• Title/Summary/Keyword: Rafter

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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.

Test Methods for Evaluation of Slip-Resistance Force of Clamp for Plastic Greenhouse (플라스틱 온실 죔쇠의 미끄럼 저항력 평가를 위한 실험 방법)

  • Choi, Man-Kwon;Song, Ho-Sung;Cho, Myeong-Whan;Yu, In-Ho;Shin, Young-An;Lim, Seong-Yoon;Ryu, Hee-Ryong
    • Journal of Bio-Environment Control
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    • v.25 no.3
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    • pp.193-199
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    • 2016
  • The research discussed experimental results on slip resistance force of rafter-purlin connection of plastic greenhouse and suggested a test method for evaluating slip resistance performance of the connection. Slip resistance forces were measured by four kinds of constraint conditions for specimens, for example, fixing or rolling the end of specimen. According to tests, it is noticed that constraint condition is able to significantly affect the slip resistance force. From a post-hoc comparison result, slip resistance force of test under fixing ends condition was larger than those under the other three constraint conditions. But the slip resistance force results in the fixing ends condition had greater measure of dispersion and three times of standard deviation than those from other constraint conditions. Based on the results obtained, effect of constraint condition for specimen on the slip test should be studied to enhance reliability of evaluation test of the slip resistance performance.

Evaluation on the Behavioral Characteristics of Plastic Greenhouse by Full-scale Testing and Finite Element Analysis (재하시험과 유한요소해석에 의한 플라스틱 필름 온실의 거동특성 분석)

  • Ryu, Hee Ryong;Lee, Eung Ho;Cho, Myeong Whan;Yu, In Ho;Kim, Young Chul
    • Journal of Bio-Environment Control
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    • v.21 no.4
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    • pp.459-465
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    • 2012
  • This study analyzed the effect of semi-rigid rafter-purlin cross-linking connection and driven steel pipe base on the static behavior of plastic greenhouse (PG). To promote the time and cost efficiency of the assembly process, each cross-linking connections of space arch type grid that consists of rafter and purlin is linked with steel-wire buckles, and each end of the rafters was driven directly to the ground to support the PG structure. However, in the design process, cross-linking connections and bases are idealized by being categorized as fully rigid or frictionless pinned, which does not appropriately reflect actual conditions. This study takes a full-scale loading test of PG and analyzes the effect of member cross-linking connections and driven steel pipe base on the behavior of a structure. The analysis provided a basis for determining the rigidity factor of member cross-linking nodes needed for finite element analysis, and the reliability of the result regarding the static behavior of PG.

Sustainable Elements in Transformation of Dwelling Space of Urban Traditional Houses in Cheongju City of Korea (청주 도시한옥 주공간의 변용에 나타난 지속적 요소에 관한 연구)

  • Min, Sae-Rom;Kim, Tai-Young
    • Journal of the Korean housing association
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    • v.22 no.5
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    • pp.71-80
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    • 2011
  • The purpose of this study is to investigate the present status of dwelling spaces and deduct sustainable elements in transformation of them by comparing the restored drawings with the surveyed drawings focused on traditional houses that exist in the urban area of cheongju city in Korea. In alteration and extension of these traditional houses, scale of a private room became larger as it has been connected and expanded, the exterior main hall (Daecheong) became the interior living room, and the conventional kitchen was westernized and changed from K type to DK or LDK type. The toilet located at outside was installed by the attached aisle (Toetgan) inside and the existing room. The extension was completed with equipments, storage space, and rental accommodation. The conservative and sustainable elements in the various transformation of them are as follows. Firstly, it was to maintain 3 rooms such as main room (anbang)-main hall (daecheong)-detached room (gunnunbang). Secondly, it was to sustain the circulation of kitchen and arrangement of the - type worktable even though it was westernized. Thirdly, extension of storage space was completed less than 600 mm within the eaves. Although there were functionally and structurally many changes in 18 houses, 4 houses had maintained wooden floor of main hall, 5 houses long planked wooden floor of the attached aisle, and 12 houses rafter ceiling of the main hall and the attached aisle.

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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A Study on the Attractive Items of Hanok in Urban Area focused on Preceding Studies (선행연구에 나타난 도시한옥의 매력 요소에 관한 연구)

  • Min, Sae-Rom;Kim, Tai-Young
    • Journal of the Korean Institute of Rural Architecture
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    • v.14 no.3
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    • pp.61-68
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    • 2012
  • The purpose of this paper is to derive attractive items of 'Hanok' in order to preserve 'Hanok' in urban area, focused on the 13 preceding studies which have got in respect of image, satisfaction, preference, awareness and advantage of 'Hanok' in urban area revolved around the latest studies. This study is analysis of questionnaire items and results of 13 preceding studies. And attractive items are classified with general and overall survey items, advantage of 'Hanok' in urban area, and image of Hanok-density urban area. These can also be classified with 5 items which are space, health, material, form, and image of 'Hanok' in urban area. As a result, Space items are composed with 'use of a space', 'cosiness', 'garden' and 'floor and ondol(korean floor heating system). Health items are composed with 'lighting and ventialtion', 'a sense of the season' and 'natural material'. Material items are composed with 'natural beauty', 'wooden', 'changhoji(traditional Korean paper made from mulberry bark for doors and windows) and hanji(traditional Korean paper handmade from mulberry trees), 'rafter' and 'new materials'. Form items are composed with 'attractive appearance', 'simply decoration' and 'traditional elements'. Image items are composed with 'crowding', 'traditionality and historicity', 'dichroism' and 'warmth'.

