• Title/Summary/Keyword: 조립식

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Analytical Study on the Inelastic Behavior of Precast Segmental Prestressed Concrete Bridge Piers (조립식 프리스트레스트 콘크리트 교각의 비탄성거동에 관한 해석적 연구)

  • Kim, Tae-Hoon;Jin, Byeong-Moo;Kim, Young-Jin;Shin, Hyun-Mock
    • Journal of the Earthquake Engineering Society of Korea
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    • v.9 no.5 s.45
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    • pp.29-40
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    • 2005
  • The purpose of this study is to investigate the inelastic behavior of precast segmental prestressed concrete bridge piers. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. An unbonded tendon element based on the finite element method, that can represent the interaction between tendon and concrete of prestressed concrete member, is used. A joint element is newly developed to predict the inelastic behaviors of segmental joints. The proposed numerical method for the inelastic behavior of precast segmental prestressed concrete bridge piers is verified by comparison with reliable experimental results.

Analytical Study on Joints in Precast Segmental Prestressed Concrete Bridge Piers (조립식 프리스트레스트 콘크리트 교각의 접합부에 관한 해석적 연구)

  • Kim, Tae-Hoon;Jin, Byeong-Moo;Kim, Young-Jin;Shin, Hyun-Mock
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.1 s.53
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    • pp.79-87
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    • 2007
  • This paper presents an analysis procedures of Joints in precast segmental prestressed concrete bridge piers. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. An unbended tendon element based on the finite element method, that can represent the interaction between tendon and concrete of prestressed concrete member, is used. A joint element is newly developed to predict the inelastic behaviors of segmental joints. The proposed numerical method for joints in precast segmental prestressed concrete bridge piers is verified by comparison with reliable experimental results.

A Study on the Structural Stability of Prefabricated Strut for Ground Excavation Construction (지반굴착용 조립식 버팀보의 구조 안정성에 관한 연구)

  • Lee, Ki-Sun;Kim, Doo-Hwan;Song, Kwan-Kwon;Kim, Seong-Pil;Kim, Jeong-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.3
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    • pp.75-83
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    • 2018
  • In study, Structural stability was considered when applying the high strength strut method with improved general strut method. considered whether there is sufficient stiffness to so as not buckling to the maximum hypothetical earth pressure. also structure stability of the strut component was reviewed. The high strength strut method is a technique used in place of the general strut method. high strength prefabricated Strut method is a technique that has bolt holes drilled in the upper flange at regular intervals. As a result of the buckling analysis, it was considered that the safety factor increased by about 5 %. also Since the stress generated is below the allowable stress, it is judged that structural stability of the strut is ensured. In particular, the safety factor of axial compressive stress increases about 16 % with use of high strength steel when applying the high strength prefabricated strut method. the high strength strut method is construction method may shorten the construction period and there is no expense to purchase additional materials.

Analysis of Orthomosaic and DSM Generation Using an Assembled Small-sized Drone (조립식 소형 드론을 이용한 Orthomosaic 및 DSM 생성 연구)

  • Kim, Jong Chan;Kim, Byung-Guk
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.3
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    • pp.195-202
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    • 2017
  • Ortho images created by aerial photogrammetry have been used in large areas but they are uneconomical for small areas and continuous change observation. The drones have been developed for military purposes, and recently they are being used crop management and analysis, broadcast relay, meteorological observation and disaster investigation and so on. Also there were a lot of studies of expensive commercial drone. In this paper, lower price self-assembly drone usable for in small areas, Obtained images and produced Orthomosaic and DSM using mission planner which is a normal digital camera and open source program, and postprocessing was used Pix4d software. GCP errors are X-coordinate 3.4cm, Y-coordinate 2.4cm, Z-coordinate 4.2cm. It seems like the self-assembly drone can be used for various fields.

Precast Segmental PSC Bridge Columns with Precast Concrete Footings : II. Experiments and Analyses (조립식 기초부를 갖는 프리캐스트 세그먼트 PSC 교각 : II. 실험 및 해석)

  • Kim, Tae-Hoon;Kim, Young-Jin;Lee, Jae-Hoon;Shin, Hyun-Mock
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.4A
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    • pp.407-419
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    • 2009
  • The purpose of this study is to investigate the seismic behavior of precast segmental PSC bridge columns with precast concrete footings and to provide the details and reference data. Six precast segmental PSC bridge columns were tested under a constant axial load and a cyclically reversed horizontal load. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. A bonded or unbonded tendon element based on the finite element method, that can represent the interaction between tendon and concrete of prestressed concrete member, is used. A joint element is modified to predict the inelastic behaviors of segmental joints. This study documents the testing of precast segmental PSC bridge columns with precast concrete footings and presents conclusions based on the experimental and analytical findings.

