• Title/Summary/Keyword: Maintenance and Repair

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Evaluation of Sleeper Supporting Condition for Railway Ballasted Track using Modal Test Technique (모달시험기법을 이용한 자갈궤도의 침목지지조건평가)

  • Jung-Youl Choi;Tae-Jung Yoon;Jee-Seung Chung
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.4
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    • pp.537-542
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    • 2023
  • Recently, deformation of operating railway structures has occurred due to adjacent excavation works such as new structures and utility tunnel expansion concentrated around downtown areas. However, most of them are focused on structural review, repair and reinforcement of structures. A review of the Track is insufficient. In particular, in the case of the gravel track on the earthwork subgrade, the subgrade and the ballast are not solidified. A slight level of deformation can cause ballast relaxation. Sleeper support conditions may lead to unstable conditions. Sufficient safety must be ensured. In addition, it is a track type with a high risk of train derailment due to unstable support conditions. In this study, the correlation between the deformation characteristics of gravel tracks and track support performance according to subgrade deformation is experimentally and analytically verified. In addition, an evaluation technique that can evaluate the condition of the gravel track and the track support stiffness is presented.

A Case Study of Estimating Units of Deconstruction Waste by Each Parts for the Apartment (공동주택의 분별해체를 위한 부위별 원단위 산정사례연구)

  • Kim, Chang Hak;Lee, Kyoung Hee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.1D
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    • pp.73-81
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    • 2008
  • Hereafter, the domestic housing industry has to give consequence to the redevelopment and rebuilding of existing housings rather than the supply by developing a new building site, and now those tendencies are rapidly spreading out. Also, because apartment buildings occupies 50% over of the existing housing, its maintenance, repair, remodeling and reconstruction got to be necessary area for the slumming prevention of a residential area and the disaster prevention occurred by durability lowering of the building. Accordingly, C&D waste is rising largely by reason of demolition works in city is increasing. The right management of C&D waste is being one of very important things, but little research has been conducted to estimate correctly C&D waste. In this study is to suggest standard units of C&D waste which can estimate demolition quantity of apartment. This units can estimate easily and correctly C&D waste in demolition works, also can possible use very important material to carry out policy of national waste management.

A Study on the Design & Construction Method of Traditional Landscape Space through the 『Imwongyeongjeji』 「Seomyongji」 and the 'Standard Specification for Repairing Cultural Heritages' (『임원경제지』 「섬용지」와 문화재수리 표준시방서를 통해 본 전통조경공간 설계 시공방법)

  • Lee, Jung-Han
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.37 no.4
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    • pp.1-10
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    • 2019
  • The purpose of this study is to examine the design & construction methods of the traditional landscape space of the past and the repair and maintenance of cultural heritages to maintain it today. To this end, the method of narrative description, process extraction and construction related to traditional landscaping were compared to each other based on the 『Imwongyeongjeji』 「Seomyongji」 and 'Standard Specification for Repairing Cultural Heritages'. The results are as follows; First, to analyze at the description methods of the 『Imwongyeongjeji』 「Seomyongji」 and 'Standard Specification for Repairing Cultural Heritages' and related processes in the field of traditional landscaping. 『Imwongyeongjeji』 「Seomyongji」 was an encyclopedia of the overall construction method of the living space, describing the location, effect, and advantages and disadvantages of each component and presenting quantitative figures to institutionalize the construction of traditional landscaping spaces. 'Standard Specification for Repairing Cultural Heritages' presented the entire process of repairing cultural heritages, and it is becoming a kind of guide for reference at the site. Among them, foundation construction, roof construction, landscape construction, and fence construction were drawn as items that could be applied to traditional landscaping areas. Second, the traditional landscape space construction method was divided into the processes of foundation construction, roof construction, landscaping construction, and fence construction. Foundation construction is a way of repeating the process of land-tramping. During the construction of the roof, the tile-roofed building was built on top of the rafters and roofed with tiles. And thatched roof was made to a number of rice straws bundles to cover the roof one after the other. Instead of tiles, the stone roof was made of thin and wide stones, and the wooden boards were used for the single roof and the bark roof were constructed with many layers of dried corrugations. Landscape construction mainly consists of the Paving technique through tramping rubble and the construction of terraced flower by planting stone, plants, and shrubs on the top. According to the building materials, the wall construction was derived from the earth-stacked earthen wall, stone walls using stone and clay, marble walls made of tile patterns, and the construction of a board wall using a wood board as a wall. Third, comparing the construction methods of the 『Imwongyeongjeji』 「Seomyongji」 and 'Standard Specification for Repairing Cultural Heritages', 『Imwongyeongjeji』 「Seomyongji」 focuses on standardizing the construction methods to create a new traditional space. There is a difference in the setting of the scope of the 『Imwongyeongjeji』 「Seomyongji」 and the construction because 'Standard Specification for Repairing Cultural Heritages' provides the overall construction procedure considering the diversity of the cultural heritages. In addition, the traditional landscape space used to be a residential space in the past, but today, the maintenance process of the already established facilities as designated cultural heritages has been carried out, and construction methods have been added to create viewing conditions. In terms of the succession of traditional knowledge, some similar methods were found in the repair of cultural assets today, and some cases were also confirmed in the reconstruction of traditional technologies such as application of some materials or mix, separation of added facilities and introduction of efficient construction methods.

