• 제목/요약/키워드: seismic isolation systems

검색결과 187건 처리시간 0.025초

탄성체 적층 납삽입 제진장치의 설계 및 특성시험 (An Experimental Study and the Design of the Rubber Laminated Lead Damper)

  • 이완하;박진영;박정우;김기만;박건록
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2011년도 춘계학술대회 논문집
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    • pp.165-170
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    • 2011
  • A large number of seismic isolation systems have been developed since the early 1970s. They are basically a combination of elastomeric bearing and energy dissipators. The investigation described in this paper analyzes shear property and the frequency dependence of Lead Rubber Damper(LRD). Lead Rubber Damper is similar in shape and performance property to Lead Rubber Bearing. Experimental condition ranges from 20 to 200% in share strain and from 0.1 to 1.0Hz in frequency. When the shear strain is increased, effective stiffness and damping ratio are decreased. When the frequency is increased, change of the behavior characteristic is subtle.

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면진용 고무 베어링의 안정성 해석 (Stability Analysis of Rubber Bearings for Seismic Isolation)

  • 이종세;오종원
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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    • pp.423-430
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    • 1998
  • Elastomeric bearings are frequently used as a means to isolate structural systems from earthquake loadings. The combination of rubber layers and reinforcing steel shims makes the bearings stiff axially but soft laterally The shear flexibility of these short columns can lead to relatively low buckling loads which may be further reduced when high shear strains are simultaneously imposed. The area reduction formula has been proposed to account for the reduction in buckling load due to shear. The result obtained from the formula is presumed to be conservative but the degree of conservatism is unknown. This paper describes a numerical study which aims at determining the effect of high shear strain on the critical load of rubber bearings. The results from the finite element analysis which accounts for both the material and geometric non-linearities are compared against the theoretical results in order to examine the validity of the theoretical formulas.

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자력을 이용한 마찰진자 베어링의 면진성능 (Base Isolation Performance of Friction Pendulum System using Magnetic Force)

  • 황인호;신호재;이종세
    • 한국지진공학회논문집
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    • 제12권4호
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    • pp.55-61
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    • 2008
  • 면진장치 중에서 최근 많은 연구가 이루어지고 있는 마찰진자 베어링은 적절한 마찰력을 얻기 위해 PTFE(Polytetrafluoroethylene) 마찰재가 이용되고 있다. 본 연구에서는 자력의 반발력을 이용해 재료의 성질을 대체하여 면진성능을 향상 시킬 수 있는 자력을 이용한 마찰진자 베어링을 제안하였다. 제안된 시스템은 자력에 의한 반발력이 수직력을 줄여줌으로써 재료에 의한 마찰계수의 영향을 줄일 수 있음을 가정하였다. 또한 자력의 영향을 가정하기 위해서 간단한 실험을 구성해 보았으며, 자력이 작용을 할 때 마찰계수($\mu$)를 약 20%정도 줄여줄 수 있었다. 실험 결과를 적용한 수치해석을 통해 다양한 지진에 대해서 기존의 마찰진자 베어링보다 향상된 성능을 보여주었고, 특히 지진으로 인해 구조물의 파괴에 작용하는 주된 요소인 최상층의 가속도와 구조물의 상대변위를 비교함으로써 제안된 시스템이 면진장치로서의 기능을 가지고 있음을 확인하였다. 자력을 이용하여 기존의 PTFE 마찰재를 대체할 수 있는 자력을 이용한 마찰진자 베어링의 구조적 설계를 할 수 있다면 마찰진자 베어링의 문제점을 보완한 기초격리장치로서 적용될 수 있을 것으로 사료된다.

MR 감쇠기와 FPS를 이용한 하이브리드 면진장치의 퍼지제어 (Fuzzy control of hybrid base-isolator with magnetorheological damper and friction pendulum system)

  • 김현수
    • 한국지진공학회논문집
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    • 제9권1호통권41호
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    • pp.61-70
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    • 2005
  • 본 연구에서는 하이브리드 면진장치가 설치된 단자유도 구조물에 대하여 진동대 실험을 수행하였다. 본 연구에서 사용된 하이브리드 면진장치는 네 개의 FPS와 한 개의 MR 감쇠기로 구성하였다. 다양한 크기 및 특성을 가진 지진하중을 하이브리드 면진장치가 설치된 구조물에 가하여 진동제어 성능을 평가하였다. 본 연구에는 준능동 MR 감쇠기의 저항력을 효과적으로 조절하기 위하여 퍼지제어기를 사용하였고 구조물에 부착된 계측기를 통하여 변위 및 가속도를 피드백으로 이용한다. 수동 및 준능동 제어기법을 사용하여 얻은 구조물의 응답을 서로 비교하였고 그 결과 FPS와 MR 감쇠기의 조합으로 다양한 특성의 하중을 받는 구조물의 진동제어를 효과적으로 수행할 수 있음을 알 수 있다.