Fashion cultural product design applying cultural resources of Iksan (익산지역 문화 자원을 활용한 패션 문화상품 디자인 개발)

  • Kim, Hye Kyung;Chu, Mi Kyung;Hong, Jeong-Hwa;Jeon, Hee-Kwan
    • The Research Journal of the Costume Culture
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    • v.22 no.4
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    • pp.555-564
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    • 2014
  • This study aims to develop motifs and patterns for fashion cultural product designs in order to promote the Iksan Seodong Festival, which is the most representative festival in Iksan region. The motifs and patterns developed in this study can be used to introduce the distinct traditional culture depicting the legendary Seodong tale. This study used Adobe Illustrator CS4 and Adobe Photoshop CS4 to reconstruct the lotus motifs found from the green-oiled-lotus-motif rafter tile, the atrifact from Iksan Mireuksaji Museum. This lotus motif and the motif based on the Iksan City's logo were applied to a repeating pattern with colorways using the CMYK found from the Iksan city's logo. A total of 24 product designs, including 8 necktie designs, 8 scarf designs, and 8 T-shirts designs, were presented for fashion cultural products. The designs developed in this study can promote not only the local Iksan culture but also the national image of Korea on a global scale.

A Study for the Expression of Korean Tradition in Interior Design-Focus on Korean restaurant- (실내디자인의 한국전술표현에 관한 연구-한식당을 중심으로-)

  • 김형대
    • Korean Institute of Interior Design Journal
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    • no.6
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    • pp.15-20
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    • 1995
  • In this paper, a strategy for utilizing the Korean tradi-tional spaces and interior design elements in inner space in order to express Korean-style interior design has been studied. Characteristics of Korean tradition was gathered from literatures in two categories; space and el-ements. Space again has been studied in detail in the area of split, continuity, hierarchy, elasticity, dynamics. And study of elements includes floor, wall, ceiling, dan-chung, lattice, laytiles on a roof, rafter, extended eaves, the line of eaves. 30 Korean restaurants were selected, analysed and compared with literature review. Based on the compari-son, a strategy for proper expression and utilization of Korean tradition is suggested. In the process of compari-son, current status of implementation and problems were found. Traditional elements are used in about 50% of Korean restaurants located in hotels, and 25% of those located in department stores. With the survey and other professional's opinions, an implementation plan is suggest-ed as follows; 1. Succession design method of tradition should use main-ly amelioration method and use copy and partly abstraction method. 2. Expression of tradition has to include all of space, ele-ments, and decoration. In space structure, Korean tra-dition space structure must be applied. 3. In order to design with feeling of Korean tradition, various different Korean elements have to be used. 4. In order to express high quality design, high-quality elements has to be used.

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Experimental Analysis on Yield Strength of Pipe Connectors and Joints for Pipe Framed Greenhouses (파이프 골조 온실의 조립 연결구 내력 시험)

  • 남상운
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.43 no.6
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    • pp.113-119
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    • 2001
  • Experiments on the yield strength of pipe connectors made of metal wire, joint pins, pole pipes, multi span insertion joints, and T-clamp joints used in pipe houses were conducted. The strength of connections of a pipe connector made of metal wire was adequate but it had a big difference according to loading direction. Therefore as it is installed, its direction should be taken into consideration. The collapse load of pipes connected with a joint pin was lower than that of single pipes. In the part of frame member at which the great bending moment occurs, the use of joint pin should be avoided. Also experimental results showed that pole pipes for use in a part of frame buried under the ground were safe, and the strength of multi span insertion joints should be increased. The resistant moment of T-clamp was about 13.7% of a single pipe. In case that the external forces acting on left and right rafter are different. a unsymmetrical rotational force is produced at the multi span joint. If it is expected that the actual bending moment on the multi span joint is larger than resistant moment of T-clamp, a reinforcement to safely resist the rotational force is required.

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Development of a Gable-roofed Prefabricated Pipe-house for Improvement of Snow Endurance (내설성 향상을 위한 지붕형 조립식 파이프하우스의 개발)

  • Yang, In-Kyoo;Nam, Sang-Woon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.51 no.3
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    • pp.71-78
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    • 2009
  • Pipe section of bending part at the arch type pipe-house showed an ellipse with oblateness of 0.076 on the average. Flexural rigidity of bending part decreased by average 6.3% than that of an original round shape section. The deflection of arch type pipe-house measured by model experiments showed much bigger than the result of structural analysis. In case of arch type pipe-house, we supposed that the decrease of flexural rigidity for the bending part of pipes had an effect on deflection of roof under the working load. This effect should be considered in the structural analysis. Bending resistance of gable type pipe-house used a prefabricated connector which developed in this study showed about $1.5{\sim}1.8$ times stronger than that of the existing arch type or gable type processed bending. Therefore, we supposed that the gable-roofed prefabricated pipe-house is safer than arch type or bent gable type in case of heavy snowfall. According to house scales and section properties of steel pipe in use, safe snow depths and rafter intervals were presented for design of gable-roofed prefabricated pipe-house. Their standards were established in the range of the durable models recommended by RDA, and the comparative examinations were conducted by means of structural analysis. It was evaluated that the developed greenhouse model had a high applicability in the field.