• Title, Summary, Keyword: isolation

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Shock absorption of concrete liquid storage tank with different kinds of isolation measures

  • Jing, Wei;Chen, Peng;Song, Yu
    • Earthquakes and Structures
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    • v.18 no.4
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    • pp.467-480
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    • 2020
  • Concrete rectangular liquid storage tanks are widely used, but there are many cases of damage in previous earthquakes. Nonlinear fluid-structure interaction (FSI) is considered, Mooney-Rivlin material is used for rubber bearing, nonlinear contact is used for sliding bearing, numerical calculation models of no-isolation, rubber isolation, sliding isolation and hybrid isolation concrete rectangular liquid storage tanks are established; dynamic responses of different structures are compared to verify the effectiveness of isolation methods; and influences of earthquake amplitude, bidirectional earthquake and far-field long-period earthquake on dynamic responses are investigated. Results show that for liquid sloshing wave height, rubber isolation cause amplification effect, while sliding isolation and hybrid isolation have reduction effect; displacement of rubber isolation structure is much larger than that of sliding isolation with limiting-devices and hybrid isolation structure; when PGA is larger, wall cracking probability of no-isolation structure becomes larger, and probability of liquid sloshing wave height and structure displacement of rubber isolation structure exceeds the limit is also larger; under bidirectional earthquake, occurrence probabilities that liquid sloshing wave height and structure displacement of rubber isolation structure exceed the limit will be increased; besides, far-field long-period earthquake mainly influences structure displacement and liquid sloshing wave height. On the whole, control effect of sliding isolation is the best, followed by hybrid isolation, and rubber isolation is the worst.

Experimental Study on Railway Vibration Isolation of a Large Structure using Isolation Materials (방진재를 이용한 대형구조물의 철도 진동에 관한 실험적 연구)

  • Ryu, Bong-Jo;Lee, Hong-Gi;Koo, Kyung-Wan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.6
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    • pp.1286-1292
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    • 2011
  • The paper deals with the vibration isolation of a large structure using an experimental technology. In the case of vibration isolation for the vicinity of a subway or a railroad station, most of vibration isolation techniques using isolation materials with high isolation efficiency only, have been applied. Therefore, the quantitative evaluation and design technologies are required for a vibration isolation of large structures. In this study, firstly, vibration characteristics due to train or subway are analyzed. Secondly, the performance of existing vibration isolation materials such as precision isolation material, elastomer is estimated through the experiments. Thirdly, the performance of a tire isolation material and its frame is tested and evaluated. Finally, it is shown that tire isolation materials can be applied to the vibration isolation or vibration reduction of large structures.

Semismic Analysis of Building Structures with Base Isolation System (Base Isolation System이 있는 건물의 지진하중에 대한 동적해석)

  • 이동근;이정석
    • Computational Structural Engineering
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    • v.3 no.1
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    • pp.71-81
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    • 1990
  • The isolation system is installed at the base of a structure for reduction of the earthquake damage to the structure. In the 1970', when the laminated rubber bearing(LR type) is developed, the isolation system is put in practice. And recently a new isolation system(SR type), including the laminated rubber bearing with the friction plate beneath, is developed. In this thesis, a study on the base isolation effect, for various of the isolation system and structure properties, is performed. The results of this parameter study show that the isolation system can reduce the earthquake damage of the building structures significantly. As the period of isolation system increases, the isolation effect increases and converges to zero damage. As the number of story increases, the isolation effect reduces. It is found that SR type isolation system is more effective than LR type because SR type base isolation system reduces acceleration, drift and total displacement.

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Conceptual Application Schemes of Seismic Isolation Techniques to Hanok (한옥의 면진기법 적용 방안에 대한 개념적 고찰)

  • Park, Bum-Soo;Kim, Yeong-Min;Hur, Moo-Won;Lee, Sang-Hyun
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.36 no.1
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    • pp.137-146
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    • 2020
  • In this study, various application schemes of seismic isolation system which can be applied to Hanok have been studied by analyzing its structural characteristics under seismic load. Structural stability of Hanok is more required against seismic load as Hanok becomes long-spanned and multi-storied. To meet this goal, it becomes necessary to study more advanced technology such as seismic isolation design as well as seismic control design and seismic resistant design suitable to Hanok. Seismic isolation systems have been successfully applied to RC and steel structures to improve structural performance during earthquakes. Based on these previous study, we proposed four application schemes of seismic isolation design suitable for Hanok and analyzed their structural characteristics and applicability to Hanok in conceptual level based on its structural characteristics. The proposed four schemes are base isolation method, ground isolation method, roof isolation method and intermediate-story isolation method. The applicability of the proposed method was evaluated by performing boundary nonlinear dynamic analysis to the typical Hanok for the two types of isolation method, that is, ground isolation method and roof isolation method, and the results showed that the proposed methods produced good performance enough to be applied to Hanok.

Application of Mid-story Isolation System for Seismic Response Reducing of Dome Structure (돔 구조물의 지진응답 저감을 위한 중간 면진장치의 적용)

  • Kim, Gee-Cheol;Kim, Su-Geun;Kang, Joo-Won
    • Journal of the Korean Association for Spatial Structures
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    • v.16 no.4
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    • pp.37-44
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    • 2016
  • The seismic isolation system reduces the seismic vibration that is transmitted from foundation to upper structure. This seismic isolation system can be classified into base isolation and mid-story isolation by the installation location. In this study, the seismic behavior of dome structure with mid-story isolation is analyzed to verify the effect of seismic isolation. Mid-story isolation is more effective than base isolation to reduce the seismic responses of roof structure. Also, this isolation would be excellent in structural characteristics and construction.