Depiction of concrete structures with seismic separation under faraway fault earthquakes

  • Luo, Liang;Nguyen, Hoang;Alabduljabbar, Hisham;Alaskar, Abdulaziz;Alrshoudi, Fahed;Alyousef, Rayed;Nguyen, Viet-Duc;Dang, Hoang-Minh
    • Advances in concrete construction
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    • 제9권1호
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    • pp.71-82
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    • 2020
  • One of the most suitable methods in structural design is seismic separator. Lead-Rubber Bearing (LRB) is one of the most well-known separation systems which can be used in different types of structures. This system mitigates the earthquake acceleration prior to transferring to the structure efficiently. However, the performance of this system in concrete structures with different heights have not been evaluated thoroughly yet. This paper aims to evaluate the performance of LRB separation system in concrete structures with different heights. For this purpose, three, 16, and 23 story concrete structures are equipped by LRB and exposed to a far-field earthquake. Next, a time history analysis is conducted on each of the structures. Finally, the performance of the concrete structures is compared with each other in the term of their response to the earthquakes and the formation of plastic hinges. The results of the paper show that the rate of change in acceleration response and the ratio of drift along the height of 8 and 23 stories concrete structures are more than those of the 16-stories, and the use of LRB reduces the formation of plastic joints.

Regularized model-free adaptive control of smart base-isolated buildings

  • Alvaro Javier Florez;Luis Felipe Giraldo;Mariantonieta Gutierrez Soto
    • Smart Structures and Systems
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    • 제34권2호
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    • pp.73-85
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    • 2024
  • Smart base-isolated buildings rest on flexible pads known as base isolators that minimize the effect of external disturbances along with active/semi-active actuators. The strategies used to control these active components are typically based on system models that are known a priori. Although these models describe some of the most important dynamics of the elements involved in the system, the high degree of uncertainty in the behavior of a structure under external disturbances is very difficult to characterize using a fixed model. In this work, we propose a strategy that deals with this issue: the input that controls the actuator in the base isolation system results from the compound action of a controller that relies on a model of the system that is known a priori, and a control policy that is designed based on online data-driven inferences on the behavior of the system. In this way, the control design process incorporates both the prior information about the system and the unknowns of the system, such as non-modeled parameters and nonlinear behaviors in the building. We show through simulations the performance of the proposed method in an eight-story building subjected to seismic loading.

Paleo-Tsushima Water influx to the East Sea during the lowest sea level of the late Quaternary

  • Lee, Eun-Il
    • 한국지구과학회지
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    • 제26권7호
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    • pp.714-724
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    • 2005
  • The East Sea, a semi-enclosed marginal sea with shallow straits in the northwest Pacific, is marked by the nearly geographic isolation and the low sea surface salinity during the last glacial maximum (LGM). The East Sea might have the only connection to the open ocean through the Korea Strait with a sill depth of 130 m, allowing the paleo-Tsushima Water to enter the sea during the LGM. The low paleosalinity associated with abnormally light $\delta^{18}O$ values of planktonic foraminifera is interpreted to have resulted from river discharge and precipitation. Nevertheless, two LGM features in the East Sea are disputable. This study attempts to estimate volume transport of the paleo-Tsushima Water via the Korea Strait and further examines its effect on the low sea surface salinity (SSS) during the lowest sea level of the LGM. The East Sea was not completely isolated, but partially linked to the northern East China Sea through the Korea Strait during the LGM. The volume transport of the paleo-Tsushima Water during the LGM is calculated approximately$(0.5\~2.1)\times10^{12}m^3/yr$ on the basis of the selected seismic reflection profiles along with bathymetry and current data. The annual influx of the paleo-Tsushima Water is low, compared to the 100 m-thick surface water volume $(about\;79.75\times10^{12}m^3)$ in the East Sea. The paleo-Tsushima Water influx might have changed the surface water properties within a geologically short time, potentially decreasing sea surface salinity. However, the effect of volume transport on the low sea surface salinity essentially depends on freshwater amounts within the paleo-Tsushima Water and excessive evaporation during the glacial lowstands of sea level. Even though the paleo-Tsushima Water is assumed to have been entirely freshwater at that time period, it would annually reduce only about 1‰ of salinity in the surface water of the East Sea. Thus, the paleo-Tsushima Water influx itself might not be large enough to significantly reduce the paleosalinity of about 100 m-thick surface layer during the LGM. This further suggests contribution of additional river discharges from nearby fluvial systems (e.g. the Amur River) to freshen the surface water.