• Earthquakes and Structures
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• v.19 no.5
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• pp.379-393
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• 2020

The purpose of this study is to first evaluate the seismic behavior of ageing arch bridges by using the Intensity Measure - based demand and DCFD format, which is referred to as the fragility-hazard format. Then, an investigation is performed for their seismic vulnerability. Analytical models are created for bridges concerning different features and these models are subjected to Incremental Dynamic Analysis (IDA) analysis using a set of 22 earthquake records. The hazard curve and results of IDA analysis are employed to evaluate the return period of exceeding the limit states in the IM-based probabilistic performance-based context. Subsequently, the fragility-hazard format is used to assess factored demand, factored capacity, and the ratio of the factored demand to the factored capacity of the models with respect to different performance objectives. Finally, the vulnerability curves are obtained for the investigated bridges in terms of the loss ratio. The results revealed that decreasing the span length of the unreinforced arch bridges leads to the increase in the return period of exceeding various limit states and factored capacity and decrease in the displacement demand, the probability of failure, the factored demand, as well as the factored demand to factored capacity ratios, loss ratio, and seismic vulnerability. Finally, it is derived that the probability of the need for rehabilitation increases by an increase in the span length of the models.

• Journal of Environmental Impact Assessment
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• v.18 no.1
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• pp.1-9
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• 2009

Even though the center of Cheongju city needs redevelopment because of a doughnut phenomenon, it has to be permitted within the environmental carrying capacity like a target water quality proposed on the Total maximum daily loads(TMDL) of Musim and Miho river watersheds. The aim of in this study is to identify the limit of redeveloping Cheongju downtown after analyzing its environmental carrying capacity using QUAL2E model. As a result of modeling various scenarios, the water quality of Musin river was shown that $BOD_5$ is 2.3mg/L which is the target water quality in the double of existing development plan of the Cheongju downtown. The water quality of Miho river was $BOD_5$ 3.97mg/L which is less than the target water quality of Miho B watershed in the same condition. Therefore, this means that the limit of redevelopment within the environmental carrying capacity of cheongju downtown was estimated to be the double of existing development plan.

• Nuclear Engineering and Technology
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• v.47 no.7
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• pp.884-894
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• 2015

Background: Fibers in concrete resist the growth of cracks and enhance the postcracking behavior of structures. The addition of fibers into a conventional reinforced concrete can improve the structural and functional performance of safety-related concrete structures in nuclear power plants. Methods: The influence of fibers on the ultimate internal pressure capacity of a prestressed concrete containment vessel (PCCV) was investigated through a comparison of the ultimate pressure capacities between conventional and fiber-reinforced PCCVs. Steel and polyamide fibers were used. The tension behaviors of conventional concrete and fiber-reinforced concrete specimens were investigated through uniaxial tension tests and their tension-stiffening models were obtained. Results: For a PCCV reinforced with 1% volume hooked-end steel fiber, the ultimate pressure capacity increased by approximately 12% in comparison with that for a conventional PCCV. For a PCCV reinforced with 1.5% volume polyamide fiber, an increase of approximately 3% was estimated for the ultimate pressure capacity. Conclusion: The ultimate pressure capacity can be greatly improved by introducing steel and polyamide fibers in a conventional reinforced concrete. Steel fibers are more effective at enhancing the containment performance of a PCCV than polyamide fibers. The fiber reinforcementwas shown to bemore effective at a high pressure loading and a lowprestress level.

• Journal of Korea Planning Association
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• v.53 no.7
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• pp.87-107
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• 2018

With more than 10 million inhabitants, in particular, Seoul, the capital of Korea, has already experienced a number of severe heat wave. To alleviate the potential impacts of heat wave and the vulnerability to heat wave, policy-makers have generally considered the option of heat wave strategies containing adaptation elements. From the perspective of sustainable planning for adaptation to heat wave, the objective of this study is to identify the elements of vulnerability and assess heat wave-vulnerability at the dong level. This study also performs an exploratory investigation of the spatial pattern of vulnerable areas in Seoul to heat wave by applying exploratory spatial data analysis. Then this study attempts to select areas with the relatively highest and lowest level of adaptive capacity to heat wave based on an framework of climate change vulnerability assessment. In our analysis, the adaptive capacity is the relatively highest for Seongsan-2-dong in Mapo and the relatively lowest for Changsin-3-dong in Jongno. This study sheds additional light on the spatial patterns of heat wave-vulnerability and the relationship between adaptive capacity and heat wave.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.3
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• pp.185-191
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• 2018

Post-earthquake risk assessment technique in Korea is developed in 2013 by National Disaster Management Research Institute, at the same time, related manual and standard regulation is distributed to every local government by National Emergency Management Agency. The objectives of this research are to investigate and evaluate the post-earthquake risk assessment of 9.12 Earthquake (M5.8, Gyeongju City, 2016) and 11.15 Earthquake (M5.4, Pohang City, 2017). To suggest and improve the assessment process of post-earthquake risk, first post-earthquake risk assessment method of advanced foreign countries including US, New Zealand and Japan are compared, and post-earthquake evaluation activities in 9.12 Earthquake and 11.15 Earthquake are analyzed. From the results, it is needed to expand the adapted building and structure types and strengthen the earthquake disaster response capacity of local government.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.4
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• pp.103-118
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• 2008

