• Title/Summary/Keyword: 시공시스템

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Analysis of re-bar manufacturing system in plant and its facilitate method (철근공사의 공장가공 현황분석과 활성화 방안)

  • Cho, Hun-Hee;Kang, Tai-Kyung;Park, Hyun-Yong;Yun, Seok-Heon;Hur, Young-Ki;Park, U-Yeol
    • Korean Journal of Construction Engineering and Management
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    • v.8 no.1 s.35
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    • pp.57-65
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    • 2007
  • Rebar work is a labor intensive operation, and with labor shortage and high-wage era, the cost is rising, so re-bar manufacturing system in plant is adapted. However there remains a lot of problems. Although manufacturing system in plant, which greatly effects the building's safety, endurance, and construction time, is an important phase in construction, it holds serious problem of quality and productivity deterioration due to its characteristic of intensive-labor and maintaining of old work methods resulting in poor management, and costs increase. Therefor in this study to investigate current situation and problems of rebar work in plant and to find methods of betterment, a survey was conducted to factory engineers in 18 companies.

Comparative Study on the Characteristics of Ground Vibrations Produced from Borehole Blast Tests Using Electronic and Electric Detonators (전자뇌관과 전기뇌관을 사용한 시추공 발파시험에서의 지반진동 특성에 관한 비교 연구)

  • Choi, Hyung-Bin;Won, Yeon-Ho
    • Explosives and Blasting
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    • v.28 no.2
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    • pp.37-49
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    • 2010
  • Ground vibration caused by blasting in the urban area close to structures can give some indirect damage to human body and may lead to structural damage to buildings. At the stage of design or when complaints were filed by residents, the test blasting in borehole, which is most practical for expressing simple vibration wave form quantitatively, is usually chosen for assessing the degree of damage to structures. In this paper, some lessons gained from the application of electronic detonator triggering system in borehole test blasting are presented. The difference in delay time of detonator when borehole is blasted by electronic detonator and electric detonator are discussed. The peak particle velocities measured at the structure embedded in the similar rock layer to main line of tunnel at test site and measured at the road surface just above the tunnel having different overburden layers were analysed to draw their relationship. By comparing the results with those appearing in some published literatures, the usefulness of the borehole test blasting and the importance of delay time of detonator are addressed.

Assessment of the Anchor Head System Embedded in the Ground Surface (지표면에 근입한 앵커두부처리 시스템의 적용성 평가)

  • Min, Kyoung-Nam;Bae, Woo-Seok;Ahn, Kwang-Kuk;Jeong, Ku-Sic
    • The Journal of Engineering Geology
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    • v.22 no.1
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    • pp.49-58
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    • 2012
  • Anchor heads a recommonly exposed to surface weathering processes that cause physical damage by vibration and external forces. This study presents a new method of anchor-head installation that uses near-surface embedding based on analyses of concrete block failure. ABAQUS 3D numerical modeling performed to compare this method with the standard technique and to analyze the distribution of displacement and the stress pattern. In addition, application of the method to a real-world case was tested by in-situ measurements. The results show a maximum vertical stress of 9.73 MPa and vertical displacement of 1.34 mm. Field tests indicated that displacement of a concrete block was 3 to 4 times greater than that of an embedded bearing plate.

Security Interpretation of the Restriction Boundary of Building for Antiquated Tunnel using 3 Dimensional Surveying (3차원 측량에 의한 노후 터널의 건축한계 확보 해석)

  • Bae Sang-Ho;Lee Hyung-Seok
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.3
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    • pp.251-259
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    • 2006
  • For the electrification of the existing railways, the security of the restriction boundary of building with mechanistic stability research on the antiquated tunnel must be accomplished essentially. If the tunnel don't secure its restriction boundary of building, the reconstruction based on improvement of tunnel alignment are generated and its surveying data are required. The precise surveying was conducted with the same coordinate system for three tunnels of Youngdong tramline, and the restriction boundary of building of the straight and curve section were analyzed effectively by acquiring the data of profile and cross section, profile rail-height, rail-grade, cross tunnel height, and restriction boundary of building. This study is presented for valuation data of the stability of the electrification design to construct and analyze restriction boundary of building, which compared with the drawing and its existing design using profile and cross section. After this, it is interoperable to increase the development of real-time monitoring system on the tunnel structures.

