• Title/Summary/Keyword: Disaster-Risk Evaluation

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Stochastic value index for seismic risk management of existing lifelines

  • Koike, Takeshi;Imai, Toshio
    • Structural Engineering and Mechanics
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    • v.32 no.1
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    • pp.147-165
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    • 2009
  • This study proposes a certain measure or investment strategy for decision making associated with seismic retrofitting. This strategy reduces the risk of a large-scale malfunction such as water supply loss under seismic risks. The authors developed a stochastic value index that will be used in the overall evaluation of social benefit, income gain, life cycle costs and failure compensation associated with existing lifeline systems damaged by an earthquake during the remaining service period. Optimal seismic disaster prevention investment of deteriorated lifeline systems is discussed. Finally, the present study provides a performance-based design method for seismic retrofitting strategies of existing lifelines which are carried out using the target probabilities of value loss and structural failure.

Evaluation of the Probability of the Steel Beam to Collapse in Accordance with the Normal Distribution Load (철골보의 정규하중분포에 따른 파손확률 평가)

  • Song, Chang-Young
    • Journal of Korean Society of Disaster and Security
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    • v.7 no.1
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    • pp.43-50
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    • 2014
  • Based on the reliability theory, the risk assessment of steel beams is performed by the determination of failure probability. In the calculation, bending, shearing and combined (bending + shearing) modes are examined. The resistance and the loads on the beam are assumed to be normal distribution. To investigate the failure probability changes, total load applied at the mid span of beam is divided into 1 to 1 and 1 to 2 ratio and then these divided loads are placed on the trisected points on beam. The change of boundary conditions at beam ends are also included in the investigation. It shows that failure is governed by the combined mode for the present beams and the second order bound analysis of failure probability is not crucial. On the whole failure probability decreases with increasing end restraints at the beam ends with some exception.

Study on the Establishment of a Safety Allowance Level of Disastrous and Hazardous Facilities in Large Cities (대도시 위해.위험시설에 대한 안전도 수용기준 정립에 관한 연구)

  • 고재선;윤명오
    • Fire Science and Engineering
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    • v.15 no.1
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    • pp.84-92
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    • 2001
  • In today's world, rise in the establishment of social infrastructure resulting from population saturation in large cities has led to more extensive and frequent use of chemical materials on facilities. A result, unexpected and serious accidents, hazards, contingencies and disasters are more prevalent than ever. Such phenomenon calls for more devoted and concerted efforts towards finding ways to reduce the safety hazards that are seen to take place more often than before with the increase in the number of facilities that are prone to bring disaster and hazard coupled with the conventional safety problems that continue to exist even today. In developed countries, such challenge is addressed by various appropriate countermeasures drawn up by local professional committees on industrial facilities, whose members conduct offsite and onsite evaluation un the potential industrial disasters and its seriousness and provide their advice thereof. Against this backdrop, this study aims at identifying a comprehensive safety allowance level (safety acceptable level) when imposing limitation on the development of conventional or new facilities, for the fur pose of establishing a safety allowance level of disastrous and dangerous facilities in Korea. This is done by assessing and applying the level of danger each individual is exposed to in a randomly selected region (disastrous and dangerous areas in Seoul) based on probability of quantitative hazards, as well as simulation and calculation methods which include: i) social disaster evaluation method applying Quantified Risk Assessment of Health & Safety Executive of UK and Matrix of Risk of Evaluated Sources of Hazard; ii) Fault Tree or Event Tree Analysis and etc.

