• Title/Summary/Keyword: 적층고무받침

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Estimation of Aseismatic Performance of Laminated Rubber Bearing Through Shaking Table Tests (진동대 실험을 통한 적층고무받침의 내진성능 평가)

  • Park, Seong-Kyu
    • Journal of the Korean Society for Railway
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    • v.13 no.4
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    • pp.440-446
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    • 2010
  • This paper was investigated on the laminated rubber bearing, which mitigates damages of bridges from threat of earthquakes. Laminated rubber bearing can bear large loads for long periods of time and be capable of large deformations during an earthquake. To evaluate seismic isolation with laminated rubber bearing on several earthquake waves, we performed a shaking table test. In this test, deck acceleration was measured by accelerometers and shear force on piers was surveyed by load cells. Furthermore, seismic capacity of isolated systems with laminated rubber bearing was compared with non-isolated systems through shaking table test. The results show that deck acceleration and shear force were relatively reduced by laminated rubber bearing.

Effects of Accelerated Thermal Aging on Dynamic Properties of Laminated Rubber Bearings (적층고무받침의 가속 열 노화 동적특성 영향)

  • Oh, Ju;Jung, Hie-Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.5A
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    • pp.417-424
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    • 2010
  • The dynamic properties of laminated rubber bearings used as isolators in structures could be significantly deteriorated because of the change of microstructure in rubber caused by thermal aging. As a result, a catastrophic failure of bridges and buildings unexpectedly occurs when they are subjected to earthquake attack. Here, the dynamic properties of laminated rubber bearings before and after different of compression-shear loading and repeated cycles loadings, ultimated failure test with thermal aging were first measured and compared to each other. The experimental results, the effects of thermal aging on the shear stiffness, energy absorption, and equivalent damping coefficient of laminated rubber bearings are investigated. It is found that the deterioration of dynamic properties of laminated rubber bearings caused by thermal aging is significant and should be taken into account in designing rubber bearings.

Pseudo-Dynamic Test for the Bridges Retrofitted with Laminated Rubber Bearings (적층고무받침으로 내진보강된 교량의 유사동적실험)

  • Kwak, Im-Jong;Cho, Chang-Beck;Han, Kyoung-Bong;Kim, Young-Jin;Kwak, Jong-Won
    • Journal of the Earthquake Engineering Society of Korea
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    • v.9 no.1 s.41
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    • pp.43-50
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    • 2005
  • Many highway bridges in Korea need seismic retrofit because only one decade has passed since the seismic design criteria was introduced. For the highway bridges of which bearings are worn and dysfunctional, the validity of seismic retrofit method using laminated rubber bearings was discussed in this study. Real scale RC pier specimens without seismic details were constructed. And then, Pot bearing, Rubber bearing (RB), Lead-rubber bearing (LRB) were applied to these specimens. Through pseudo dynamic test method, dynamic behavior of these RC piers under earthquake was simulated and compared. From the test results, proposed seismic retrofit method was found to be valid.

Seismie Performance Evaluation of Reinforced Concrete Bridge Piers Supported by Laminated Rubber Bearings (적층고무받침을 사용한 철근콘크리트 교각의 내진성능평가)

  • 김태훈;최정호;신현목
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.2
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    • pp.63-72
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    • 2004
  • The purpose of this study is to evaluate seismic performance of reinforced concrete bridge piers supported by laminated rubber bearings. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. Seismic isolator element is developed to predict behaviors of laminated rubber bearings. The proposed numerical method for seismic performance evaluation of reinforced concrete bridge piers supported by laminated rubber bearings is verified by comparison with reliable experimental results.