Development of Database System (GeoINFO) for the Investigation, Design and Construction of Underground Space (지하공간의 조사, 설계 및 시공을 위한 데이터베이스 GeoINFO의 개발)

  • 김재동;박연준;유지선;김동현
    • Tunnel and Underground Space
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    • v.10 no.4
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    • pp.506-515
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    • 2000
  • A lot of underground construction projects have been conducted by economical, social and military purposes in Korea for the last three decades. As a result, magnificent amount of data were obtained from geological site investigations, laboratory and field tests, design and field monitoring. But up to now, these valuable informations were neither systematically stored nor utilized efficiently resulting in a great loss of time and money. In this study, a database system named GeoINFO was developed using Microsoft Access 97 for management of informations which can be obtained from underground construction. The developed database system is especially designed to cover three major types of underground facilities-tunnels, underground storages and rock slopes and has multi-layered tree structures for data input. The system also has a unique indexing system for efficient data search using Visual Basic code.

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Rating and Lifetime Prediction of a Bridge with Maintenance (유지관리보수가 된 교량의 내하력평가 및 잔존수명 예측)

  • Seung-Ie Yang;Han-Jung Kim
    • Journal of the Korean Society of Safety
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    • v.18 no.1
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    • pp.108-115
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    • 2003
  • Bridges are rated at two levels by either Load Factor Design (LFD) or Allowable Stress Design (ASD). The lower level rating is called Inventory Rating and the upper level rating is called Operating Rating. To maintain bridges effectively, there is an urgent need to assess actual bridge loading carrying capacity and to predict their remaining life from a system reliability viewpoint. The lifetime functions are introduced and explained to predict the time-dependent failure probability. The bridge studied in this paper was built 30 years ago in rural area. For this bridge, the load test and rehabilitation were conducted. The time-dependent system failure probability is predicted with or without rehabilitation. As a case study, an optional rehabilitation is suggested, and fir this rehabilitation, load rating is computed and the time-dependent system failure probability is predicted. Based on rehabilitation costs and extended service lifes, the optimal rehabilitation is suggested.

Enhancing maintenance performance of tunnel drainage using vibration from polyvinylidene fluoride(PVDF) film (압전필름의 진동을 활용한 터널배수재 유지관리 성능 개선)

  • Xin, Zhen-Hua;Moon, Jun-Ho;Song, Young-Karb;Kim, Young-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.822-826
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    • 2015
  • This study investigated the possible use of vibration from polyvinylidene fluoride(PVDF) film to enhance the performance of the deteriorated tunnel drainage due to physical/chemical clogging of the fine particles through a series of laboratory experiments. The test program was consisted of two different experiments, fundamental investigation and drainage model test. In the fundamental investigation, flow of clay slurry mixed with 50% water (freshwater and brine) on PVDF film with various frequencies was examined. In the model tests, slurry clogging to the woven fiber attached to drainage pipe and its reduction by vibration was investigated. Results of the experiment show that vibration from PVDF film enhances the drain performance significantly. Based upon the investigation, it gives an essential data that are needed for a potential use of hybrid drainage system with PVDF.

Study on Local Buckling of District Heating Pipes Using Limit State Design (한계상태 설계법을 이용한 지역난방 열배관의 국부좌굴 연구)

  • Kim, Joo-Yong;Lee, Sang-Youn;Ko, Hyun-Il;Cho, Chong-Du
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.12
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    • pp.1829-1836
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    • 2010
  • The district heating system distributes the heat generated from a cogeneration plant to wider locations. In this process, the district heating pipe (DHP) is subjected to internal and external loadings. The internal loadings are generally caused by the operating conditions such as water temperature and internal pressure. Frictional interactions between the pipes and the soil contribute to the external loadings. Thus, investigation of the mechanisms of failure of DHPs will help to guarantee both mechanical stability and heating efficiency. In this study, we investigate the local buckling of DHPs using limit state design (LSD). Two methods are considered: the use of the limit state for the width-thickness ratio and the use of the limit state for the strain. The results are used to confirm that the DHP is stable under local buckling. Finally, we suggest a minimum preheating temperature for avoiding local buckling.

