• Title/Summary/Keyword: Earthquake analysis

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A Discussion on the Seismic Coefficient for Gravity Quay Wall Considering Frequency Characteristics of Input Earthquake (입력 지진의 주파수 특성을 고려한 중력식 안벽의 수평 지진계수에 대한 고찰)

  • Lee, Moon Gyo;Ha, Jeong Gon;Park, Heon Joon;Kim, Dong Soo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.1
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    • pp.15-22
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    • 2018
  • Pseudo-static approach has been conventionally applied for the design of gravity type quay walls. In this method, seismic coefficient ($k_h$), expressed in terms of acceleration due to gravity, is used to convert the real dynamic behavior to an equivalent pseudo-static inertial force for seismic analysis and design. Therefore, the calculation of an appropriate $k_h$ considering frequency characteristics of input earthquake is critical for representing the real dynamic behavior. However, the definitions of $k_h$, which is used for simplified analysis in Korea, focuses only on convenience that is easy to use, and the frequency characteristics of input earthquake are not reflected in the $k_h$ definitions. This paper evaluates the influences of the frequency characteristics of input earthquake on $k_h$ by initially reviewing the $k_h$ definitions in the existing codes of Japan for port structures and then by performing a series of dynamic centrifuge tests on caisson gravity quay walls of different earthquake input motions (Ofunato, Hachinohe). A review of the existing codes and guidelines has shown that the $k_h$ values are differently estimated according to the frequency characteristics of input earthquake. On the other hand, based on the centrifuge tests, it was found that the permanent displacements of wall are more induced when long-period-dominant earthquake is applied.

Comparative Analysis of Earthquake Management in Pohang and Japan (포항 지진과 일본 지진관리 업무 비교·분석)

  • Kim, Su Ran;Kim, Hye Won
    • Journal of the Earthquake Engineering Society of Korea
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    • v.22 no.3
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    • pp.193-199
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    • 2018
  • This study aims to create a disaster management system after an earthquake. Japan's earthquake disaster management system, including the Disaster Countermeasures Basic Act, addresses all of the disaster phases of prevention, mitigation, preparedness and emergency response as well as recovery and reconstruction with roles and responsibilities among the national and local governments clearly defined. Korea's earthquake disaster management system are including the Disaster Countermeasures Basic, but when the 9.12 earthquake occurred, problems such as insufficient early response, study on the earthquake lack were revealed. This study conducted a field survey and analyzed coping process after Po Hang earthquake. Therefore, this study have found that Disaster Management Headquarters are operated rapidly. They are coped with urgent safety inspection for damage facilities and soil liquefaction with advanced equipment. And The headquarters interviewed with victims. So they found out What the victims needed. However, when carrying out relief activities, Research of temporary housing and allocation of donations was not rapid. Further, this study have found that earthquake specialists were lack and disaster information transfer was not working. This study will be utilized as fundamental data in planning disaster management system after an earthquake.

Development of a Targeted Recommendation Model for Earthquake Risk Prevention in the Whole Disaster Chain

  • Su, Xiaohui;Ming, Keyu;Zhang, Xiaodong;Liu, Junming;Lei, Da
    • Journal of Information Processing Systems
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    • v.17 no.1
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    • pp.14-27
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    • 2021
  • Strong earthquakes have caused substantial losses in recent years, and earthquake risk prevention has aroused a significant amount of attention. Earthquake risk prevention products can help improve the self and mutual-rescue abilities of people, and can create convenient conditions for earthquake relief and reconstruction work. At present, it is difficult for earthquake risk prevention information systems to meet the information requirements of multiple scenarios, as they are highly specialized. Aiming at mitigating this shortcoming, this study investigates and analyzes four user roles (government users, public users, social force users, insurance market users), and summarizes their requirements for earthquake risk prevention products in the whole disaster chain, which comprises three scenarios (pre-quake preparedness, in-quake warning, and post-quake relief). A targeted recommendation rule base is then constructed based on the case analysis method. Considering the user's location, the earthquake magnitude, and the time that has passed since the earthquake occurred, a targeted recommendation model is built. Finally, an Android APP is implemented to realize the developed model. The APP can recommend multi-form earthquake risk prevention products to users according to their requirements under the three scenarios. Taking the 2019 Lushan earthquake as an example, the APP exhibits that the model can transfer real-time information to everyone to reduce the damage caused by an earthquake.

Effect of Vertical Ground Motion on Earthquake Response of Concrete Dams (콘크리트댐 지진응답에서의 수직 지반운동의 영향)

  • 이지호
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.04a
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    • pp.190-195
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    • 2001
  • In the present paper computational simulation of a concrete dam is performed to determine the effect of vertical ground motions on earthquake response of concrete dams. Cyclic and dynamic versions of the plastic-damage model proposed by Lee and Fenves are used to represent micro-crack development and crack opening/closing, which is important mechanism in nonlinear damage analysis of concrete structures subject to strong earthquake loading. The result shows that the vertical component of ground motion effects on final crack patterns and consequently, on displacement response.

