• Title/Summary/Keyword: 서까래 파이프

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Change of Tensile Strength for Rafter Pipes of Plastic Greenhouse according to Elapsed Period (경과년에 따른 비닐하우스 서까래 파이프 인장 강도 변화)

  • Song, Hosung;Lim, Seong-Yoon;Ryu, Hee-Ryong
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2017.04a
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    • pp.130-130
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    • 2017
  • 비닐하우스의 골조를 구성하는 파이프는 부식을 방지할 목적으로 아연도강관을 사용한다. 그러나 시간이 지남에 따라 아연도금량 감소와 여러 외부 환경인자 등에 의하여 부식이나 침식이 진행되어, 외관상 녹이 생기고 강도와 연신율 등이 감소하게 된다. 이는 비닐하우스 전체의 내구성을 저하시키는 요인으로 작용하게 되는데, 이를 평가하기 위한 방법이나 기준은 미비한 실정이다. 이에 본 연구에서는 농업시설의 내구성을 평가하기 위한 방법의 하나로 각기 다른 경과년수를 갖는 비닐하우스로부터 채취한 서까래 파이프의 인장 시험을 실시하였다. 인장 시험에 사용된 서까래 파이프는 (구)시설원예시험장에 설치되어 있는 비닐하우스에서 경과년별로 채취하였으며, 지중매설부와 지상노출부로 구분하여 시편을 제작하였다. 인장 실험 결과 서까래 파이프의 경과년이 오래될수록 시편의 인장 강도는 작아지는 경향을 보이고 있으나, 파단연신율은 경과년과 연관성을 찾아보기 어려운 것으로 나타났다. 그리고 동일한 경과년을 갖는 서까래 파이프 시편에서 지중매설부의 인장 강도와 파단연신율이 지상노출부에 비해 대체로 작게 측정되었으며, 경과년이 증가할수록 인장 강도의 감소폭이 커지는 경향을 보이는 것으로 나타났다.

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The Optimum Specification of Pipes in Rain-Sheltering Greenhouse with Roof Vents for Large-Grain Grapevine Cultivation (대립계 포도 천창개폐형 비가림하우스의 최적 파이프 규격)

  • Yum, Sung-Hyun;Yun, Nam-Gyu;Kim, Gyeong-Won;Lee, Sung-Hyoun;Cho, Yong-Ho;Park, Seo-Jun;Park, Mun-Kyun
    • Journal of Bio-Environment Control
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    • v.16 no.4
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    • pp.275-283
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    • 2007
  • This study was carried out to: (1) analyze structural stability of representative rain-sheltering greenhouses for large-grain grapevine cultivation with widths of 3.6 m and 5 m in case of using the existing pipe for agriculture; (2) present the optimum specification of pipes in the greenhouse with a width of 5 m under the condition of using the pipe of which ultimate strength has been above $400N{\cdot}mm^{-2}$; (3) evaluate stability and also present the optimum specification of pipes as eaves height was augmented. The above analyses were done for greenhouses with roof vents and also with a main-column interval of 3 m and a rafter interval of 60 cm. First, the existing 3.6 m greenhouse with a rafter of ${\Phi}25.4{\times}1.5t@600$ was stable far a snow-depth of 35 cm but unstable for a wind velocity of $35m{\cdot}s^{-1}$. Meanwhile the existing 5 m greenhouse with the same rafter was not stable for a wind velocity of $335m{\cdot}s^{-1}$ as well as a snow-depth of 35 cm. This meant that existing greenhouses had to be reinforced to secure stability. Second, the specification of pipes, especially rafter, could be classified as two cases. One had a structural stability at a safe wind velocity of $35m{\cdot}s^{-1}$ and a safe snow-depth of 40 cm for which stability the rafter had to be ${\Phi}31.8{\times}1.5t@600$, and the other had a stability at $30m{\cdot}s^{-1}-35cm$ at the specification of rafter ${\Phi}25.4{\times}1.5t@600$. Finally, eaves height had a significant effect on safe wind velocity. But it had little influence on safe snow-depth. The results showed that the specification of side-wall pipes had to be reinforced for the safe side velocity accord-ing to the increment of eaves height and similarly the specification of fore-end post far the safe fore-end velocity.