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Analysis of the technical status of multiunit risk assessment in nuclear power plants

  • Seong, Changkyung;Heo, Gyunyoung;Baek, Sejin;Yoon, Ji Woong;Kim, Man Cheol
    • Nuclear Engineering and Technology
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    • v.50 no.3
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    • pp.319-326
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    • 2018
  • Since the Fukushima Daiichi nuclear disaster, concern and worry about multiunit accidents have been increasing. Korea has a higher urgency to evaluate its site risk because its number of nuclear power plants (NPPs) and population density are higher than those in other countries. Since the 1980s, technical documents have been published on multiunit probabilistic safety assessment (PSA), but the Fukushima accident accelerated research on multiunit PSA. It is therefore necessary to summarize the present situation and draw implications for further research. This article reviews journal and conference papers on multiunit or site risk evaluation published between 2011 and 2016. The contents of the reviewed literature are classified as research status, initiators, and methodologies representing dependencies, and the insights and conclusions are consolidated. As of 2017, the regulatory authority and nuclear power utility have launched a full-scale project to assess multiunit risk in Korea. This article provides comprehensive reference materials on the necessary enabling technology for subsequent studies of multiunit or site risk assessment.

Analysis of Fire Scenarios and Evaluation of Risks that might Occur in Operation Stage of CAES Storage Cavern (CAES 저장 공동 운영단계에서 발생 가능한 리스크 평가 및 화재 시나리오 분석)

  • Yoon, Yong-Kyun;Ju, Eun-Hye;Seo, Saem-Mul;Choi, Byung-Hee
    • Tunnel and Underground Space
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    • v.25 no.1
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    • pp.107-114
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    • 2015
  • This study focuses on assessing risks which might occur in operation stage of CAES storage cavern and analyzing fire scenarios for the risk that have been assessed with highest risk level. Risks in operation stage were categorized into upper risk group and lower risk group. Components of upper risk group are technical risk, facility risk and natural disaster risk. Lower risk group is composed of 11 sub-risks. 20 experts were chosen to survey questionnaires. ANP model was applied to analyze the relative importance of 11 sub-risks. Results of risk analysis were compared with risk criterion to set risk priorities, and the highest risk was determined to be 'occurrence of the fire within the management opening'. Three fire scenarios were developed for the highest risk level and FDS (Fire dynamics Simulator) was used to analyze these scenarios. No. 3 scenario which air blows from tunnel into outside atmosphere represented that a rate of smoke spread was the fastest among three fire scenarios and a smoke descended most quickly below the limit line of breathing. Thus, No. 3 scenario turned out to be the most unfavorable condition when operating staffs were evacuated from access tunnel.

A comparative Study for dispersion model in evacuation plan by using MAS-based evacuation simulation (MAS 기반 피난시뮬레이션을 이용한 분산대피 비교 연구)

  • Jang, Jae-Soon;Rie, Dong-Ho
    • Journal of the Korean Society of Safety
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    • v.29 no.1
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    • pp.59-63
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    • 2014
  • Smoke is one of the most critical factor when escaping from the fire since it reduces visibility and interrupts finding emergency exit lights. Therefore, it is recommended that an evacuation simulation program should incorporate the smoke factor. In addition, it is suggested that the program should include not only the unilateral damage by the smoke but also the detour evacuation by risk communication. In this study, MAS (Multi Agent System)-based simulation program which incorporates the reduced walking speed by smoke and adopts the dispersion evacuation logic during escaping from the fire. To make comparison, a commercial evacuation program, Pathfinder was used. It was found that the simulation results of MAS (Multi Agent System)-based program is better than Pathfinder in terms of safe evacuation. It means that evacuation simulation need a additional evaluation categories that include not only quick evacuation time but also safe evacuee number.

A Study on the Development of Evaluation Methods for Fire Risk Analysis of High-rise Building ((초)고층 건축물의 화재위험성 평가기법 위한 통계적 예측에 관한 연구)

  • Kwon, Young-Jin;Kim, Dong-Eun
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2009.04a
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    • pp.270-275
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    • 2009
  • 최근 소방법의 경우 초고층구조물을 대상으로 한 성능설계 및 화재영향평가등을 실시할 예정으로 있으며 특히 화재위험성평가등에 대한 대책이 요구되고 있으나 이에 대한 데이터가 부족하며 그 방법론 또한 구축되어 있지못한 상황이다. 따라서 본보는 전보에 이어 화재 위험성평가를 위한 방법론에 대한 일환으로서 위험성예측에 사용하는 화재발생의 상위에 의한 화재규모와 rmm 발생율을 각용도별로 기존의 화재에이터 및 가연물조사결과등으로부터 통계적으로 추정하는 방법에 대하여 검토한 것이다.