A Development of Vibration Isolation Technology for a Large Structure using Experimental Research (실험적 기법을 이용한 대형구조물 교통진동 차진기술 개발)

  • Ryu, B.J.;Lee, H.G.;Son, S.W.;Lee, G.S.;Han, H.H.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.537-542
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    • 2006
  • This paper deals with the vibration isolation techniques for a large structure using experimental research. In the case of vibration isolation for the vicinity of a subway or a railroad station, most of vibration isolation techniques using isolation materials with high isolation efficiency only, have been applied. Therefore, the quantitative evaluation and design technologies are required for a vibration isolation of large structures. In this study, firstly, vibration characteristics due to train or subway are analyzed. Secondly, the performance of existing vibration isolation materials such as precision isolation material, elastomer is estimated through the experiments. Thirdly the performance of tire isolation material and its frame is tested and evaluated.

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Vibration Control Performance Evaluation of Hybrid Mid-Story Isolation System for a Tall Building (하이브리드 중간층 지진격리시스템의 고층 건물 진동 제어 성능 평가)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of the Korean Association for Spatial Structures
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    • v.18 no.3
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    • pp.37-44
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    • 2018
  • A base isolation system is widely used to reduce seismic responses of low-rise buildings. This system cannot be effectively applied to high-rise buildings because the initial stiffness of the high-rise building with the base isolation system maintains almost the same as the building without the base isolation system to set the yield shear force of the base isolation system larger than the design wind load. To solve this problem, the mid-story isolation system was proposed and applied to many buildings. The mid-story isolation system has two major objectives; first to reduce peak story drift and second to reduce peak drift of the isolation story. Usually, these two objectives are in conflict. In this study, a hybrid mid-story isolation system for a tall building is proposed. A MR (magnetorheological) damper was used to develop the hybrid mid-story isolation system. An existing building with mid-story isolation system, that is "Shiodome Sumitomo Building" a high rise building having a large atrium in the lower levels, was used for control performance evaluation of the hybrid mid-story isolation system. Fuzzy logic controller and genetic algorithm were used to develop the control algorithm for the hybrid mid-story isolation system. It can be seen from analytical results that the hybrid mid-story isolation system can provide better control performance than the ordinary mid-story isolation system and the design process developed in this study is useful for preliminary design of the hybrid mid-story isolation system for a tall building.

Seismic Isolation Effects Due to the Difference Between the Center of Mass of the Building and the Center of Stiffness of Isolation Layer (건물의 질량중심과 면진층의 강성중심 차이에 따른 면진효과)

  • Hur, Moo-Won;Chun, Young-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.5
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    • pp.107-115
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    • 2014
  • In this study, we examined the seismic isolation effects due to the difference between the center of mass of the building and the center of stiffness of isolation layer. Because the base isolation technique is a technique that is highly dependent on the performance of seismic isolation devices installed on the seismic isolation layer, we have to examine the horizontal stiffness of seismic isolation devices after making them. If difference between the design stiffness and the actual stiffness of the seismic isolation device occurred, a big problem may be generated in the upper members on the seismic isolation layer. The analytical results show that the more eccentricity increases, the more maximum response acceleration, story shear and the member forces of the upper part of the structure increases, and the damage is expected to be in excess. Therefore, it is recommended that if possible, isolation devices have to be designed to coincide the center of mass of the building with the center of stiffness of isolation layer. If not after making isolation devices, they need to be relocated to prevent the eccentricity.

A Method to Improve Isolation for Passive RFID Applications (수동형 RFID 시스템 적용을 위한 Isolation 개선 방법)

  • Kim, Jae-Kwon;Burm, Jin-Wook
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.44 no.4
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    • pp.45-49
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    • 2007
  • The isolation between transmitter and receiver has been a critical problem in a pulse-modulated RFID (Radio Frequency Identification) system where transmitter and receiver use the identical frequency. A method using a switch, a mixer, a BPF (band-pass filter), and an additional oscillator in the transmitter is proposed to improve the isolation between transmitter and receiver in an RFID system. The Proposed system up-converts the outgoing wave from a frequency different from the received signal and improves the isolation. The proposed method provided additional 20 dB improvement on the isolation.

Investigation of Adaptability of Smart Top-Story Isolation System to Structures in Regions of Low-to-Moderate Seismicity (스마트 최상층 면진시스템의 중약진지역 적용성 평가)

  • Kim, Hyun-Su;Kang, Joo-Won
    • Journal of the Korean Association for Spatial Structures
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    • v.12 no.4
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    • pp.71-80
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    • 2012
  • Because a smart isolation system cannot be used as a base isolation system for tall buildings, top-story or mid-story isolation systems are required. In this study, adaptability of a smart top-story isolation system for reduction of seismic responses of tall buildings in regions of low-to-moderate seismicity has been investigated. To this end, 20-story example building structure was selected and an MR damper and low damping elastomeric bearings were used to compose a smart base isolation system. Artificial earthquakes generated based on design spectrum of low-to-moderate seismicity regions are used for structural analyses. Based on numerical simulation results, it has been shown that a smart top-story isolation system can effectively reduce both structural responses and isolation story drifts of the building structure in low-to-moderate seismicity regions in comparison with a passive top-story isolation system.