• 제목/요약/키워드: great earthquake

검색결과 176건 처리시간 0.022초

Seismic response of spring-damper-rolling systems with concave friction distribution

  • Wei, Biao;Wang, Peng;He, Xuhui;Jiang, Lizhong
    • Earthquakes and Structures
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    • 제11권1호
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    • pp.25-43
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    • 2016
  • The uneven distribution of rolling friction coefficient may lead to great uncertainty in the structural seismic isolation performance. This paper attempts to improve the isolation performance of a spring-damper-rolling isolation system by artificially making the uneven friction distribution to be concave. The rolling friction coefficient gradually increases when the isolator rolls away from the original position during an earthquake. After the spring-damper-rolling isolation system under different ground motions was calculated by a numerical analysis method, the system obtained more regular results than that of random uneven friction distributions. Results shows that the concave friction distribution can not only dissipate the earthquake energy, but also change the structural natural period. These functions improve the seismic isolation efficiency of the spring-damper-rolling isolation system in comparison with the random uneven distribution of rolling friction coefficient, and always lead to a relatively acceptable isolation state even if the actual earthquake significantly differs from the design earthquake.

파랑하중 및 지진하중을 받는 Steel Jacket의 동적해석 (Dynamic Analysis of the Steel Jacket under Wave Force and Earthquake Force)

  • 김문영
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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    • pp.284-291
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    • 1999
  • The reliability analysis is of great importance in their design since offshore towers are high-cost and high-risk structures. The design of platforms in the marine environment depends on results of the dynamic behavior of the structure during earthquakes and storm wave conditions. this paper presents results of an analytical study on evaluating dynamic response of steel jacket modelled by space frame elements. program $\boxDr$OFSPC$\boxUl$for the linear and nonlinear dynamic analysis of steel jacket platform has been developed using FORTRAN 90 programing language through the present study. Free vibration and dynamic behavior of steel jackets under regular and irregular wave and earthquake force are investigated using this program

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경사지반에서 SASW기법 적용시 수치해석을 이용한 영향요소 연구 (Numerical Studies for Application of the SASW Method in an Inclined Soil Layer)

  • 김동수
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2001년도 춘계학술대회 논문집
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    • pp.108-119
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    • 2001
  • The Spectral Analysis of surface Waves(SASW) Method has a great has a great potential for rapid determination of shear wave velocity profile of ground. However, it has an inherent limitation in the interpretation of test results due to the assumption that the ground is layered horizontally. The reason of the assumption is that difficulties exist in obtaining analytical solutions of wave equation when a soil system is composed of inclined soil layer. In this study, a finite-element method has been employed to assess the effects of dip angle and stiffness contrast of inclined soil layers and the testing direction on the dispersion curve. The propagation of wave front in the inclined soil layer was also investigated. The results indicated that the influence of dip angle on the dispersion curve is getting obvious as the dip angle increases and the propagation of wave front in the inclined layer also entirely different compared with the case of the horizontal layer.

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지반거동의 지속시간이 건물에 미치는 영향 (Duration Effect of the Ground Motion on Structures)

  • 김희철
    • 전산구조공학
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    • 제5권1호
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    • pp.91-96
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    • 1992
  • 내진구조는 건축규준에 의하여 강제성을 띤 이후 많은 발전을 하였으나 아직도 완전하게 이해되지는 않고 있다. 본 논문은 실제로 발생하였던 두 지진의 지반운동을 10층의 철골조에 적용시켜 얻은 결과를 비교하였다. 1989년 California의 Loma Prieta에서 발생한 규모 7.1의 지진기록 12세트와 1985년 Chile의 Valparaiso에서 발생한 규모 7.8의 지진기록 9세트를 UBC의 지진지역 2B에 알맞게 조절하였다. 비슷한 규모를 가진 두 지진의 지반변위를 건물에 직접 적용시켜서 비교한 결과 그 지속시간이 긴 Chile지진이 상대적으로 지속시간이 짧은 California지진보다 약 2배 정도 큰 영향을 건물에 미치는 것이 발견되었다. 내진구조의 설계에 있어서 최대지반운동과 더불어 지반운동의 지속시간도 매우 중요하게 고려되어야 할 사항이다.

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Earthquake behavior of M1 minaret of historical Sultan Ahmed Mosque (Blue Mosque)

  • Kocaturk, Turgut;Erdogan, Yildirim Serhat
    • Structural Engineering and Mechanics
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    • 제59권3호
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    • pp.539-558
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    • 2016
  • Minarets are almost the inevitable part of Mosques in Islam and according to some, from a philosophical point of view, today they symbolize the spiritual elevation of man towards God. Due to slenderness, minarets are susceptible to earthquakes and wind loads. They are mostly built in a masonry style by using cut limestone blocks or occasionally by using bricks. In this study, one minaret (M1 Minaret) of one of the charmest mosques of Turkey, Sultan Ahmed Mosque, popularly known as Blue Mosque, built between 1609 and 1616 on the order of Sultan Ahmed by the architect Mehmet Agha is investigated under some registered earthquake loads. According to historical records, a great earthquake hit Istanbul and/or its close proximity approximately every 250 years. Ottomans tackled with the problem of building earthquake resistant, slender minarets by starting to use forged iron connectors with lead as a filler to fix them to the upper and lower and to adjacent stones instead of using traditional mortar only. Thus, the discrete stones are able to transfer tensile forces in some sense. This study investigates the contribution of lead to the energy absorption capacity of the minaret under extensive earthquakes occurred in the region. By using the software ANSYS/LS-DYNA in modelling and investigating the minaret nonlinearly, it is found out that under very big recorded earthquakes, the connectors of vertical cast iron-lead mechanism play very important role and help to keep the structure safe.

능력스펙트럼법을 이용한 비정형 건축구조물의 2차원 지진성능평가 방법 연구 (Study on 2-D Seismic Evaluation of Asymmetric Buildings Using Capacity Spectrum Method)

  • 김상호;이한선
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2001년도 춘계학술대회 논문집
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    • pp.296-303
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    • 2001
  • In the evaluation of asymmetric buildings, torsional effects should be considered by three-dimensional analysis. However, this analysis is time-consuming and requires great efforts. The goal of this study is to give a comprehensible and simple procedure in the seismic evaluation by using two-dimensional analysis of asymmetric buildings so that practicing engineers can easily adapt it to their work.

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