• 한국지진공학회논문집
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• 제1권4호
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• pp.45-58
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• 1997

본 연구에서는 다양한 입력지진에 대해서 기초격리된 구조물의 내진성능 평가를 위해서 진동대실험과 유사동적실험을 수행하였다. 본 논문의 목적은 다음과 같다. 하나는 진동대실험을 통하여 강한 지진의 발생시 저층의 구조물에 대한 기초격리시스템의 내진성능을 평가하는 것이고 다음으로는 진동대실험결과와 비교하여 기초격리시스템에 대한 유사동적실험기법의 적용성 및 신뢰성을 증명하는 것이다. 진동대실험은 적층고무받침을 이용하여 기초격리된 1/4 축소모형의 3층 철골구조물의 대상으로 하였다. 유사동적실험에서는 부분구조기법을 사용하여 단지 기초격리시스템만을 대상으로 실험되며 전체구조물의 지진응답은 컴퓨터 내에서 직접적분을 이용하여 계산된다. 진동대실험결과와 비교할 때 부분구조기법을 사용한 유사동적실험은 기초격리된 구조물의 동적응답 평가에 매우 효과적임을 알 수 있었다. 또한 대부분의 하중하에서 기초격리장치가 사용된 구조물의 경우에는 지진응답이 현저히 감소하는 것을 알 수 있었으나, 장주기파의 성분이 강한 지반운동에 대해서는 감소의 폭이 크지 않았다. 그러나 여러 지반조건에 대하여 UBC 시방서에서 규정한 설계하중에 대하여는 진동감소효과가 우수함을 보인다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.465-474
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• 2001

Base Isolation system is an effective design strategy that provides a practical substitute for the seismic design of bridge. In this study, the dynamic tests was performed on HDB (Hysteretic Damping Bearing) and Dynapot. Then, the dynamic analysis was carried out for a bridge using the experimental results to estimate the seismic performance of bearings. Analysis for bridge was performed for four types of earthquake loadings. The result of dynamic test and theoretical analysis indicate that the performance of HDB and Dynapot is appropriate for the earthquake loading.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.662-665
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• 2004

In this paper, based on shaking table test results on a seismically isolated bridge model, an inelastic numerical model is refined by using Bouc-Wen model representing the hysteretic behavior of isolators. Seismic responses of isolated bridges are numerically investigated varying with relative stiffness ratios, which is a ratio of the effective stiffness of isolator to the lateral stiffness of bridge pier. From the results, it is found that an adequate range of relative stiffness ratio could be defined for seismic design of isolated bridges without considering the flexibility of piers.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1995년도 봄 학술발표회 논문집
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• pp.122-129
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• 1995

The seismic behavior of a rectangular liquid container with high damping laminated rubber bearing is investigated through the scaled model tests. The results are compared with those for non-isolated model, and those by analytical methods. It is shown that the optimum dynamic properties of isolation system can reduce the acceleration response in the superstructure significantly and prevent the amplification of sloshing height.

• Smart Structures and Systems
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• 제25권2호
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• pp.155-167
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• 2020

This paper demonstrates a real-time hybrid substructuring (RTHS) shake table test to evaluate the seismic performance of a base isolated building. Since RTHS involves a feedback loop in the test implementation, the frequency dependent magnitude and inherent time delay of the actuator dynamics can introduce inaccuracy and instability. The paper presents a robust stability and performance analysis method for the RTHS test. The robust stability method involves casting the actuator dynamics as a multiplicative uncertainty and applying the small gain theorem to derive the sufficient conditions for robust stability and performance. The attractive feature of this robust stability and performance analysis method is that it accommodates linearized modeled or measured frequency response functions for both the physical substructure and actuator dynamics. Significant experimental research has been conducted on base isolators and dampers toward developing high fidelity numerical models. Shake table testing, where the building superstructure is tested while the isolation layer is numerically modeled, can allow for a range of isolation strategies to be examined for a single shake table experiment. Further, recent concerns in base isolation for long period, long duration earthquakes necessitate adding damping at the isolation layer, which can allow higher frequency energy to be transmitted into the superstructure and can result in damage to structural and nonstructural components that can be difficult to numerically model and accurately predict. As such, physical testing of the superstructure while numerically modeling the isolation layer may be desired. The RTHS approach has been previously proposed for base isolated buildings, however, to date it has not been conducted on a base isolated structure isolated at the ground level and where the isolation layer itself is numerically simulated. This configuration provides multiple challenges in the RTHS stability associated with higher physical substructure frequencies and a low numerical to physical mass ratio. This paper demonstrates a base isolated RTHS test and the robust stability and performance analysis necessary to ensure the stability and accuracy. The tests consist of a scaled idealized 4-story superstructure building model placed directly onto a shake table and the isolation layer simulated in MATLAB/Simulink using a dSpace real-time controller.