Experimental Study on Ultimate Tensile Failure Properties of Laminated Rubber Bearings (적층고무받침의 극한인장파괴 특성에 관한 실험적 연구)

  • Oh, Ju;Jung, Hie-Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.4A
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    • pp.303-309
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    • 2011
  • Laminated rubber bearing is the most commonly used device for seismic base isolation of bridge structures. It is important to know performance and behavior characteristics of the laminated rubber bearings. The main evaluation factors of the rubber bearing are classified as compressive, shear and tensile behavior characteristics. The reference data of compressive and shear characteristics are rich, but the reference data of tensile characteristics is scarce. In this study, tensile test results of the rubber bearing with variation of shape factor and shear deformation are investigated for mechanical property. When tensile deformation in normal condition is increasing, tensile cycle behavior curve becomes non-linear and tensile breaking point is 300%. On the other hand, tensile breaking point is shear deformation condition is about 40%. Furthermore, when shape factor is lower, tensile breaking point is decrease. This results mean that tensile breaking point is decreased in triaxial tensile deformation because of cracks caused by internal void of the rubber bearings. This experimental data can be used as the reference data of tensile characteristics for designing seismic isolation of structures.

Compression and Shear Capacity of Rubber Bearings with Various Geometric Parameters (다양한 기하학적 인자를 고려한 고무받침의 압축 및 전단 내력)

  • Park, Ji Yong;Kim, Joo Woo;Jung, Hie Young
    • Journal of Korean Society of Steel Construction
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    • v.26 no.6
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    • pp.559-570
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    • 2014
  • In this study, compression and shear characteristics of laminated rubber bearings and lead rubber bearings with various parameters are investigated by using material and geometric nonlinear three-dimensional finite element analysis. Rubber coupon tests are performed to make a model of the laminated rubber bearings. In addition, the material constants of the rubber are calculated by the curve fitting process of stress-strain relationship. The finite element analysis and experimental tests of the laminate rubber bearings are used to verify the validity of the rubber material constants. It is seen that the compression behavior of the laminated rubber bearings and lead rubber bearings mainly varies depending on the first shape factors and their shear behavior significantly varies depending on the second shape factors. In addition, the horizontal stiffness and energy dissipation capacity of lead rubber bearing are increased when the diameter of a lead bar is increased.

활동형 지진격리 시스템을 적용한 지진격리 교량의 비선형 유한요소해석(S/W:ABAQUS, H/W:CrayC94)

  • 음성우
    • Computational Structural Engineering
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    • v.11 no.1
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    • pp.38-45
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    • 1998
  • 최근 국내외에서 활발히 개발되고 있는 지진격리 시스템은 원자력 발전소, 교량, 중요한 공공건물 등의 지진피해를 최소화하기 이하여 널리 적용되고 있다. 그리고 다른 방법에 비하여 경제성 및 효율성이 우수하기 때문에 관련 연구 및 응용이 활발히 진행되고 있다. 이에 따라 국내외에서 격리시스템의 비선형성과 구조물의 불연속성을 고려한 지진격리 구조물의 해석을 통한 거동을 규명하는 연구가 과거 수년간 활발히 진행되어 왔다. 당사(금호건설)는 상부하중 지지능력과 감쇠능력이 우수한 지진격리장치를 개발하였으며 지진격리장치를 설치한 교량의 지진해석을 수행하여 본 지진격리 시스템의 이론적 성능을 파악하였다. 본 수치해석은 CrayC94에 탑재된 비선형 해석에 뛰어난 것으로 알려진 ABAQU를 이용하였다. 본 지진격리 시스템은 적층고무받침(Laminated Rubber Bearing)과 PTFE 미끄럼받침으로 구성되어 있으며, 적층고무받침은 주로 복원력을 제공하며 PTFE 미끄럼받침은 상부하중을 지지하며 마찰감쇠를 제공하여 에너지를 소산하는 역할을 한다. 본 수치해석에서는 선형스프링과 마찰요소를 이용하여 각각을 모형화하였다. 개발된 지진격리 시스템이 주로 사용될 상판자중이 무거운 다경간 연속 PC Box Girder교를 모델교량으로 선택하여 해석을 수행하였으며 수치해석에 사용된 격리시스템의 사전에 수행된 동특성 실험결과를 활용하였다. 이러한 해석을 통하여 이론적 효율성을 파악할 수 있었다.

