• The Journal of Engineering Geology
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• v.5 no.1
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• pp.45-58
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• 1995

A probabilistic seismic risk in the Korean Peninsula is calculated from the instrumental eaathquake data. For the purpose, an instrumental earthquake catalogue since 1905 m which parameters are readjusted to have uniformity and homogeneity in description is cornpiled through the review of all available data. The maximum potential earthquake expected in the Korean Peninsula for 100, 1000, and 4000 years are estimated to be 6.3, 7.2 and 7.8 in magnitude, respectively, from Gumbel's extreme value theory. In addition, contour rnaps representing the maximum ground acceleration expected for 100 and 1000 years are prepared using the return period method. Seismic hazart] curves in which maximum ground acceleration expressed in terms of probability of occurrence are also presented for the major populated areas.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.25-33
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• 2006

The purpose of this study is to develop the curve fitted equations for practicality and actual calculation during seismic performance evaluation of buried pipelines. Curve fitting for strain curve according to the wavelength of the seismic wave was produced using the non-linear least square method and the equations with the best results was suggested. In addition, a degree and coefficient of polynomial fitting equation needed to use curve fitted equation were identified. Interpreting process during the test of resistance of earthquake of buried pipelines with various end boundary conditions were provided through example questions. The results of this study were used to conduct a dynamic response analysis and a seismic performance evaluation of concrete, steel, and FRP pipes with various end boundary conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.155-162
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• 2006

This study presents the seismic risk assesment for an extradosed bridge with seismic isolators of lead rubber bearings(LRB). First, the seismic vulnerability of a structure and then the seismic hazard of the site are evaluated using earthquake data set and seismic hazard map in Korea, and then the seismic risk of the structure is assessed. The nonlinear seismic analyses are carried out to consider plastic hinges of bridge columns and nonlinear characteristics of soil foundation. The ductility demand is adopted to describe the nonlinear behavior of a column, and the moment-curvature curve of a column is assumed to be bilinear hysterestic. The fragility curves are represented as a log-normal distribution function for column damage, movement of superstructure, and cable yielding. And seismic hazard is estimated using the available seismic hazard maps. The results show that the effectiveness of the seismic isolators for the columns is more noticeable than those for cables and girders, in seismic isolated extradosed bridges under earthquakes.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.5
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• pp.371-380
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• 2017

The risk-targeted seismic design concept was first included in ASCE/SEI 7-10 to address problems related to the uniform-hazard based seismic concept that has been constructed without explicitly considering probabilistic uncertainties in the collapse capacities of structures. However, this concept is not yet reflected to the current Korean building code(KBC) because of insufficient strong earthquake data occurred at the Korean peninsula and little information on the collapse capacities of structures. This study evaluates the risk-targeted seismic performance of steel ordinary concentrically braced frames(OCBFs). To do this, the collapse capacities of prototype steel OCBFs are assessed with various analysis parameters including building locations, building heights and soil conditions. The seismic hazard curves are developed using an empirical spectral shape prediction model that is capable of reflecting the characteristics of earthquake records. The collapse probabilities of the prototype steel OCBFs located at the Korean major cities are then evaluated using the risk integral concept. As a result, analysis parameters considerably influence the collapse probabilities of steel OCBFs. The collapse probabilities of taller steel OCBFs exceed the target seismic risk of 1 percent in 50 years, which the introduction of the height limitation of steel OCBFs into the future KBC should be considered.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.6
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• pp.47-53
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• 2008

This research focuses on the issue of seismic retrofit prioritization based on the Caltrans' highway network serving Los Angeles and Orange counties. Retrofit prioritization is one of most important problems in earthquake engineering, and it is a problem that most decision makers face in the process of resource allocation. This study demonstrates the methods of prioritized resource allocation in the process of retrofitting a regional highway network. For the criteria of a retrofit ranking, seismic vulnerability and the importance of network link are first introduced. Subsequently, link-based seismic retrofit cases are simulated, investigating the effects of the seismic retrofit in terms of seismic performance, such as driver's delay. In this study, probabilistic scenario earthquakes are used to perform a probabilistic seismic risk analysis. The results show that the retrofit prioritization can be differently defined and ranked depending on the stakeholders. This study provides general guidelines for prioritization strategy for the effective retrofitting of a highway network system.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1997.11a
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• pp.15-24
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• 1997

최근 우리나라에도 많은 지진사례가 보고되고 있으며, 이러한 지진하중은 원전설비 및 각종 기계설비등의 가동중 파손을 유발시킬 수 있는 잠재적 위험성이 높다. 이에 지진하중에 대한 안전성 확보의 필요성이 점차 대두되고 있다. 지진하중은 종ㆍ횡파에 의한 인장ㆍ압축이 반복되는 역사이클하중(reverse cyclic loading)형태로, 현재까지는 이를 고려한 설계개념이 미흡한 실정이며 이에 대한 파괴물성치의 확보는 물론 파괴물성치 평가 절차도 확립되어 있지 않은 상태이다. 따라서 지진하중에 대한 안전성확보를 위해서는, 역사이클 하중이 재료의 파괴특성 특히, 파괴저항(J-R)곡선에 미치는 영향이 고찰되어야 할 것이다. (중략)

• Journal of the Korean GEO-environmental Society
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• v.19 no.10
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• pp.13-19
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• 2018