Evaluation of Flexural Behavior of a Modular Pier with Circular CFT (충전원형강관을 이용한 모듈러 교각의 휨 거동 평가)

  • Ma, Hyang Wook;Oh, Hyun Chul;Kim, Dong Wook;Kong, Davon;Shim, Chang Su
    • Journal of Korean Society of Steel Construction
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    • v.24 no.6
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    • pp.725-734
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    • 2012
  • A new modular pier system using concrete filled circular steel tubes was suggested to realize modular bridge substructures for accelerated bridge construction. Structural details and connection details were proposed by connection multiple concrete filled tubes (CFT) for standardized products of fabrication, delivery and erection. Static tests were performed for the modular pier with suggested details under lateral load conditions for weak and strong axes. Due to the eccentricity by the bracing system, the modular pier showed 5.23 times higher flexural stiffness and 6 times greater flexural strength from the test. It is proper for the rational design to evaluate stress and deformation by frame modeling of the modular CFT pier. Structural capacity of the pier can be obtained by adjusting the spacing of the CFT columns. Design recommendations were derived from the test.

An Analytical Study on the behavior of the Pier considering Soil Conditions (지반 조건을 고려한 잔교의 거동에 관한 해석적 연구)

  • Sin, Ha Myung;Yoon, Gi Yong;Park, Jong Sup
    • 한국방재학회:학술대회논문집
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    • 2011.02a
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    • pp.214-214
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    • 2011
  • 최근 국내 연안역에는 관광의 활성화 등의 목적으로 잔교가 많이 가설되고 있다. 그러나 잔교의 설계에 대한 규정이 없어 현재는 항만 및 어항설계기준을 준용하여 설계하고 있는 실정이며, 또한 지역적 특성을 반영하지 못하고 건설되어 과다한 단면을 사용하는 경우가 많고, 경제성이나 경관성을 갖추지 못한 경우가 많은 실정이다. 본 연구에서는 합리적인 잔교용 설계기준을 마련하기 위한 기초적인 연구로써 지반조건을 고려한 잔교의 거동특성을 분석하고자 하였다. 이를 위하여 해석모델을 개발하고, 다양한 해석조건에 대한 해석을 수행하여 그 특성을 정리하고자 하였다. 이를 통하여 잔교의 합리적인 구조시스템을 개발하고, 설계기준을 정리하는데 이바지 하고자 한다. 이 연구에서는 서해안의 연약지반을 고려하기 위해 지반스프링을 이용한 해석모델을 개발하고, 다양한 해석조건에 대한 해석을 수행하여 그 특성을 파악하고자 하였다. 조립식 잔교는 Capbeam, Wood Deck, ㄱ형강, Pile로 네 가지의 구성으로 이루어지고, 이 네 가지 요소의 재료는 강재로 사용하였으며, 하중에 대해서는 항만 및 어항설계기준을 준용하여 군중하중 $5kN/m^2$, 월파력 $20.1kN/m^2$을 사용하였고, 풍하중은 도로교 설계기준을 이용하여 산정한 $3.309kN/m^2$을 사용하였다. 재하하중 및 하중에 대한 최적단면에 대한 연구를 활용하여 본 연구에서는 지반조건의 영향, Capbeam과 Pile의 크기변화, 사항 등의 영향을 고려하였을 때 각 구성요소에서 발생하는 단면력의 변화와 축력, 접합부 모멘트 등의 외력과 내력을 정리하여 잔교의 거동특성을 파악하고자 하였다. 다양한 변수해석을 수행하기 위하여 지반조건을 고려한 2D 해석모델을 개발하였으며, 본 연구에서 고려한 군중하중, 풍하중, 월파력의 설계하중 중에서는 월파력이 지배적인 것을 알 수 있었다. Pier의 지름이 증가 하면 작용하는 월파력이 커지고 따라서 단면력이 증가하는 것을 알 수 있었다. 그러므로 합리적인 Pier의 크기 결정이 경제적이고 경관이 우수한 잔교 건설에 중요 요인임을 알 수 있다. 본 연구는 잔교의 설계기준 정립에 기초자료로 활용할 수 있을 것으로 판단되나, 보다 합리적인 잔교의 설계와 시공을 위해서는 지속적인 연구가 필요한 것으로 판단된다.

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