• Title/Summary/Keyword: 적정 설계

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National Highway's Design Criteria Based on Analysis of Functional Classification (일반국도의 수행 기능 분석에 의한 적정 설계기준 연구)

  • 강원의
    • Journal of Korean Society of Transportation
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    • v.19 no.1
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    • pp.53-61
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    • 2001
  • This study shows that a functional order relationship of national highways in rural areas, which provides the functional system as a principal and minor arterial highways, can be established by the use of statististics. As a result, the adequate functional design criteria of those highways are proposed on the basis of the traffic characteristics in those areas. According to those statistical studies, a function of national highways in the national road network is proved to form three categories broadly. Especially, the survey results based on the traffic characteristics on each road sections show that the initially constructed national highways can not provide an adequate functional role as the arterial highways in the studied areas. In order to operate the intended national highways functionally as the arterial highways, the functional design criteria of highways and the standard order of highway facilities based on the design traffic speed should be considered as an alternative.

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Problems of Applying Design for Safety and Adequacy of Risk Factor Derived at Design Phase (설계단계 설계 안전성 검토 적용의 문제점과 도출 위험요인의 적정성)

  • Kim, Jin-Dong;Kim, Gwang-Hee
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.6
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    • pp.549-555
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    • 2019
  • While efforts to reduce safety accidents in the construction industry have been made in a variety of ways, so far they have had minimal effectiveness. For this reason, since 2016 Design for Safety (DfS) has been implemented as an attempt to eliminate the root cause of safety accidents by introducing the consideration of safety at the design stage. The purpose of this study was to derive the adequacy and problems of Design for Safety and to contribute to reducing safety accidents by establishing this system correctly. A questionnaire survey of related engineers and analysis of the Design for Safety report showed that the awareness of Design for Safety among engineers was low, while some of the risk factors derived from the design for safety were less relevant to the design. As such, efforts should be made to reduce the risk factors in the actual design stage so that it can contribute more to the reduction of safety accidents.

Determining Ideal Distance between Consecutive Exit Ramps (고속도로 연결로상 연속 분류지점 간의 이격거리 검토)

  • Lee, Seongkwan Mark;Lee, Ki Young;Jang, Jung Hwa
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.1D
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    • pp.65-72
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    • 2011
  • When an expressway intersects another expressway, a unique connector needs to be designed between the two consecutive exit ramps. In such a case, it is important to design a connector such that there is enough distance for drivers to find their way safely. A current design manual in Korea prescribes the minimum length of the connector as 240 m. In this research, we have suggested a method for calculating the minimum length of a connector in order to check the feasibility of the currently prescribed length. For this purpose, we have attempted to determine the total perception-reaction time and lane-changing time required by a driver. For determining the driver's perception-reaction time, we have used the driver's decision time in addition to the conventional 2.5 s of perception-reaction time for stopping sight distances. We have considered both the design speed and the average travel speed for the calculation of the length. To evaluate the accuracy of the new method, we have chosen four sites on expressways for which relatively high accident rates were recorded. As a result, we could verify that the current limit (240 m) was sufficient for drivers to be able to change lanes in the given specific geometry. However, the prescribed limit should be revised in case the drivers' decision time is considered to be their perception-reaction time. All new approaches for calculating the ideal length of a connector have been carried out by taking into account the design speed as well as the average travel speed. Owing to the characteristics of the specific geometry for two consecutive exit ramps and the large difference between the design speed and the average travel speed in the objective areas, it is more realistic to use the proposed method by keeping the decision time equal to a driver's perception-reaction time, in order to determine the ideal distance that should be maintained between two consecutive exit ramps.

Assessment of Adequacy of Urban Water Supply (도시 상수도 공급량 산정의 적정성 평가)

  • Kim, Jang Jin;Chang, Hyung Joon;Lee, Ho Jin
    • Journal of Korean Society of Disaster and Security
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    • v.14 no.4
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    • pp.61-67
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    • 2021
  • In this study, the adequacy of water supply critical factors of urban design was examined. The supply of water supply is analyzed in various ways as the design progresses. Starting with basic data collection and analysis a supply and demand plan is established to calculate the amount of water supply and in this study the adequacy of population estimation and original unit calculation was evaluated. Among the second new cities where actual data can be secured Wirye New Town was selected as the study target area. Related data were analyzed to confirm the future population and the original unit and compared with the measured data. As of September 2020, the population of Wirye New Town was 93,977, showing the appropriateness of about 84% with a planned population of 110,990 confirming that the planned population and the actual population were almost similar. In the case of the original unit, it was calculated as 314 liters per person in Seoul and 320 liters per person in Seongnam at the time of design. As a result, it was found that there was some agreement in the population estimation while examining the supply in the planned city. In the case of Korea, there is a lot of interest in revitalizing the existing city, away from continuous development. Therefore it is judged that there is a need for further research on the adequacy of supply for the old city center.

Regional Frequency Analysis for Rainfall using L-Moment (L-모멘트법에 의한 강우의 지역빈도분석)

  • Koh, Deuk-Koo;Choo, Tai-Ho;Maeng, Seung-Jin;Trivedi, Chanda
    • The Journal of the Korea Contents Association
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    • v.8 no.3
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    • pp.252-263
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    • 2008
  • This study was conducted to derive the optimal regionalization of the precipitation data which can be classified on the basis of climatologically and geographically homogeneous regions all over the regions except Cheju and Ulreung islands in Korea. A total of 65 rain gauges were used to regional analysis of precipitation. Annual maximum series for the consecutive durations of 1, 3, 6, 12, 24, 36, 48 and 72hr were used for various statistical analyses. K-means clustering mettled is used to identify homogeneous regions all over the regions. Five homogeneous regions for the precipitation were classified by the K-means clustering. Using the L-moment ratios and Kolmogorov-Smirnov test, the underlying regional probability distribution was identified to be the generalized extreme value (GEV) distribution among applied distributions. The regional and at-site parameters of the generalized extreme value distribution were estimated by the linear combination of the probability weighted moments, L-moment. The regional and at-site analysis for the design rainfall were tested by Monte Carlo simulation. Relative root-mean-square error (RRMSE), relative bias (RBIAS) and relative reduction (RR) in RRMSE were computed and compared with those resulting from at-site Monte Carlo simulation. All show that the regional analysis procedure can substantially reduce the RRMSE, RBIAS and RR in RRMSE in the prediction of design rainfall. Consequently, optimal design rainfalls following the regions and consecutive durations were derived by the regional frequency analysis.