Reinforcing effects of carbon fiber sheet by compressive strength differences on the RC slabs (도로교 RC 상판의 압축강도 차이에 따른 탄소섬유시트 보강효과)

  • Won, Chan Ho;Abe, Tadashi;Ahn, Tae-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.26 no.1
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    • pp.23-27
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    • 2016
  • This study investigates the effect of carbon fiber sheet (CFS) and carbon fiber strand sheet (CFSS) on the fatigue resistance and compressive strength of RC slabs. The results of a comparison of the number of equivalent cycles between the CFS- and CFSS-reinforced RC slab test specimens obtained from a fatigue test indicate that the CFSS-reinforced RC slab has 1.2~1.3 times greater effect of reinforcement than the CFS-reinforced RC slab. This study also indicates that the fatigue resistance of the CFS- and CFSS-reinforced RC slabs is ensured when the compressive strength of concrete is not lower than the specified design strength prescribed in the Specifications for Highway Bridges but is not ensured when the compressive strength of concrete is lower than the specified design strength, although the effect of reinforcement is secured.

A Study on Algorithm for Materials Take-off Using Pothole Detection System (포트홀 감지 시스템을 이용한 보수재료량 산출 알고리즘 개발)

  • Kim, Kyungnam;Kim, Sung-Ho;Kim, Nakseok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.3
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    • pp.603-610
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    • 2017
  • Various type of pavement deterioration such as crack, bumpy, pothole is rapidly increasing according to the accelerated environmental changes like heavy rainfall, frequent snowing, difference temperature, etc. Accident related to pothole that cause fatal traffic accidents has been increased more than five times over the next five years starting from 2008. As direct or indirect damage by pothole which caused injuries and car damages increases every year, quicker and more efficient management measures are necessary. This study presents the algorithm for materials quantity take-off. The algorithm was suggested by correlation in pothole size and area. Suggested algorithm were confirmed the validity through the 15 field survey in capital area. According to the results of survey, usually the residual materials at which 5~7 kg was generated decreased to 1~2 kg. It showed that automatic pothole detection system is expected not only to reduce materials and resources, but also to contribute to quality improvements of pavement through more accurate material take-off from the situation of constructing rely on their own judgement.

A Case Study of RAM Analysis Using Field Data: Focusing on Korean Warship (야전운용제원을 활용한 RAM분석 사례: 해군함정을 중심으로)

  • Sohn, Jung-Mok;Chang, Chung-Moo;Won, You-Dong
    • The Journal of the Korea Contents Association
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    • v.12 no.12
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    • pp.395-412
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    • 2012
  • RAM analysis using field data is important and useful for acquisition and operation of weapon systems. But this kind of analysis didn't conducted due to the absence of weapon system's failure data in case of warship. This study suggest failure tracking process based on maintenance and repair parts consumption data and proves suggested method enables conducting RAM analysis. This method obtains validity through field operator's reviews. The results on 9 warships in this study significantly correspond with weapon system operator's experiences. Because the result of this study contains effects of various operational environments in field, it will useful for correction and verification on existing another weapon system's RAM estimates. If this kind of RAM data are sufficiently accumulated, it will be used to DB of korean unique RAM analysis.

