• 한국해안해양공학회지
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• 제14권1호
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• pp.1-7
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• 2002

과거, 울진원전 부지의 지진해일에 대한 안전성 평가는 가상최대 지진규모와 그에 상응하는 단층 파라미터를 이용하여 수행되었으나. 최근 지진공백역 이론에 근거하여, 과거 평가 규모 이상의 지진발생 가능성이 지진학자들에 의하여 제기되고 있다. 본 연구에서는 선형·비선형천수방정식 기반의 유한차분법을 이용하여 지진해일 안전성을 재평가하였다. 먼저, '83년 지진해일을 모의하고 이를 동해안 임원항의 최고 범람 수위와 비교하였다. 다음으로 '83년, '93년 지진해일과 위험 단층으로 분류되고 있는 5개 지진공백역 단층에 대하여 울진원전부지 도수로에서의 수위 상승과 저하를 계산하여, 울진원전이 평가대상 단층으로 의한 지진해일 발생시에도 필요 냉각수의 취수가 가능함을 보였다.

• Nuclear Engineering and Technology
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• 제51권2호
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• pp.607-617
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• 2019

Global warming and climate change are increasing the intensity of typhoons and hurricanes and thus increasing the risk effects of typhoon and hurricane hazards on nuclear power plants (NPPs). To reflect these changes, a new NPP should be designed to endure design-basis hurricane wind speeds corresponding to an exceedance frequency of $10^{-7}/yr$. However, the short typhoon and hurricane observation records and uncertainties included in the inputs for an estimation cause significant uncertainty in the estimated wind speeds for return periods of longer than 100,000 years. A logic-tree framework is introduced to handle the epistemic uncertainty when estimating wind speeds. Three key parameters of a typhoon wind field model, i.e., the central pressure difference, pressure profile parameter, and radius to maximum wind, are used for constructing logic tree branches. The wind speeds of the simulated typhoons and the probable maximum wind speeds are estimated using Monte Carlo simulations, and wind hazard curves are derived as a function of the annual exceedance probability or return period. A logic tree decreases the epistemic uncertainty included in the wind intensity models and provides reasonably acceptable wind speeds.

• Earthquakes and Structures
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• 제26권2호
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• pp.87-96
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• 2024

This paper proposes a logistic multinomial regression approach to model the spatial cross-correlation of damage probabilities among different damage states in an expanded transportation network. Utilizing Bayesian theory and the multinomial logistic model, we analyze the damage states and probabilities of bridges while incorporating damage correlation. This correlation is considered both between bridges in a network and within each bridge's damage states. The correlation model of damage probabilities is applied to the seismic assessment of a portion of Tehran's transportation network, encompassing 26 bridges. Additionally, we introduce extra daily traffic time (EDTT) as an operational parameter of the transportation network and employ the shortest path algorithm to determine the path between two nodes. Our results demonstrate that incorporating the correlation of damage probabilities reduces the travel time of the selected network. The average decrease in travel time for the correlated case compared to the uncorrelated case, using two selected EDTT models, is 53% and 71%, respectively.

• Computers and Concrete
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• 제31권3호
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• pp.185-195
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• 2023

Antalya is located south part of minor Asia, one of the biggest cities in Türkiye. As a result of population growth and vast migration to Antalya, many parts of the city that were not suitable for construction due to its geological conditions have become urban areas, and most of these urban areas are full of poorly engineered buildings. Poor engineering has been combined with unplanned urbanization, that causes utter vulnerability to disasters in Antalya. When an earthquake-prone city, Antalya faces with an earthquake risk, fear arises in society. To overcome this problem, it has become necessary to investigate the building stock, expressed in hundreds of thousands, in a fast and reliable way and then perform an urban transformation to create the perception of structural safety. However, the excessive building stock, labor, and economic problems made the implementation stage challenging and revealed the necessity of finding alternative solutions in the field. The present study presents a novel approach for assessment and model based on a rapid visual inspection method to transform areas under earthquake risk in Türkiye. The approach aimed to rank the interventions for decision-making mechanisms by making comparisons in the scale hierarchy. In the present study, to investigate the proposed approach, over 26,000 buildings were examined in Antalya, which is the fifth largest city in Türkiye that has a population of over 2.5 Million. In the results of the study, the risk classification was defined in the framework of building, block, street, neighborhood, and district scales.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.261-268
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• 2006

This study represents results of fragility curve development for 3-span continuous bridge. To research the response of bridge under earthquake excitation, Monte Carlo simulation is performed to study nonlinear dynamic analysis. Because of limited number of real time histories from the Korean peninsula, a set of 150 synthetic time histories were generated. Fragility corves in this study are represented by lognormal distribution functions with two parameters and developed as a function of PGA. Five damage states were defined to express the condition of damage based on the actual experimental damage data of bridge column. As a result of this research, the value of damage probability corresponding to each damage state were determined. This approach may be used in constructing the fragility curves for all of bridge structure and, by extension, in constructing the seismic hazard map.

