• Title/Summary/Keyword: Kobe earthquake

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Evaluation of Caisson Quay Wall Behavior during the 1995 Kobe Earthquake by Nonlinear Effective Stress Analysis (비선형 유효응력해석을 이용한 1995 Kobe 지진시 케이슨 안벽의 거동 평가)

  • Lee, Jin-sun;Noh, Gyeong-do
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.6
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    • pp.401-412
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    • 2016
  • On Tuesday, January 17, 1995, an earthquake of magnitude 7.2 struck the Port of Kobe. In effect, the port was practically destroyed. After a hazard investigation, researchers reached a consensus to adopt a performance-based design in port and harbor structures in Japan. A residual displacement of geotechnical structures after an earthquake is one of the most important engineering demands in performance-based earthquake-resistant design. Thus, it is essential to provide reliable responses of geotechnical structures after an earthquake through various techniques. Today, a nonlinear explicit response history analysis(NERHA) of geotechnical structures is the most efficient way to achieve this goal. However, verification of the effective stress analysis, including post liquefaction behavior, is difficult to perform at a laboratory scale. This study aims to rigorously verify the NERHA by using well-defined field measurements, existing numerical tools, and constitutive models. The man-made, Port Island, in Kobe provides intensive hazard investigation data, strong motion records of 1995 Kobe earthquake, and sufficient engineering parameters of the soil. Two dimensional numerical analysis was conducted on the caisson quay wall section at Port Island subjected to the 1995 Kobe earthquake. The analysis result matches very well with the hazard investigation data. The NERHA procedure presented in this paper can be used in further studies to explain and examine the effects of other factors on the seismic behavior of gravity quay walls in liquefiable soil areas.

A Study on the Dynamic Behaviour of Composite Breakwaters Based on Dynamic Analysis Considering Effective Stresses (유효응력을 고려한 동해석을 통한 직립식 방파제의 동적 거동에 대한 연구)

  • Youngjin Jeon
    • Journal of the Korean GEO-environmental Society
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    • v.25 no.11
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    • pp.45-53
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    • 2024
  • In the current work, finite difference analysis was conducted by investigating the influence of dynamic analysis, considering effective stress, on the dynamic response of composite breakwaters. For comparison, the seismic behavior of breakwaters during the Kobe earthquake was analyzed, and performance-based seismic design was validated through centrifuge model test data, accompanied by a parametric study. The composite breakwaters damaged by the Kobe earthquake were verified through numerical analysis based on effective stress analysis, and validation of both centrifuge model tests and numerical analysis methods was conducted. The results of numerical analysis confirmed the seismic resistance based on the performance-based. And the results of analysis identified similar vertical displacement and liquefaction have confirmed through excess pore pressures. Also this study was conducted on the based on performance-based seismic deign, focusing on the results of acceleration, displacement, pore pressure, and liquefaction. Therefore the purpose of this study is to verify the results of pore pressure and liquefaction through the application and non-application of Finn model to compare the determination of liquefaction by the effective stress analysis.

Seismic Response Analysis of Computer Floors Using Base Isolation System (면진장치를 적용한 컴퓨터실 바닥의 지진응답해석)

  • 이경진
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.10a
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    • pp.424-431
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    • 2000
  • After the Kobe earthquake(1995) in Japan, the Izmit earthquake(1997) in Turkey and the Chi-chi earthquake(1999) in Taiwan, the small-to-medium-sized earthquakes occurred in the Koreans peninsula and this shows the fact that Korea is not located in the safety zone of earthquake. The main concept of base isolation system is to reduce the member forces by decreasing the earthquake forces transmitted to superstructure instead of the conventional techniques of strengthening the structural members. This study investigates the effect of seismic response attenuation of computer floors using base isolation systems

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Studies on Behavior Characteristics of Retrofitted Cut-and-Cover Underground Station Using Centrifuge Test Results (원심모형실험을 이용한 내진 보강된 개착식 지하역사의 거동특성 연구)