Following the 2016 Gyeongju earthquake, the Pohang Earthquake occurred in 2017, and the south-east region in Korea is under the threat of an earthquake. Especially, in the Pohang Earthquake, the liquefaction phenomenon occurred in the sedimentation area of the coast, and preparation of countermeasures is very important. The soil liquefaction can affect the underground facilities directly as well as various structures on the ground. Therefore, it is necessary to identify the liquefaction risk of facilities and the structures against the possible earthquakes and to prepare countermeasures to minimize them. In this study, we investigated the seismic liquefaction risk about the electric power utility tunnels in the southeast area where the earthquake occurred in Korea recently. In the analysis of seismic liquefaction risk, the earthquake with return period 1000 years and liquefaction potential index are used. The liquefaction risk analysis was conducted in two stages. In the first stage, the liquefaction risk was analyzed by calculating the liquefaction potential index using the ground survey data of the location of electric power utility tunnels in the southeast region. At that time, the seismic amplification in soil layer was considered by soil amplification factor according to the soil classification. In the second stage, the liquefaction risk analysis based on the site response analyses inputted 3 earthquake records were performed for the locations determined to be dangerous from the first step analysis, and the final liquefaction potential index was recalculated. In the analysis, the site investigation data were used from the National Geotechnical Information DB Center. Finally, it can be found that the proposed two stage assessments for liquefaction risk that the macro assessment of liquefaction risk for the underground facilities including the electric power utility tunnel in Korea is carried out at the first stage, and the second risk assessment is performed again with site response analysis for the dangerous regions of the first stage assessment is reasonable and effective.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.57-65
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• 2009

This study is an evaluation of seismic fragility function using the HAZUS program for railway bridge systems, based on the results of previous research on seismic safety factor. First, a fragility function for each of the bridge members was evaluated according to the damage criteria and failure mode. Subsequently, bridge system fragility was evaluated using a fault tree to describe damage status. Finally, a fragility evaluation method for the bridge system was developed, based on the safety factor derived from the previous research.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.535-542
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• 2023

In order to understand the seismic performance of a bridge, it is common to review through seismic performance evaluation and numerical analysis of the target bridge. Seismic performance evaluation and review through numerical analysis are analysis methods for specific target bridges, and many problems can arise in each management body managing bridges nationwide. Therefore, in this study, research was conducted to estimate the seismic performance of public bridges with various types and characteristics. Seismic performance was estimated by applying the seismic risk assessment method, calculating the seismic fragility curve for the type and specifications of the bridge, and estimating the seismic performance of the bridge in use by applying the domestic seismic design standard. In addition, by installing it on the platform, service items were established so that users can easily review the estimation of seismic performance of domestic bridges.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.368-368
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• 2020

최근 초대형화 되어 나타나고 있는 이상홍수와 지진 등에 의한 저수지 붕괴와 같은 대규모 비상상황 발생으로 하류지역 주민의 생명과 재산의 피해가 발생하고 있다. 국내의 경우 1996년 이후로 지속적으로 발생하고 있는 이상홍수로 인해 1998년에는 40개,1999년에는 5개의 소규모 저수지가 붕괴되었으며 최근 2013년과 2014년에도 저수지가 붕괴되는 상황이 발생했다. 댐붕괴의 원인은 구조물의 자연적 노화, 극심한 강우나 홍수, 지진, 제체전도, 파이핑, 침윤발생, 월류 및 파랑 등에 의한 자연적 상황 등이 요인이 될 수 있으며, 시공결함, 사고 또는 전쟁과 같은 인위적인 요인으로 발생할 수도 있다. 과거에 설계 및 시공기술이 부족하였거나 경제적인 이유로 부실하게 건설되어 있는 댐이 세계적으로 산재되어 있어 잠재적인 위험을 상당수 내재하고 있는 실정이다. 본연구는 댐의 점진적인 파괴에 의해 발생하는 유출수문곡선을 구하고 파괴의 성질을 예측 및 홍수파를 수리학적으로 추적하기위해 BREACH 모형과 DAMBRK 모형을 사용했으며 극한홍수(PMF)조건과와 최대지진발생(MCE)조건을 적용하여 원주시 관내 저수지 붕괴 모의 시나리오를 구축했다. 저수지 붕괴에 따른 유출수문곡선을 유도하기 위해서 본 연구에서는 기존의 EAP보고서 자료를 참고하여 붕괴지속시간, 붕괴부 평균폭, 붕괴부 측벽면 경사의 변화에 따라 다양한 모의를 수행함으로써 발생되는 붕괴부 유량 수문곡선을 도출하여 각각의 조건들이 붕괴파 형성에 미치는 영향에 대한 분석을 실시하였다. 그 결과 저수지의 붕괴시 첨두유출량에 민감한 영향을 주는 인자는 붕괴지속시간과, 붕괴부 평균폭으로서 이들 값이 붕괴유출량 변화에 많은 영향을 주는 것으로 나타났다. 최대지진발생(MCE)조건 해석결과 홍수류의 범람으로 인해 홍수파가 하류측으로 진행할수록 완만히 감소하며, 하천 중·상류부 인근 제내지로 홍수류의 범람이 발생하는 것으로 검토되었으며, 극한홍수(PMF)조건 해석결과 최대지진발생(MCE)조건과 같이 홍수파가 하류측으로 진행할수록 완만히 감소하는 특성을 보이며, 하천 전체 구간에서 인근제내지로 홍수류의 범람이 발생하는 것으로 검토되었다. 본 연구는 침수구역 피해규모 산정 및 비상대처계획도를 작성시 기초데이터가 되어 상황별 피해예상지역에 대해 응급행동요령, 주민대피계획비상대처계획을 수립하여 지역 주민생활에 안정을 기여하고자 한다.