Uplift Capacity of Pipe Foundation for Single-span Greenhouse (단동 온실용 파이프 기초의 인발저항력 검토)

  • Choi, Man Kwon;Yun, Sung Wook;Kim, Ha Neul;Lee, Si Young;Yu, Chan;Yoon, Yong Cheol
    • Journal of Bio-Environment Control
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    • v.24 no.2
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    • pp.69-78
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    • 2015
  • In order to provide design data support for reducing gale damage of single-span greenhouses, this paper experimentally evaluated the uplift capacity of a rafter pipe and continuous pipe foundation (anti-disaster standard), usually used for single-span greenhouses according to compaction ratio, embedded depth, and soil texture. In the reclaimed soil (Silt loam) and the farmland soil (Sandy loam), the ultimate uplift capacities of rafter pipe were 72.8kgf and 60.7kgf, respectively, and those of continuous pipe foundation were 452.7kgf and 450.3kgf, respectively at an embedded depth of 50cm and compaction rate of 85% (the hardest ground condition). The results showed that the ultimate uplift capacity of continuous pipe foundation was significantly improved at more than 6 times that of the rafter pipe. The soil texture considered in this paper had a sand content of 35%~59% and a silt content of 39%~58%, and it was shown that the ultimate uplift capacity did not have a significant difference depending on soil texture, and these results show that installing the rafter pipe and continuous pipe foundation while maintaining appropriate compaction conditions can give an advantage in securing stability in the farmland of greenhouses without significantly being influenced by soil texture. Based on the results of this paper, it was determined that maintaining a compaction rate above 75% for the continuous pipe foundation and above 85% for the rafter pipe was advantageous for securing stability in greenhouses. Especially when continuous pipe foundation of anti-disaster standard was applied, it was determined to be significantly advantageous in acquiring stability in greenhouses to prevent climate disaster.

Evaluation of Structural Stability of a Simple-typed Cultivation Facility for Growing Pleurotus ostreatus (간이 느타리재배사의 구조 안전성 평가)

  • Yum, Sung-Hyun;Yun, Nam-Kyu;Kim, Chul-Soo
    • Journal of Bio-Environment Control
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    • v.17 no.3
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    • pp.181-187
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    • 2008
  • The structural stability of a simple-typed cultivation facility with a width of 5.6 m for growing Pleurotus ostreatus was analyzed by modeling the facility as three-dimensional steel frames. The computation was done by using the finite element analysis program, ANSYS and the criterion of determining structural stability was based on the allowable stress design (ASD). The computational results showed that the structure with a straight-typed bed column was more stable than those with other types of bed columns against snow depth but there was little difference against wind velocity. As results, the interval of rafter had a more influence on safety wind velocity than that of bed column, while the interval of bed column was more important to safety snow depth. Finally the bed column against buckling was stable in all cases considered in this paper.

Improvement of ventilation method in single-span type vinyl-house (단동형 비닐하우스의 환기방법 개선 연구)

  • Kim, Hyun-Hwan;Jeon, Hee;Lee, Si-Young;Kwon, Young-Sam
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1998.05a
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    • pp.174-177
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    • 1998
  • 단동형 비닐하우스의 규격은 대부분 폭 5-6m, 하우스높이 2.4m정도로 아연도금파이프 ø22mm, ø25mm를 이용하여 아치형이나, 돌출형(복숭아형) 형태로 서까래간격 60cm에서 120cm까지 시공되어 있으며 남부지역에서는 서까래 간격이 넓게 시공되는 것이 일반적이다. 최근에는 하우스 환기를 위해 측면 권취 뿐만 아니라 하우스의 천장에 상품화된 연통형(굴뚝형) 환기구를 단동형 비닐하우스에 많이 이용되고 있으며 시설내환경을 조절하고 있다. (중략)

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Greenhouse structural analysis according to various section type (온실 서까래용 파이프의 단면형상에 따른 구조적 특성 변화)