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Development of Risk Assessment Index in Special Management Target Facilities According to the Fire Occurrence Factors (화재발생 요인에 따른 특정관리대상시설등의 위험도 평가 지수의 분석 및 개발)

  • Park, Mi Yun;Park, Jong Bok;Park, Jae Hak
    • Journal of Korean Society of Disaster and Security
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    • v.5 no.2
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    • pp.61-70
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    • 2012
  • The range of special management target facilities is seperated by the building sector and the field of civil engineering. In the present study, the risk analysis was performed, related to fire occurred for the last five years, in the field of residential and non-residential facilities in buildings. Most of fire incidents occurred in residential and non-residential facilities was the cause of the electrical, and the resulting casualties were also very high. Therefore, based on the results, the risk evaluation index was developed, identifying the causes of fire occur and doing the fire vulnerability analysis for each facility. The result of this study can be utilized safety management to these facilities for the future, especially, inducing a more specialized and intensive safety management.

Evaluation of Steep Slopes Adjacent to Multi-use Facilities in National Parks using GIS (GIS를 활용한 국립공원 다중이용시설 인접 급경사지 평가)

  • Lee, Dong Hyeok;Jun, Kye Won;Jung, Min Jin;Park, Jun Hyo
    • Journal of Korean Society of Disaster and Security
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    • v.14 no.4
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    • pp.29-36
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    • 2021
  • Recently, due to climate change, the slope is increasing, and the risk of steep slope disasters such as the occurrence of slope collapse in the east coast and Busan region in 2019 and the Gokseong landslide in 2020 is increasing. Particularly, most national parks are made up of mountainous areas, and the risk of disasters on steep slopes is increasing. As the ground of the national park is aging and the weathering and jointing of the bedrock are accelerating due to climate change, the slope collapse and rockfall are increasing, and the annual number of visitors is increasing, it is necessary to manage steep slopes adjacent to multi-use facilities with many users. In this study, dangerous steep slopes that affect multi-use facilities in national parks were analyzed using GIS and verified through field surveys. As a process for extracting steep slopes adjacent to multi-use facilities in national parks, the slope was made in DEM and slopes of 34 degrees or higher were extracted. The difference between the maximum and minimum heights of the extracted slopes was used to confirm that the slopes met the standard for steep slopes, and the analysis of the slope direction was used to confirm whether it had an effect on the multi-use facilities. After that, precision aerial images and field photos were analyzed to finally identify risks at 4 sites, and field surveys were conducted. As a result of the field survey, all 4 sites were found to be steep slopes, 3 were graded D and 1 was graded C, so it was confirmed that management was required as a risk of collapse. All steep slopes extracted through GIS were found to be dangerous, so it is judged that the extraction of steep slopes through GIS would be appropriate.

Evaluation of Drought Risk in Gyeongsang-do Using EDI (EDI를 활용한 경상도 지역의 가뭄위험도 평가)

  • Park, Jong Yong;Yoo, Ji Young;Choi, Minha;Kim, Tae-Woong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.3B
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    • pp.243-252
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    • 2011
  • The change of rainfall pattern due to recent climate change increases the occurrence probability of drought in Korea. Unlike other natural disasters, a drought has long duration, extensive area subject to damage, and greater socioeconomic damage than other disasters. In order to evaluate drought severity, meteorological drought indices are mainly used in practice. This study presents a more realistic method to evaluate drought severity considering drought climate factors as well as socioeconomic factors which are vulnerable to disaster. To perform a spatial evaluation of drought risk in Gyeongsang-do, drought risk was defined and analyzed through the hazard index and the vulnerability index. The drought hazard index was spatially assessed using the drought index and GIS. The drought vulnerability index was also spatially assessed using the 5 socioeconomic factors. As a result, the drought risks were compared and used for evaluating regional drought risk considering regional characteristics of Gyeongsang-do.