• 한국전산구조공학회논문집
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• 제37권3호
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• pp.205-216
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• 2024

최근 원자력 지진 PSA(Probabilistic Safety Assessment)를 토대로 산업시설물의 지진 PSA를 수행하는 연구가 진행되었다. 해당 연구는 원자력 발전소와 산업시설물의 차이를 파악하고, 최종적으로 운영정지를 목표로 하는 고장수목(Fault Tree)를 구축한 후 시각적 확률도구인 베이지안 네트워크(Bayesian Network, BN)으로 변환하였다. 본 연구는 선행연구를 기반으로 지진으로 유발된 구조손상으로 인해 발생 가능한 화재･폭발에 대해 PSA를 수행하고자 하였다. 이를 위해 화재･폭발을 사건수목(Event Tree)으로 표현하고, BN으로 변환하였다. 변환된 BN은 화재･폭발 모듈로서 선행연구에서 제시된 고장수목 기반 BN과 연계되어 최종적으로 지진 유발 화재･폭발 PSA를 수행할 수 있는 BN 기반 방법론이 개발되었다. 개발된 BN을 검증하기위해 수치예제로서 가상의 가스플랜트 Plot Plan을 생성하였고, 가스플랜트의 설비 종류가 구체적으로 반영된 대규모 BN을 구축하였다. 해당 BN을 이용하여 지진 규모에 따른 전체시스템의 운영정지 확률 및 하위시스템들의 고장확률 산정과 더불어 역으로 전체시스템이 운영 정지되었을 때 하위시스템들의 영향도 분석과 화재･폭발 가능성을 산정하여 다양한 의사결정을 수행할 수 있음을 제시함으로써 그 우수성을 확인하였다.

• Earthquakes and Structures
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• 제2권3호
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• pp.207-232
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• 2011

The development of reliable earthquake mitigation plans and seismic risk management procedures can only be based on the establishment of comprehensive earthquake hazard and loss scenarios. Two cities, Grevena (Greece) and D$\ddot{u}$zce (Turkey), were used as case studies in order to apply a comprehensive methodology for the vulnerability and loss assessment of lifelines. The methodology has the following distinctive phases: detailed inventory, identification of the typology of each component and system, evaluation of the probabilistic seismic hazard, geotechnical zonation, ground response analysis and estimation of the spatial distribution of seismic motion for different seismic scenarios, vulnerability analysis of the exposed elements at risk. Estimating adequate earthquake scenarios for different mean return periods, and selecting appropriate vulnerability functions, expected damages of the water and waste water systems in D$\ddot{u}$zce and of the roadway network and waste water system of Grevena are estimated and discussed; comparisons with observed earthquake damages are also made in the case of D$\ddot{u}$zce, proving the reliability and the efficiency of the proposed methodology. The results of the present study constitute a sound basis for the development of efficient loss scenarios for lifelines and infrastructure facilities in seismic prone areas. The first part of this paper, concerning the estimation of the seismic ground motions, has been utilized in the companion paper by Kappos et al. (2010) in the same journal.

• 한국방재학회 논문집
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• 제5권4호
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• pp.71-78
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• 2005

우리나라 도로교설계기준(2005)에서 규정하고 있는 내진설계의 기본개념은 인명피해를 최소화하고 설계지진은 구조물 수명동안 발생할 확률이 거의 없다는 것이다. 구조물 내진설계의 가장 상위개념이며 합리적인 내진대책은 인명피해를 최소화해야하며 경제성이 있어야 한다. 결과적으로 최우선의 목표를 만족시키기 위해서는 개별적인 구조물 중심이 아닌 도시 전체를 대상으로 한 거시적인 평가방안이 필요하다. 도시지역에 대한 피해상황은 기타지역과 다른 양상을 나타내며, 도시가 거대해질수록 구조물의 파손에 의한 손실보다는 오히려 이에 수반되는 부가적인 손실이 월등히 클 것이다. 그리고 거시적인 지진재해 평가방법은 인구와 구조물이 밀집되고, 정치 경제활동 등의 중심이 되는 오래된 도시일수록 효과가 탁월할 것이다. 본 연구는 지진재해위험을 합리적으로 예측할 수 있는 지진재해위험지수를 개발하고, 서울특별시를 6개 구역으로 분할하여 상대적인 지진재해위험을 평가하였다.

• 한국해안·해양공학회논문집
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• 제32권6호
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• pp.524-530
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• 2020

세굴에 의한 해상풍력터빈 지지구조물의 위험도 평가기법을 제안하였다. 제안방법은 세굴깊이별 발생확률과 세굴깊이에 따른 취약도를 이용한 위험도 평가방법이며 지진위험도 평가기법을 변형한 것이다. 세굴깊이의 확률분포는 유의파고, 유의 주기, 조류속 등 해양 환경조건을 고려하기 적합한 경험식을 이용해 산정했으며, 해상풍력터빈 지지구조물의 동적응답을 이용하여 세굴취약도 곡선을 산정하였다. 세굴깊이별 발생확률과 세굴에 의한 구조물의 세굴취약도 곡선을 결합하여 세굴위험도를 분석하였다.

• Earthquakes and Structures
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• 제8권3호
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• pp.573-589
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• 2015

In order to investigate the seismic behavior of highway bridges under near-fault earthquakes, a parametric study was conducted for different regular and irregular bridges. To this end, an existing regular viaduct Highway Bridge was used as a reference model and five irregular samples were generated by varying span length and pier height. The seismic response of the six highway bridges was evaluated by three dimensional non-linear response history analysis using an ensemble of far-fault and scenario-based near-fault records. In this regard, drift ratio, input and dissipated energy as well as damage index of bridges were compared under far- and near-fault motions. The results indicate that the drift ratio under near-fault motions, on the average, is 100% and 30% more than far-fault motions at DBE and MCE levels, respectively. The energy and damage index results demonstrate a dissipation of lower energy in piers and a significant increase of collapse risk, especially for irregular highway bridges, under near-fault ground motions.