• Title/Summary/Keyword: 확률론적 평가

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A Study on the Probabilistic Analysis Method Considering Spatial Variability of Soil Properties (지반의 공간적 변동성을 고려한 확률론적 해석기법에 관한 연구)

  • Cho, Sung-Eun;Park, Hyung-Choon
    • Journal of the Korean Geotechnical Society
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    • v.24 no.8
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    • pp.111-123
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    • 2008
  • Geotechnical engineering problems are characterized by many sources of uncertainty. Some of these sources are connected to the uncertainties of soil properties involved in the analysis. In this paper, a numerical procedure for a probabilistic analysis that considers the spatial variability of soil properties is presented to study the response of spatially random soil. The approach integrates a commercial finite difference method and random field theory into the framework of a probabilistic analysis. Two-dimensional non-Gaussian random fields are generated based on a Karhunen-$Lo{\grave{e}}ve$ expansion in a fashion consistent with a specified marginal distribution function and an autocorrelation function. A Monte Carlo simulation is then used to determine the statistical response based on the random fields. A series of analyses were performed to study the effects of uncertainty due to the spatial heterogeneity on the settlement and bearing capacity of a rough strip footing. The simulations provide insight into the application of uncertainty treatment to the geotechnical problem and show the importance of the spatial variability of soil properties with regard to the outcome of a probabilistic assessment.

Optimum Service Life Management Based on Probabilistic Life-Cycle Cost-Benefit Analysis (확률론적 생애주기비용-이익분석 기반 수명관리 최적화 기법)

  • Kim, Sunyong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.4
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    • pp.19-25
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    • 2016
  • Engineering structures including civil infrastructures require a life-cycle cost and benefit during their service lives. The service life of a structure can be extended through appropriate inspection and maintenance actions. In general, this service life extension requires more life-cycle cost and cumulative benefit. For this reason, structure managers need to make a rational decision regarding the service life management considering both the cost and benefit simultaneously. In this paper, the probabilistic decision tool to determine the optimal service life based on cost-benefit analysis is presented. This decision tool requires an estimation of the time-dependent effective cost-benefit under uncertainty to formulate the optimization problem. The effective cost-benefit is expressed by the difference between the cumulative benefit and life-cycle cost of a deteriorating structure over time. The objective of the optimization problem is maximizing the effective cost-benefit, and the associated solutions are the optimal service life and maintenance interventions. The decision tool presented in this paper can be applied to any deteriorating engineering structure.

Probabilistic Safety Assessment of Offsite Power System Under Typhoon-induced High Wind (소외전력망의 태풍 동반 강풍 확률론적 안전성 평가)

  • Kim, Gungyu;Kwag, Shinyoung;Eem, Seunghyun;Jin, Seung-Seop
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.44 no.3
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    • pp.277-282
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    • 2024
  • Recently, the intensity and frequency of typhoons have been increasing due to climate change, and typhoons can cause a loss of offsite power (LOOP) at nuclear power plants (NPPs). Therefore, it is necessary to prepare for typhoon-induced high winds through the probabilistic safety assessment (PSA) of offsite power systems. However, research on PSA for offsite power system in NPPs under typhoon-induced high winds is still lacking. In this study, PSA was performed for offsite power systems subjected to typhoon-induced high winds at the Kori NPP site, which has experienced frequent damages to its offsite power system among NPP sites in Korea. In order to perform PSA for typhoon-induced high winds in offsite power systems, the typhoon hazard at Kori NPP site was derived using logic tree and Monte Carlo simulation. Utilizing the fragility of components constituting the power system, performed a fragility analysis of the power system. Lastly, the probability that offsite power system will not be able to supply power to the NPP was derived.

Evaluation of Liquefaction Potential for Soil Using Probabilistic Approaches (확률적 접근방법에 의한 지반의 액상화 가능성 평가)

  • Yi, Jin-Hak;Kwon, O-Soon;Park, Woo-Sun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5C
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    • pp.313-322
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    • 2006
  • Liquefaction of soil foundation is one of the major seismic damage types for infrastructures. In this paper, deterministic and probabilistic approaches for the evaluation of liquefaction potential are briefly summarized and the risk assessment method is newly proposed using seismic fragility and seismic hazard analyses. Currently the deterministic approach is widely used to evaluate the liquefaction potential in Korea. However, it is very difficult to handle a certain degree of uncertainties in the soil properties such as elastic modulus and resistant capacity by deterministic approach, and the probabilistic approaches are known as more promising. Two types of probabilistic approaches are introduced including (1) the reliability analysis (to obtain probability of failure) for a given design earthquake and (2) the seismic risk analysis of liquefaction for a specific soil for a given service life. The results from different methods show a similar trend, and the liquefaction potential can be more quantitatively evaluated using the new risk analysis method.