• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.6 s.40
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• pp.31-43
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• 2004

Seismic risk assessment of bridge is presented using fragility curves which represent the probability of damage of a structure virsus the peak ground acceleration. In theseismic fragility analysis, the structural damage is defined using the rotational ductility at the base of the bridge pier, which is obtained through nonlinear dynamic analysis for various input earthquakes. For the assessment of seismic risk of bridge, peak ground accelerations are obatined for various return periods from the seismic hazard map of Korea, which enables to calculate the probability density function of peak ground acceleration. Combining the probability density function of peak ground acceleration and the seismic fragility analysis, seismic risk assessment is performed. In this study, seismic fragility analysis is developed as a function of not the surface motion which the bridge actually suffers, but the rock outcrop motion which the aseismic design code is defined on, so that further analysis for the seismic hazard assessment may become available. Besides, the effects of the friction pot bearings and the friction pendulum bearings on the seismic fragility and risk analysis are examined. Lastly, three regions in Korea are considered and compared in the seismic risk assessment.

• 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.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1482-1488
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• 2009

최근 전 세계적인 기후변화로 인하여 홍수 해일 지진 등의 자연재해가 거대해지고 빈번하게 발생되고 있다. 이러한 점차 대형화되고 다양화되는 자연재해발생시 국민의 생명과 재산 피해를 최소화하기 위한 다양한 방안이 수립되고 있으며, 특히 풍수해에 대비하기 위한 방안으로써 비상대처계획(Emergency Action Plan, 이하 EAP)수립, 홍수위험지도 및 비상대피지도 등 재해지도 제작, 홍수재해관리시스템 개발 등이 이루어지고 있다. 특히 EAP는 이러한 점차 대형화되고 다양화되는 자연재해에 대비하기 위한 방안으로써, 재해 발생시 국민의 생명과 재산 피해를 최소화하기 위해 시설물 지역의 관리주체 및 유관기관이 발생 가능한 비상상황을 미리 예측하고 대응조치를 신속하고 효율적으로 집행할 수 있도록 구성되어 있으며, 이를 시스템화 한 것이 비상대처시스템(Emergency Action System, 이하 EAS)이라 할 수 있다. 현재 우리나라를 비롯하여 미국, 유럽, 일본 등 선진국을 중심으로 댐 저수지 붕괴에 대비한 EAP 수립을 의무화하고 그 대상 범위를 확장하는 단계에 있으며, 홍수위험지도 및 비상대피지도 제작 등에 있어서 일부 선진국의 경우 다양한 시나리오와 시민의 복합적인 요구를 반영하는 시도를 진행 중에 있다. 또한 일부 선진국의 경우 비상대처계획을 반영한 홍수재해통합관리시스템 구축이 진행중에 있으며, 일본의 경우 첨단기술의 접목을 통해 시민의 대피 시뮬레이션 모델을 개발하는 단계에 이르고 있다. 따라서 본 연구에서는 풍수해에 대비해 수립된 국내 외 EAP, 재해관련 지도, 홍수재해관리시스템 등에 대한 사례조사를 통하여 통합적인 비상대처 및 관리가 가능한 표준화된 EAS 모델의 정립 방향을 모색하고자 한다.

• Korean Journal of Remote Sensing
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• v.35 no.2
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• pp.217-228
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• 2019

In this study, a seismic vulnerability map of Gyeongju city, where the 9.12 Gyeongju earthquake occurred, was produced and evaluated using analytic hierarchy process(AHP) and geographic information system (GIS). Geotechnical, physical, social, structural, and capacity factors were selected as the main indicators and 18 sub-indicators to construct a spatial database. Weights derived using the AHP were applied to the 18 sub-indicators, which generated a vulnerability map of the five main indicators. After weighting the five generated maps, we created seismic vulnerability maps by overlaying each of the five maps. The seismic vulnerability map was classified into five zones, i.e., very high, high, moderate, low, and safe. For seismic vulnerability, the results indicated that 3% of Gyeongju area is characterized as having very high vulnerability, while 19% was characterized as safe. Based on district standards, Jungbu-dong, Hwangoh-dong, Hwangseong-dong, Seonggeon-dong, and Dongcheon-dong were high-risk areas, and Bodeok-dong, Gangdong-myeon, Yangbuk-myeon, Yangnam-myeon, and Oedong-eup were characterized as safe areas. The seismic vulnerability map produced in this study could possibly be used to minimize damage caused by earthquakes and could be used as a reference when establishing policies.

• Journal of Digital Contents Society
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• v.19 no.5
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• pp.899-906
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• 2018

In the entire process of disaster management, it is very significant to construct related information as well as perform quantitative assessment of damage losses with respect to minimizing the effect of disasters. Many countries have paid much attention not only to studying risk assessment methodologies including constructing inventories, hazard mapping, vulnerability assessment and direct/indirect damage loss estimation, but also to developing risk analysis tools investigated in this paper. We conducted comparison studies of representative earthquake damage risk analysis tools, and the result of this study is able to provide useful information to decision makers and researchers who can contribute to development of effective disaster management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1C
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• pp.65-76
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• 2010

