• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.37-46
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• 2006

In this study, the efficacy of the newly developed smart passive control system to improve seismic performance of base isolated building structures is numerically verified. The smart passive control system consists of a magnetorheological (MR) damper and an electromagnetic induction (EMI) part. The damping characteristics of an MR damper can be controlled by the current generated in an EMI part according to the Faraday's law of electromagnetic induction. An EMI part consisting of a permanent magnet and a solenoid coil could substitute a control system including sensors, a controller and an external power supply in a conventional smart control system. The benchmark control problem for a base isolated building presented by the american society of civil engineers is considered for numerical simulation. The control performance of the smart passive control system is compared to that of the conventional smart control system using MR dampers. It is demonstrated from the numerical simulation results that the smart passive control system is useful to improve the seismic performance of base isolated buildings.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.55-66
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• 2005

The effectiveness of fuzzy supervisory control technique for the control of seismic responses of smart base isolation system is investigated in this study. To this end, first generation base isolated building benchmark problem is employed for the numerical simulation. The benchmark structure under consideration is an eight-story base isolated building having irregular plan and is equipped with low-damping elastometric bearings and magnetorheological (MR) dampers for seismic protection. Lower level fuzzy logic controllers (FLC) for far-fault or near-fault earthquakes are developed in order to effectively control base isolated building using multi-objective genetic algorithm. Four objectives, i.e. reduction of peak structural acceleration, peak base drift, RMS structural acceleration and RMS base drift, are used in multi-objective optimization process. When earthquakes are applied to benchmark building, each of low level FLCs provides different command voltage and supervisory fuzzy controller combines two command voltages io one based on fuzzy inference system in real time. Results from the numerical simulations demonstrate that base drift as well as superstructure responses can be effectively reduced using the proposed supervisory fuzzy control technique.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.6
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• pp.1-6
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• 2002

In order to apply seismic isolators to low-cost buildings, seismic isolators have to be low-cost and light. In this paper fiber reinforced strip form isolator in which the steel plates of conventional rubber bearing were replaced by fiber was proposed. The proposed fiber reinforced strip form isolator was designed, fabricated, cut and subjected to vertical test and horizontal test. Therefore, fiber reinforced strip form isolator was to be shown valid in the view point of fabrication and application to desired size. The horizontal test and vertical test have shown that fiber reinforce strip form isolator could be replaced the rubber isolator. By these results, low-cost and light seismic isolator can be applied to the low-cost building.

• Journal of the Korea Concrete Institute
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• v.17 no.6 s.90
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• pp.975-982
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• 2005

Scientific community agrees about the fact that base Isolation provides interesting solutions to minimize the seismic risk. Reliability of such a technique is nowadays proofed by a large number of applications like public buildings, nuclear plants, bridges, etc. This paper reports the results of performance verification tests of the base isolated RC building with the laminated rubber bearings which is manufactured by enterprise in Korea. The shaking table tests were performed using a three story model scaled to 1/3 of the prototype RC apartment building. Several major earthquake records were scaled to different peak ground accelerations and used as input base excitations. Especially in this study, effect of earthquake characteristics on response reduction and effect of the intensity of excitations are studied. Through the verification tests, the validity of the applied base isolaion device and the response reduction effect against earthquakes are confirmed.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.349.2-349
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• 1999

• Land and Housing Review
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• v.2 no.3
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• pp.287-297
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• 2011

This paper presents the results of performance verification tests of the isolated flat plate apartment building with the laminated rubber bearings. The shaking table test is carried out in CABR(China Academy of Building Research) with two 1/10 scale isolation and non-isolation models under 4 excitation waves. The shaking table test is proceeding from x axis, y axis and x+y axis with different amplitude of acceleration values. The results show that, to non-isolated model, the natural vibration period is remarkably decreased and entered non-linear condition after moderate earthquake. Its accelerations become lager with increasing storey number and completely collapsed under large earthquake. The inter-storey shifts largely exceed the limit values of regulated displacement angles. But to isolated model, the natural vibration period of isolated modal is almost the same in all conditions and still in its elastic condition. The earthquake loading is greatly reduced and the accelerations of superstructure are greatly reduced. The inter-storey drifts are very small and can be neglected. The isolated model is in translational state and can be seen as a rigid whole. The displacements of isolation layer are in the allowable range. This experiment demonstrates that the seismic isolation is very effective to mitigate the influence of earthquake on structures and it is possible to increase the serviceability due to decrease the floor acceleration. facilities from their good states that is superior to non-isolated structure.