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An Experimental Study for the Shear Property and the Temperature Dependency of Seismic Isolation Bearings (지진격리받침의 전단특성 및 온도의존성에 대한 실험적 연구)

  • Cho, Chang-Beck;Kwahk, Im-Jong;Kim, Young-Jin
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.1
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    • pp.67-77
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    • 2008
  • Seismic isolation has been studied continuously as a solution of the seismic engineering to reduce the sectional forces and the damages of structures caused by earthquakes. To certify reliable design and installation of the seismic isolation systems, seismic isolation bearings should be fabricated under well planned quality control process, and proper evaluation tests for their seismic performance should be followed. In this study, shear property evaluation tests for the lead rubber bearings(LRB) and the rubber bearings(RB) were implemented and the temperature dependency tests were also implemented to evaluate the changes of shear properties according to the changes of temperature. After evaluation tests, the measured shear properties were compared to their design values and their deviation was analyzed comparing with the allowable error ranges specified in Highway Bridge Design Specifications. These results showed that a considerable number of isolation bearings have so large deviations from their design values that their error ranges were over or very close to the allowable ranges. And the test results for temperature dependency showed that the shear properties of isolation bearings would be changed in great degree by the change of temperature during their service period. If these two types of changes in their shear properties are superposed, it would possible that the changes of shear properties from their original design values are over than 50%.

The Pseudo-Dynamic Test for the Seismic Retrofit System Utilizing Existing Bridge Bearings (교량의 기존 받침을 활용하는 내진보강시스템의 유사동적 실험)

  • Kwahk, Im-Jong;Cho, Chang-Beck;Kim, Young-Jin;Kwark, Jong-Won
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.1 s.53
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    • pp.21-27
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    • 2007
  • In this study, an approach that installs seismic isolation bearings was proposed for the seismic retrofit of the existing bridges. The method that replaces all existing bearings with seismic isolators was proposed already. However, in this study, we recommend to utilize the existing bearings for the benefit of safety and cost. According to our proposal, the seismic isolators do not support vertical loads but they Just function as the period shifter and the horizontal damper. To verify this approach experimentally, the real scale bearings and lead rubber bearings far the real highway bridges were designed and fabricated. And the responses of this isolated bridges to the assumed earthquakes were determined by the pseudo dynamic test scheme. The test results were also compared to the responses computed by the well known structural analysis software to check the reliability of the test. From the test results, we found that the retrofitted bridges using the proposed method showed stable performances under earthquakes.

Shaking Table Tests of Base-Isolated Steel Frame (지진격리된 철골구조물의 진동대 실험)

  • 윤정방
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1997.04a
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    • pp.136-143
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    • 1997
  • 본 연구에서는 철골구조물을 대상으로 지진격리(Base-Isolation)를 사용하였을 때의 진동감소 효과를 분석하기 위하여 지진하중에 대한 진동대 실험을 수행하였다. 실험 대상구조물은 $\frac{1}{4}$축소모형의 3층 철골구조물이며, 입력지진은 여러 계측기록과 UBC 설계스펙트럼으로부터 3가지 지반조건에 대하여 작성한 인공지진기록을 사용하였다. 축소 실험모형은 기초가 고정된 일반적인 철골구조물과 적층고무받침(Laminated Rubber Bearing) 형식의 지진격리장치(Base Isolator)를 사용한 구조물을 동시에 설치하여 그 지진응답을 비교 관찰하였다. 대부분의 하중하에서 지진격리장치가 사용된 철골구조물의 경우에 지진응답이 현저히 감소하는 것을 알 수 있으나, 장주기파의 성분이 강한 지반운동에 대해서는 오히려 지진응답이 증가하였다. 그러나 여러 지반조건에 대하여 UBC 시방서에서 규정한 설계하중에 대하여는 진동감소효과가 우수함을 보인다.

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