  • Kim, Jin-Ho;Yi, Na-Hyun;Lee, Hoo-Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.2
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    • pp.24-33
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    • 2017
  • Domestic urban railway underground station structures, which were built in the 1970s ad 1980s, had been constructed as Cut-and-Cover construction system without seismic design. Because the trends of earthquake occurrence is constantly increasing all over the world as well as the Korean Peninsula, massive human casualties and severe properties and structures damage might be occurred in an non-retrofitted underground station during an earthquake above a certain scale. Therefore, to evaluate the retrofit effect and soil-structure interaction of seismic retrofitted underground station, a centrifugal shaking table test with enhanced stiffness on its structural main member are carried out on 1/60 scaled model using the Kobe and Northridge earthquakes. The seismic retrofitted members, which are columns, side walls, and slabs, are evaluated to comparing with existing non-retrofitted centrifuge test results Also, to simulate the scaled ground using variation of shear velocity according to site conditions such as ground depth and density, resonant column test is performed. From the test results, the relative displacement behavior between ground and structures shows comparatively similar in ground, but is increased on ground surface. The seismic retrofit effects were measured using relative displacements and moment behavior of column and side walls rather than slabs. Additionally, earthquake wave can be used to main design factor due to large structural deformation on Kobe earthquake wave than Norhridge earthquake wave.

Post-Earthquake Damage Evaluation for R/C Buildings Based on Residual Seismic Capacity (지진피해를 받은 철근콘크리트 건물의 지진피해도 판정)

  • Lee Kang Seok;Kang Dae-Eon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.109-112
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    • 2005
  • In this paper described is the basic concept of the Guideline for Post-earthquake Damage Assessment of RC buildings, revised in 2001, in Japan. This paper discusses the damage rating procedures based on the residual seismic capacity index R, the ratio of residual seismic capacity to the original capacity, that is consistent with the Japanese Standard for Seismic Evaluation of Existing RC Buildings, and their validity through calibration with observed damage due to the 1995 Hyogoken-Nambu (Kobe) earthquake. Good agreement between the residual seismic capacity ratio and damage levels was observed.

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Study on Physical Characteristics of Historical and Artificial Ground Acceleration (역사지진 및 인공지진의 물리적 특성에 관한 연구)

  • 이대형;정영수;전환석
    • Journal of the Earthquake Engineering Society of Korea
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    • v.2 no.2
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    • pp.35-44
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    • 1998
  • Because of the continual occurrence of minor and moderate earthquakes in Korean peninsula, it is generally considered that Korean is not located in a safe region against probable earthquake any more, even though being recognized as a safe country in earthquake. It is in particular noted that nowadays there has been much concern about unexpected tragedy due to probable earthquake since the disaster of 1995 kobe earthquake. Thus, the objective of this research is to develop appropriate design spectrum which could be practicably used in seismic design of important structures taking into consideration of local physical characteristics. Particularly, we have to keep in mind the lessons from 1985 Mexico earthquake which had disregarded deep research on local ground conditions, being a possible magnification phenomena of ground motions in weak soil layer. Various spectra has been described based on the analysis of historical earthquakes, and generate the artificial ground acceleration. Also, rational numbers of artificial ground acceleration is investigated by the seismic analysis for skew slab bridges.

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Dynamic Characteristic Identification on Steel Column bases Installed in Pendulum-type Earthquake Response Observatory

  • Choi, Jae-Hyouk;Ohi, Kenichi
    • Journal of Mechanical Science and Technology
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    • v.18 no.12
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    • pp.2225-2235
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    • 2004
  • An observatory termed 'Steel Swing' has been developed, where a 15000 kg pendulum is hanged from a stiff steel frame. A building element can be tested after inserted between the pendulum and the frame. Free vibration, forced vibration tests and earthquake monitoring were performed on an exposed-type steel column base. The response records monitored during natural earthquakes were used to identify the vibration property of the specimen. Identified system gain was approximated by a theoretical gain of linear SDOF system, and the response calculated based on such a linear system agrees with the monitored response fairly well. This research technique can be applied to check the behaviors of new materials and new details of connections and the safety of non-structural elements as well.

The present state of earthquake hazard for the apartment structures in Korea (국내 공동주택의 지진위험도 현황에 관한 연구)

  • Kim, Hyeon-Jin;Park, Tae-Won;Jeong, Ran
    • Journal of the Korea Construction Safety Engineering Association
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    • s.49
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    • pp.92-102
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    • 2009
  • Earthquake is one of the hazard so hard because it is difficult predicted occurred time, scale and characters. Due to a recent Sichuan earthquake in China with a magnitude of 7.8, it is worried about having a major earthquake in Korea peninsula in near future. The earthquake in Kobe, Japan showed that the damages were concentrated on the buildings which were not considered to be protected from the earthquakes. In this study, apartment structures in Korea analyze about earthquake hazard and evaluate seismic performance. Through the this study we have notice of earthquake hazard for apartment structures which live a lot of population of Korea and suppose necessary for seismic retrofit.

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