Effects of Design Parameters on Structural Performance of Precast Piers with Bonded Prestressing Steels (부착 긴장재를 가진 조립식 교각 설계변수의 구조성능에 미치는 영향)

  • Shim, Chang-Su;Yoon, Jae-Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.1A
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    • pp.15-26
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    • 2010
  • Quasi-static tests were conducted to evaluate structural performance of precast piers prestressed by bonded prestressing steels. Combinations of prestressing bars and normal reinforcing bars, embedded steel tubes and prestressing strands were used as continuous steels crossing the joints of a precast pier. Main design parameters were steel ratio, magnitude of prestress force, and section details. Flexural strength and energy dissipation capacity of precast columns with higher steel ratio showed better performance due to continuous steels after opening of the joints. Precast piers with embedded members showed stable behavior after reaching maximum loads resulting in higher displacement ductility and energy dissipation capacity increased as the introduced prestress increased. Self-centering behavior at early stages and stress increase of confining reinforcements were observed from highly prestressed columns. Combination of prestressing steels and normal reinforcing bars should be used in design to prevent rapid strength degradation after reaching the maximum load.

Examination of Modified Larinier pass Fishway in Korea (수정 라리니에식 어도의 국내 적용성 검토)

  • Kim, Sun-Joo;An, Min-Woo;Choi, Young-Kyoung;Kyoung, Min-Su
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.452-456
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    • 2006
  • 본 연구는 수정 라리니에식 어도를 조립식으로 개발하여 실제 현장에 적용하기에 앞서 수리모형을 통해 어도 경사와 어도내 조류제 형태(평면형, 경사형, 역경사형)를 3가지로 달리하여 각 형태별 유속을 조사하고 실제 우리 나라 토착 민물고기인 갈겨니, 쉬리, 피라미, 금강모치의 소상능력을 시험하였다. 또한 실제 크기의 목재로 만든 조립식 수정 라리니에식 어도를 제작하여 충청남도 공주시 유구천의 농업용 보에 적용하였으며, 2005년 6월부터 10월까지 모니터링을 하여 수정 라리니에식 어도의 국내 하천 적용성에 대해서 검토하였다. 모형실험결과 수심은 6cm(현장 30cm)일때, 조류재의 형태는 평면형과 경사형, 경사는 1/20, 유속은 0.3-0.4m/s에서 어류가 원활하게 소상하는 것으로 나타났고, 어도내 마련된 휴식부에서는 실제 물고기들의 휴식하는 모습이 관찰되었다. 또한 휴식부의 잠공은 하천 유량 조건이 좋을 때보다 갈수기나 홍수기에 어류가 소상하는 통로의 역할뿐만아니라 저서 생물의 이동통로 역할을 할 수 있을 것으로 생각된다. 따라서 본 어도는 조류재의 형태에 따른 다양한 유속대를 제공하여 다양한 어종이 이용할 수 있을 것으로 판단되며, 조립식으로 되어 시공 및 유지관리가 용이하여 우리나라 하천 상황에 적절한 어도로 판단된다.

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An Evaluation of the Structural Stability of a Clip Type Prefabricated Greenhouse under Strong Wind and Heavy Snow Conditions (조립식 클립형 비닐하우스의 강풍 및 폭설시 구조 안정성 평가)

  • Ro, Kyoung-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.6
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    • pp.3423-3428
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    • 2014
  • Numerical studies were performed to evaluate the structural safety of a greenhouse under both snow and wind loads. In the case of a wind load, fluid-structure interaction (FSI) method was used to consider the local pressure distributions on the greenhouse-induced by aerodynamic characteristics. The results showed that the maximum stress and deformation occur near the junction of pipe supports and rafters of the roof, where connecting clips are installed. Moreover, the wind load is a more severe condition than a snow load. Overall, these results will be used to design a prefabricated connecting clip with easy installation and low maintenance.

Laboratory Loading Test of Light-Weight Prefabricated Plastic Foundation for Sewage Pipe Line (하수관거용 플라스틱 조립식 경량기초의 하중재하실험)

  • Lee, Dong-Hang;Lee, Kwan-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.6
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    • pp.2757-2762
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    • 2012
  • Sewage pipelines are one of important infra-structures. The main reasons of sewage pipelint failure are improper backfill materials and compaction controls in field. Especially, it is very difficult to compact the lower part of circula pipelines. In order to overcome these problems, the prefabricated light-weight plastic foundation was developed. Couple of load-displacement tests were carried out to get the characteristic of failure. From the limited laboratory loading tests, the use of prefabricated light-weight plastic foundation is an alternative to solve the difficulty of backfill materials and compaction control.