  • 윤남규;이시영;김학주;남윤일;김문기;유인호
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 2002.11a
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    • pp.289-292
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    • 2002
  • 최근들어 파이프 골조의 온실 구조는 해마다 강풍이나 적설 둥으로 인한 파손으로 막대한 경제적 손실을 입고 있으며, 이러한 피해는 환경조절 및 자동화 설비의 설치에 직접적인 영향을 주는 중요한 요인이므로 시설의 구조역학적인 연구가 지속적으로 이루어져야 한다. 그러나 국내에서는 1990년대 초반 온실의 구조안전 및 구조설계 기준 설정, 자재의 규격화 및 표준화에 관한 연구가 일부 수행된 바 있으나, 파이프 골조의 온실은 구조물로서의 공학적 설계나 유지관리에 대한관심이 부족하여 시설의 구조역학적인 연구가 거의 이루어지고 있지 않는 실정이다. (중략)

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Development of a Temporary Pole Supporting System to Protect the Plastic Houses from Heavy Snow Damage (비닐하우스 폭설피해 방지용 가지주 장치의 개발)

  • 남상운
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 2001.11a
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    • pp.65-70
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    • 2001
  • 우리 나라의 온실 설치 면적은 1999년말 현재 51,200ha에 이르고 있으며 그 중 유리온실이 363ha로 0.7%, 철골 경질판 온실이 125ha로 0.2%이고, 아연도강관을 사용한 비닐하우스가 50,712ha로 99.1%를 차지하고 있다. 파이프 골조의 비닐하우스는 대부분 아치형의 지붕 모양을 하고 있으며, 바람에는 비교적 강하나 적설에 약한 구조이다. 전국적으로 가장 널리 분포하고 있는 직경 25.4mm, 두께 1.5mm의 파이프를 사용한 폭 6m의 단동 온실의 경우 서까래 간격 60~80cm일 때 안전 적설심은 10~14cm 정도에 불과하다(남 등, 2000). (중략)

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A Study on the Improvement of Greenhouse Frame to Bear the Heavy Snow (적설하중 증가에 대비한 비닐하우스 골조 성능의 개선 연구)

  • Jung, Hyunjin;Yang, Sanghyun;Lee, Taehee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.3
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    • pp.2242-2248
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    • 2015
  • The damages from greenhouses collapsing due to heavy snowfall in winter are increasing, and the current frames of greenhouse are required to be improved. This study was conducted to seek solutions to improve intensities of greenhouse frame to bear heavy snows. We investigated a structural safety of greenhouses by calculating axial force, bending moment and combined stress when snow load was increased up to 30% of the current standard ground snow load of the conventional greenhouse types (07-single type 3, 07-single type 18) in the three regions (Gyeongju, Sokcho, and Gangneung) where were most damaged by recent heavy snows. In addition, we determined what structural type was most efficiently bear snow loads by measuring the differences between the load bearing strength according to the changes of tube diameter and thickness or the rafter spacing of greenhouses circular pipe. MIDAS GEN program was used in the analysis. As a result, with the snow load increase of 30%, greenhouse in Gyongju was still safe, but in Sokcho was at a risk, and in Gangneung was possible to be collapsed even in the current snow load. Increased pipe diameter than increased pipe thickness was more efficient in terms of improved performance of greenhouse structure. Accordingly, it is suggested to revise standards of greenhouse to increase pipe diameter of rafter for minimizing damages by heavy snow.

Effect of the Pipe Joint on Structural Performance of a Single-span Greenhouse: A Full-scale Experimental and Numerical Study (파이프 이음부가 단동온실 구조성능에 미치는 영향: 실대형 실험적 및 해석적 연구)

  • Shin, Hyun Ho;Ryu, Hee Ryong;Yu, In Ho;Cho, Myeong Whan;Seo, Tae Cheol;Kim, Seung Yu;Choi, Man Kwon
    • Journal of Bio-Environment Control
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    • v.30 no.4
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    • pp.410-418
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    • 2021
  • This study was conducted in 8.2m wide single-span greenhouse to investigate the effect of presence or absence of rafter steel pipe joint and foundation conditions on greenhouse structural performance. Structural performance was evaluated by static loading test using the structural performance evaluation system for single-span greenhouse. The measured displacement was compared with the predicted result by numerical analysis. The displacement of each measurement location showed a significant difference regardless of the conditions of the foundation and presence or absence of rafter steel pipe joint. Compared to the hinge conditions, the difference in structural performance of the greenhouse in the fixed conditions was seen to be relatively large. The difference in structural performance according to presence or absence of rafter steel pipe joints, the lateral stiffness of the joint was 8.1% greater.

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.