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Review for Main Contents of Earthquake Resistance Design Regulations for Subway Structures (도시철도 내진설계기준 주요 내용 검토)

  • Yoo, Je-Nam;Lee, Sung-Min
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.468-474
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    • 2005
  • Recently 'Earthquake Resistance Design Regulations for Subway structures' has been established. It is the first time in our country. In this paper the regulations is reviewed and expalined briefly. Contents for the Performance Based Design Critetia and the estimation method for the design earthquake reponse spectrum in underground structures are reviewed. Earthquake resistance design for the evaluation of liquifaction, boundary spring coefficients for structural analysis modelling and soil response displacements are investigated and described also. Earthquake resitance design details shall be explained.

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Seismic characteristics of Tectonic Provinces of The Korean Peninsula (한반도 주요 지체구조구별 지진학적 특성)

  • 이기화
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1999.10a
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    • pp.64-71
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    • 1999
  • Seismicity of the Korean Peninsula shows intraplate seismicity that has irregular pattern in both time and space. Seismic data of the Korean peninsula consists of historical earthquakes and instrumental earthquakes. In this study we devide these data into complete part and incomplete part and considering earthquake size uncertainty estimate seismic hazard parameters - activity rate λ, b value of Gutenberg-Richter relation and maximum possible earthquake IMAX by statistical method in each major tectonic provinces. These estimated values are expected to be important input parameters in probabilistic seismic hazard analysis and evaluation of design earthquake.

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Earthquake Response Analysis of an Offshore Wind Turbine Considering Effects of Geometric Nonlinearity of a Structure and Drag Force of Sea Water (기하 비선형과 항력 효과를 고려한 해상풍력발전기의 지진 응답해석)

  • Lee, Jin Ho;Bae, Kyung Tae;Jin, Byeong Moo;Kim, Jae Kwan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.6
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    • pp.257-269
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    • 2013
  • In this study, the capability of an existing analysis method for the fluid-structure-soil interaction of an offshore wind turbine is expanded to account for the geometric nonlinearity and sea water drag force. The geometric stiffness is derived to take care of the large displacement due to the deformation of the tower structure and the rotation of the footing foundation utilizing linearized stability analysis theory. Linearizing the term in Morison's equation concerning the drag force, its effects are considered. The developed analysis method is applied to the earthquake response analysis of a 5 MW offshore wind turbine. Parameters which can influence dynamic behaviors of the system are identified and their significance are examined.

Appropriate Input Earthquake Motion for the Verification of Seismic Response Analysis by Geotechnical Dynamic Centrifuge Test (동적원심모형 시험을 이용한 부지응답해석 검증시 입력 지진의 결정)

  • Lee, Jin-Sun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.5
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    • pp.209-217
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    • 2013
  • In order to verify the reliability of numerical site response analysis program, both soil free-field and base rock input motions should be provided. Beside the field earthquake motion records, the most effective testing method for obtaining the above motions is the dynamic geotechnical centrifuge test. However, need is to verify if the motion recorded at the base of the soil model container in the centrifuge facility is the true base rock input motion or not. In this paper, the appropriate input motion measurement method for the verification of seismic response analysis is examined by dynamic geotechnical centrifuge test and using three-dimensional finite difference analysis results. From the results, it appears that the ESB (equivalent shear beam) model container distorts downward the propagating wave with larger magnitude of centrifugal acceleration and base rock input motion. Thus, the distortion makes the measurement of the base rock outcrop motion difficult which is essential for extracting the base rock incident motion. However, the base rock outcrop motion generated by using deconvolution method is free from the distortion effect of centrifugal acceleration.

Propose of Capacity Spectrum Method by Nonlinear Earthquake Response Analysis (질점계 비선형 지진응답해석에 의한 구조물의 역량스펙트럼 제안)

  • You, Jin-Sun;Yang, Won-Jik;Yi, Waon-Ho;Kim, Hyoung-Joon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.6
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    • pp.501-508
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    • 2014
  • In this paper, a method on deducing the capacity spectrum based on nonlinear earthquake response analysis will be introduced. Damage assessment of general building draws the capacity spectrum through the Push-over analysis and the intersection point of capacity spectrum and demand spectrum is seen as performance point. Push-over analysis is the way to perform static analysis by using the equivalent static load changed from the effect of earthquake and predict the behavior of structures by earthquake. But, this method can not be taken into account in the effects of higher mode and the dynamic characteristic. Therefore, in order to calculate the capacity spectrum under dynamic properties of building. A capacity spectrum from going ahead with the nonlinear earthquake response analysis is suggested.

Characteristics of Earthquake Responses of an Isolated Containment Building in Nuclear Power Plants According to Natural Frequency of Soil (지반의 고유진동수에 따른 면진 원전 격납건물의 지진응답 특성)

  • Lee, Jin Ho;Kim, Jae Kwan;Hong, Kee Jeung
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.6
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    • pp.245-255
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    • 2013
  • According to natural frequency of soil, characteristics of earthquake responses of an isolated containment building in nuclear power plants are examined. For this, earthquake response analysis of seismically isolated containment buildings in nuclear power plants is carried out by strictly considering soil-structure interactions. The structure and near-field soil are modeled by the finite element method while far-field soil by consistent transmitting boundary. The equation of motion of a soil-structure interaction system under incident seismic wave is derived. The derived equations of motion are solved to carry out earthquake analysis of a seismically isolated soil-structure system. Generally, the results of this analysis show that seismic isolation significantly reduces the responses of the soil-structure system. However, if the natural frequency of the soil is similar to that of the soil-structure system, the responses of the containment buildings in nuclear power plants rather increases due to interactions in the system.