University campuses, in Korea, experienced expansion during the 1970's and exceeded its capacity in the 1980's. On the other hand, universities needed to deal with increasing capacity and expansion of its facilities. This study is carried out in three steps : developing the factors of environmental friendly assessment, designing an assessment table based on specific categories, and applying the categories to the campus of Seoul National University. The assessment factors and assessment table were designed through a survey of experts in landscaping, architecture, and urban planning. The elements of major categories were classified as follows; 1) Management of land and accessibility, 2) Pollution and waste matter, 3) Energy, 4) Natural resources, 5) Operation, maintenance and management of environmental friendly campus. And, this study classified five major categories into twenty subcategories on the evaluation of the environmental friendly campus. The twenty subcategories include various fields such as architecture, landscape architecture, environment, urban design, and social sciences etc., profound studies at this line should make more precise assesment guidelines.

• Journal of Environmental Impact Assessment
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• v.20 no.3
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• pp.411-424
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• 2011

Over the past three decades, Korea has undertaken a series of reforms to improve development policy, plans and programs, including measures to mainstream the environment across all major sectors. Despite of these efforts, there has been still the lack of capacity to fully assess the environmental impacts as well as sustainable implications of development projects and strategies. At the level of regional and sectoral development plans, the development of strategic environmental assessment SEA systems continues to remain at a relatively early stage in the region with fewer examples of fully operational processes or effective practice. This study shows a further information to our understanding of the EIA and SEA systems and their implementation in Korea. It affords a number of insights into strengths and weaknesses of the current action in different countries, and identifies an agenda of needs and options for capacity building for implementing the EIA enactment.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.5
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• pp.341-351
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• 2019

The purpose of this study was to evaluate vulnerability of drought in small island areas. Vulnerability assessment factors of drought were selected by applying the factor analysis. Ninety Eup/Myon areas in small island were evaluated to vulnerability of drought by entropy method adapting objective weights. Vulnerability consisted of climate exposure, sensitivity, and adaptive capacity. A total of 22 indicators were used to evaluate and analyze vulnerability of drought in small island areas. The results of entropy method showed that winter rainfall, no rainfall days, agricultural population rate, cultivation area rate, water supply rate and groundwater capacity have a significant impact on drought assessment. The overall assessment of vulnerability indicated that Seodo-myeon Ganghwa-gun, Seolcheon-myeon Namhae-gun and Samsan-myeon Ganghwa-gun were the most vulnerable to drought. Especially Ganghwa-gun should be considered policy priority to establish drought measures in the future, because it has a high vulnerability of drought.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.3
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• pp.35-51
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• 2015

The purpose of this study is to improve the previous groundwater contamination vulnerability assessment method, apply it to the study area, and select priority areas for groundwater management based on the quantitative analysis of groundwater contamination vulnerability. For this purpose, first, the previous 'potential contamination' based on groundwater contamination vulnerability assessment method was upgraded to the methodology considering 'adaptation capacity' which reduced contamination. Second, the weight of groundwater contamination vulnerability assessment factors was calculated based on the analytical hierarchy process(AHP) and the result of survey targeting groundwater experts. Third, Gyeonggi-do was selected as the study area and the improved methodology and weight were implemented with GIS and actual groundwater contamination vulnerability assessment was carried out. Fourth, the priority area for groundwater contamination management was selected based on the quantitative groundwater contamination vulnerability assessment diagram. The improved detailed groundwater contamination vulnerability assessment factors in this study were a total of 15 factors, and 15 factors were analyzed as new and improved weight with higher 'adaptation capacity' than the assessment factor corresponding to the previous 'potential contamination' in the weight calculation result using AHP. Also, the result of groundwater contamination vulnerability assessment in Gyeonggi Province using GIS showed that Goyang and Gwangmyeong which were adjacent to Seoul had a high groundwater contamination vulnerability and Pocheon and Yangpyeong County had a relatively low groundwater contamination vulnerability. In this study, the previous groundwater contamination vulnerability assessment was improved and applied to study areas actually. The result of this study can be utilized both directly and indirectly for the groundwater management master plan at national and local government level in the future.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1077-1092
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• 2007

The structural analysis model for estimate of load carrying capacity of railway bridge on service line is important to determine safety of bridges in service, we need to take response of bridge exactly, applying analysis model similar to the real railway bridge most. Track structure which is to distribute loads and decrease vibrations occurred from running train is constructed on the railway bridges. And it is important factor which should be considered to understand exact dynamic and static responses of bridge. But track structure is currently classified as a none structural members in the structural analysis model for estimating load carrying capacity of railway bridge and not considered in analysis model. That's the reason it is difficult to understand exact behavior of bridges. Therefore, the major objective of this study is to develop an analytical track-bridge model which is similar to real railway bridges considering track structure for safety assessment of railway bridge on service line to be effectively done.