Behavior on Vertical Stiffener Length of Steel Box Girder Support Diaphragm (강상자형 다이아프램의 수직보강재 길이에 따른 거동)

  • Kim, Jong Ryeol;Kim, Woo Jun;Jung, Kyoung Sup
    • Journal of Korean Society of Steel Construction
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    • v.15 no.5 s.66
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    • pp.489-497
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    • 2003
  • Bridge has to be long-spanned and of simple structure, considering the social environment. As a result of this trend in bridge construction, it is important for the sake of economical efficiency to improve the structural system and increase the life cycle of a bridge. To attain these goals in constructing a steel bridge, the detail analyses based on real structure must be performed. In the steel structure bridge, the parts that are a main focus of interest are the diaphragm and the vertical bracing of the steel box girder support. This study observed the behavior of the diaphragms on the bearings of a closed section steel box girder bridge support, as dead load was increased. Stress variation of the support diaphragms in a steel box girder was considered, and both experimental test and structural analyses were performed to verify the behavior of a composite steel box girder bridge under repair or maintenance.

Effect of DPBll Gene for the Transcriptional Induction by DNA Damage During Cell Cycle in Saccharomyces cerevisiae (출아효모의 세포주기동안 DNA 상해에 의한 발현 유도에 미치는 DPB11 유전자의 영향)

  • 선우양일;임선희;배호정;김중현;김은아;김승일;김수현;박정은;김재우
    • Korean Journal of Microbiology
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    • v.38 no.2
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    • pp.96-102
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    • 2002
  • The S-phase checkpoint mechanisms response to DNA damage or inhibition of DNA replication for maintenance of genetic stability in eukaryotic cells. These roles include cell cycle control arrest at S-phase and Iranscriptional induction of repair genes. To characterize the defects of dpbll mutant for both these responses, we examined the over-expression effect of DPBll gene, the sensitivity to HU, MMS, and the transcriptional pattern by DNA damage agent for RNRS mRNA. RNRS transcript is induced in response to a wide variety of agents that either damage D7A directly through chemical modification or induce stress by blocking DNA synthesis. As results, dpbll-1 cells are sensitive to DNA damage agents and the level of RNR3 mRNA is reduced approximately 40% than wild type cells. Moreover, we found the same results in dpb2-1 cells. Therefore, we propose that DPB2 and DPBll act as a sensor of replication that coordinates the transcriptional and cell cycle responses to replication blocks.

Crack Control of the Upside of Double Tee Slab and Inversed Tee Beam Joint (더블티 슬래브-역티형 보 접합부 상부의 균열억제를 위한 실험연구)

  • Nam, Sang-Uk;Song, Han-Beom;Yi, Waon-Ho;Yang, Won-Jik;Baik, Young-Soo;Tae, Kyung-Hoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.345-348
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    • 2008
  • Recently, demand is caused that new building environment of value added rising demand on the lines of becoming bigger, manhattanize of structure and becoming high standard of structure in a construction site and influx of advanced foreign nation technique. To satisfy these requirements for alternative, structures applied to the PSC, PC is increasing. Double Tee Slab is possible for long length structure and applied to the method of construction. When assembling Double Tee Slab produced by the factory in the field, becamed carry-out topping concrete in upper, but occurred crack to slab line. There is no structural problem to crack occurred in upper, waterproof in maintenance and repair of structure due to a conservative cause several problems.

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The measurement of the half period modulated pulse on earth for detection of a underground electric leakage point (지중선로 누전점 탐지를 위한 반주기 변조된 대지 펄스 측정)

  • Kim, Jae-Hyun;Jeon, Jeong-Chay;Yoo, Jae-Geun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.11
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    • pp.5123-5127
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    • 2011
  • Research and development for the technology, that is about maintenance and accidents prevention of underground power distribution line, are demanding. The precise detection of leakage point of underground power line is very important, because it is difficult to detect the exact location of a fault in underground power line and to repair faults. When earth electric potential is measured to detect underground electric leakage point after transmitting AC electric pulse wave to underground power line, it must be measured in a specific half period of AC pulse wave because the distribution of the electric earth potential varies with the polarity of the transmitted wave. In this paper we proposed the measurement of half period modulated earth potential as a method to detect a underground leakage point. And We compared the proposed method with other methods. Through experiments we verified that the proposed method can be implemented and operated properly.