS finite element software, is used to determine the non-linear behavior of the house under non-linear dynamic excitation.Results and Conclusion:The results of FE analyses show that the utilization of friction isolation systems could much decrease the acceleration response at roof level, with a very good agreement with the experimental data. It is also found that systems with marble-marble and marble-geosynthetic interfaces reduce the roof acceleration up to 50% comparing to the system without isolation. Another interesting result is that there was little damage appearing in systems with frictional isolation during numerical simulations. Meanwhile, a severe state of damage was clearly visible for the system without isolation.

Friction-Type Seismic Isolation Device of Steel Pile Foundation in Shaking Table Tests and its Numerical Simulations

2016 ◽  
Vol 845 ◽  
pp. 233-239
Author(s):  
Buntara Sthenly Gan ◽  
Susumu Nakamura ◽  
Noriaki Sento ◽  
Kosuke Ito
Keyword(s):  
Numerical Simulations ◽  
Pile Foundation ◽  
Seismic Isolation ◽  
Low Cost ◽  
Time History ◽  
Shaking Table ◽  
Steel Sphere ◽  
Pile Cap ◽  
Isolation Device ◽  
Nonlinear Time History

Pile foundation equipped with a low-cost frictional type seismic isolation device is investigated. The frictional mechanism results from a contact between two surfaces of a half steel sphere mounted on the pile cap and the corresponding inner steel sphere embedded in the footing of upper structure. To verify the mechanical behaviors of the pile with frictional type seismic isolation device, tests, and its numerical simulations have been performed. The rotational friction device is found to be very effective in releasing the internal energy transferred from the pile foundation to the upper structure. The behavior of the friction-type device was studied by modeling using the nonlinear time history dynamic analysis. It was observed that the responses of the structures with devices can be approximated by using springs and dampers model.

Current State of Seismic-Isolation Design

2009 ◽  
Vol 4 (3) ◽  
pp. 175-181 ◽  
Author(s):  
Nagahide Kani ◽  
Keyword(s):  
Seismic Isolation ◽  
Structural Safety ◽  
Current Status ◽  
Property Value ◽  
Isolation System ◽  
High Rise ◽  
Current State ◽  
Safety Property ◽  
Seismically Isolated ◽  
Resistance Performance

Japan has the world’s highest number of seismic-isolation structures - a figure that has been gradually increasing since the 1995 South Hyogo earthquake that devastated Kobe and its environs. It is the main reason that two seismically isolated buildings in Kobe have shown good performance during and after earthquakes. As the awareness of the benefits of seismic isolation has grown, it is being accepted more among people, to maintain structural safety and functionality during and after earthquakes. Safety, property value, and functionality must be maintained by the earthquake-resistance performance of buildings. This seismic isolation system is the appropriate earthquake-resistant method in consideration of satisfying these three items, and positive in the design of structures, such as residences, hospitals, and high-rise buildings, then in retrofitting. This paper focuses on the current status of seismically isolated structures and problems in seismic isolation design.

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