Recent earthquake events revealed that severe seismic damages were concentrated mostly at sites composed of soil sediments rather than firm rock. This indicates that the site effects inducing the amplification of earthquake ground motion are associated mainly with the spatial distribution and dynamic properties of the soils overlying bedrock. In this study, an integrated GIS-based information system for geotechnical data was constructed to establish a regional counterplan against ground motions at a representative metropolitan area, Seoul, in Korea. To implement the GIS-based geotechnical information system for the Seoul area, existing geotechnical investigation data were collected in and around the study area and additionally a walkover site survey was carried out to acquire surface geo-knowledge data. For practical application of the geotechnical information system used to estimate the site effects at the area of interest, seismic zoning maps of geotechnical earthquake engineering parameters, such as the depth to bedrock and the site period, were created and presented as regional synthetic strategy for earthquake-induced hazards prediction. In addition, seismic zonation of site classification was also performed to determine the site amplification coefficients for seismic design at any site and administrative sub-unit in the Seoul area. Based on the case study on seismic zonations for Seoul, it was verified that the GIS-based geotechnical information system was very useful for the regional prediction of seismic hazards and also the decision support for seismic hazard mitigation particularly at the metropolitan area.

• Journal of the Korean Geotechnical Society
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• v.25 no.1
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• pp.5-19
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• 2009

Most of earthquake-induced geotechnical hazards have been caused by the site effects relating to the amplification of ground motion, which is strongly influenced by the local geologic conditions such as soil thickness or bedrock depth and soil stiffness. In this study, an integrated GIS-based information system for geotechnical data, called geotechnical information system (GTIS), was constructed to establish a regional counterplan against earthquake-induced hazards at an urban area of Daejeon, which is represented as a hub of research and development in Korea. To build the GTIS for the area concerned, pre-existing geotechnical data collections were performed across the extended area including the study area and site visits were additionally carried out to acquire surface geo-knowledge data. For practical application of the GTIS used to estimate the site effects at the area concerned, seismic zoning map of the site period was created and presented as regional synthetic strategy for earthquake-induced hazards prediction. In addition, seismic zonation for site classification according to the spatial distribution of the site period was also performed to determine the site amplification coefficients for seismic design and seismic performance evaluation at any site in the study area. Based on this case study on seismic zonations in Daejeon, it was verified that the GIS-based GTIS was very useful for the regional prediction of seismic hazards and also the decision support for seismic hazard mitigation.

• Journal of the Korean GEO-environmental Society
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• v.20 no.5
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• pp.5-12
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• 2019

On November 15, 2017, a unpredictable liquefaction damage was occurred at the $M_L=5.4$ Pohang earthquake and after, many researches have been conducted in Korea. In Korea, where there were no cases of earthquake damage, it has been extremely neglectable in preparing earthquake risk maps and building earthquake systems that corresponded to prevention and preparation. Since it is almost impossible to observe signs and symptoms of drought, floods, and typhoons in advance, it is very effective to predict the impacts and magnitudes of seismic events. In this study, 14,040 borehole data were collected in the metropolitan area and liquefaction evaluation was performed using the amplification factor. Based on this data, liquefaction hazard maps were prepared for ground accelerations of 0.06 g, 0.14 g, 0.22 g, and 0.30 g, including 200years return period to 4,800years return period. Also, the correlation analysis between the earthquake acceleration and LPI was carried out to draw a real-time predictable liquefaction hazard map. As a result, 707 correlation equations in every cells in GIS map were proposed. Finally, the simulation for liquefaction risk mapping against artificial earthquake was performed in the metropolitan area using the proposed correlation equations.

• The Journal of the Petrological Society of Korea
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• v.25 no.4
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• pp.325-334
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• 2016

Both 1900 years of historic literature and recent instrumental seismic records indicate the Korean Peninsula has repeatedly experienced small and large earthquakes. This study has used historical and instrumental records of Korea to investigate the characteristics of earthquakes in the peninsula. Results of GIS spatial analyses indicate Pyongyang, the capital of North Korea, is more vulnerable to the earthquake hazard than that of other regions in the Korean Peninsula. It is also noted that Pyongyang is exposed to high risks of other natural and social disasters because of the high population density and concentrated infra structures. Scenario shake map drawn up assuming a magnitude 6.7 earthquake, which was experienced in A.D. 502 in the area, indicates that 51.1% of the city are exposed to PGA 0.24 g or higher. Recent statistics by the Statistics Korea also indicates the North Korea is far more vulnerable to disasters than those in the South Korea. Results of the preliminary study provide essential information for comprehensive understanding of earthquake hazard estimation in Korea including the North Korea.

• Journal of Korean Society of Disaster and Security
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• v.12 no.1
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• pp.45-56
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• 2019

In this study, the seismic risk has been evaluated by setting the bedrock acceleration to 0.154g which, was taking into consideration that the earthquake return period for the buried electric power tunnels in the metropolitan area to be 1,000 years. In this case, the risk assessment during the earthquake was carried out in three stages. In the first stage, the site classification was performed based on the site investigation data of the target area. Then, the LPI(Liquefaction Potential Index) was applied using the site amplification factor. After, candidates were selected using a hazard map. In the second stage, risk assessment analysis of seismic response are evaluated thoroughly after the recalculation of the LPI based on the site characteristics from the boring logs around the electric power area that are highly probable to be liquefied in the first stage. The third Stage visited the electric power tunnels that are highly probable of liquefaction in the second stage to compensate for the limitations based on the borehole data. At this time, the risk of liquefaction was finally evaluated based off of the reinforcement method used at the time of construction, the application of seismic design, and the condition of the site.