• Journal of Korean Association for Spatial Structures
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• v.10 no.3
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• pp.49-56
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• 2010

In this study, the control performance of a smart top-story isolation system for tall buildings subjected to wind excitation was investigated. To this end, a 77-story tall building structure was employed and wind loads obtained from wind tunnel test were used for numerical simulations. The top-story of an example structure is separated from the main structure by a smart base isolation system composed of friction pendulum systems (FPS) and MR dampers. The primary purpose of the smart top-story isolation system is to mitigate the dynamic responses of the main structure, but the excessive movement of the isolated top story may cause the unstableness of the building structure. Therefore, the skyhook control algorithm was used to effectively reduce both responses of the isolated top story and the main structure. The control performance of the proposed smart top-story isolation system was investigated in comparison with that of the passive top-story isolation system. It has been shown from numerical simulation results that the smart top-story isolation system can effectively reduce wind-induced responses of the example building structure compared to the passive top-story isolation system with reduction of the top-story movement.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.1
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• pp.39-48
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• 2022

In earthquake situations, broadcasting and communication services are directly linked to rapid on-site rescue and effective restoration works. Recently, a variety of base isolation devices are widely introduced on building floors to avoid critical seismic damages of telecommunication facilities. However, in buildings with long fundamental periods, those devices may have undesirable amplification of seismic responses due to resonance effect between the building floors and base isolation devices. This study performs the seismic safety evaluation of two types of base isolation devices deployed for telecommunication facilities in mid- and high-rise buildings through numerical and experimental approaches. It is found that mid- and high-rise buildings can have low-frequency dynamic responses at the top floor when being subjected to design basis earthquake loading. Furthermore, bi-directional shake table testing demonstrated that the selected base isolation devices can exhibit unstable dynamic behaviors under such low-frequency excitations of the floor.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.903-908
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• 1998

KALIMER 원자로 건물에 대하여 3차원 쉘요소 모델과 단순 빔모델을 작성하고 고유진동수 해석을 수행하였다. 두 모델의 1차 수평방향 고유진동수는 대체로 일치하였다. 단순 빔모델에 대해 원자로건물의 회전 관성모멘트를 해석에 반영한 경우 3차원 모델에는 없는 회전모드가 발생되었다. 지진응답해석은 1940 EL Centro와 인공지진에 대하여 수행하였으며, 두 결과는 면진구조물의 경우 비면진구조물과 비교하여 응답가속도가 크게 줄고, 상대변위가 증가하는 경향을 보였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.392-397
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• 1996

지반특성에 따라 지진발생시 면진구조물과 비면진 구조물의 응답특성이 어떠한가를 평가하기위해, 1940 El Centro 지진을 입력지진으로 하고, 면진구조물로는 가압경수형 원자로격납건물을 이용하여 수평(NS) 및 수직지진입력에 대한 시간이력해석을 수행하였다. 0.5Hz 수평면진 구조물의 경우 수평방향 가속도응답은 지반특성에 무관하게 거의 변화가 없으며, 또 2Hz 이상에서 비면진구조물의 수평지진가속도응답보다 현저히 낮은 가속도응답을 갖는다. 면진베어링의 수직방향 21Hz 고유진동수는 풍화암의 경우 수직방향 가속도응답에 영향을 주지 않으나. 경암의 경우 원자로지지점에서의 수직방향 가속도응답을 전반적으로 증가시킨다. 비면진 구조물의 경우 지반의 강성이 약할수록 가속도응답이 비교적 큰 폴라크레인위치에서 수평 및 수직방향 가속도응답이 감소되는 것으로 나타났으며, 특히 수직방향의 가속도응답이 크게 감소하는 것으로 나타났다.