• 한국구조물진단유지관리공학회 논문집
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• 제27권6호
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• pp.22-29
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• 2023

재료 및 부재의 내진성능평가 실험 시 재하속도와 수직하중은 성능에 중대한 영향을 미칠 수 있다. 반복 가력 및 하이브리드 실험 시 재하속도는 입력 변위와 출력 변위 사이의 시간 지연현상으로 인해 고속으로 제어하기 어려우며 횡방향 변위에 의해 수직하중을 일정하게 유지하는 것이 어려워 일정한 수직하중이 유지되는 고속 및 실시간 실험은 거의 이루어지지 않았다. 본 연구에서는 면진받침의 속도 의존성과 수직하중의 영향을 조사하기 위해 저속 및 고속 반복 가력 실험과 실시간 하이브리드 실험을 수행하였다. 실험에서 수평 변위와 수직 하중의 실시간 제어를 위해 Adaptive Time Series(ATS) 보정 방법과 State estimator가 포함된 FLB System을 구축하였다. 고속 또는 실시간으로 재하되는 수평 변위 제어 속도와 상부구조물에 의한 수직하중은 면진받침의 강도 및 지진 시 거동에 상당한 영향을 미칠 수 있음을 확인하였으며 내진성능평가를 위한 실험 시 실제와 유사하도록 구현되어야함을 알 수 있었다. 본 연구는 내진성능평가를 위해 구축하고 사용된 시스템의 우수한 성능을 보여주며 정확하고 효율적인 내진성능평가가 가능하도록 하였다.

• Earthquakes and Structures
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• 제26권1호
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• pp.1-15
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• 2024

Isolation technology has been proven effective in reducing the seismic response of superstructures, where most of the deformation is concentrated in the isolation layer. However, in cases of earthquakes with intensities surpassing the fortification level of the area, or severe near-fault earthquakes, the isolation layer may experience excessive deformation, resulting in damage to the isolation bearings or collisions with the retaining wall or surrounding buildings. In this study, a finite element model using ABAQUS is established and compared with experimental test results to deeply investigate the influence of limit devices on the isolation layer and its response to the superstructure. The findings reveal that a larger limiter stiffness and a smaller reserved gap can achieve a more effective limiting effect. Nevertheless, a smaller reserved gap and a larger limiter stiffness may result in increased response of the superstructure. Therefore, rational selection of the reserved gap and limiter stiffness is crucial to reduce the acceleration response.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.45-51
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• 1996

The combined shear and compression behaviors of seismic isolation rubber bearings are analyzed using the hyperelasticity material option of the ABAQUS computer program. The purpose of the analysis is to predict the behavior of laminated rubber bearing before the several tests. Some kinds of strain energy density functions are used as constitutive law for rubber itself having the hyperelasticity. The results are compared with test data peformed in Italy The analysis results show a little different with experimental results depending on the constitutive model and the refinement of finite element. The high order form of strain energy density functions results in good agreements and the mesh refinement above two for one rubber layer is enough to get good results.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1993년도 가을 학술발표회논문집
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• pp.186-192
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• 1993

Proto-type seismic isolation rubber bearings are investigated through nonlinear hyperelasticity finite elements using the ANSYS general purpose structural analysis code. The purpose of the analysis was to determine the maximum horizontal strain range which can be obtained with a 250KN hydraulic actuator. A Mooney-Rivlin strain energy density function was used as a constitutive law for rubber. The results are compared with the test data available in the literature and found to in good agreement only in the higy strain range. The analysis results can be used with conservatism to predict the necessary force required to a specified displacement such as the purpose of this analysis. However, more precise constitutive model will be required to simulate the bearing behavior with accuracy in the mid-range strain.

• 대한건축학회논문집:구조계
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• 제36권2호
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• pp.137-144
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• 2020

The purpose of this study is to experimentally evaluate the effect of improving seismic performance by applying the details of seismic reinforcement to the reinforced concrete frame with non-seismic details while maintaining the original opening shape. In this study, based on CF specimens with specific seismic details, a total of four full scale specimens were designed and fabricated. The main variables are the width and spacing of steel dampers installed in the upper and lower parts of seismic reinforcement details, and the presence or absence of torsion springs installed in the hinges. As a result of the test, it was evaluated to be helpful for seismic retrofit and opening isolation of steel dampers installed at the upper and lower parts of the seismic reinforcement details and torsion springs installed at the joints. In particular, CFR2S specimens with torsion springs showed the best performance in terms of strength, stiffness and energy dissipation capacity with increasing displacement angle.