• Title/Summary/Keyword: 바닥판

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Analytical Study on the Characteristic of Fatigue Behavior in Connection Parts of Orthotropic Steel Decks with Retrofitted Structural Details in Longitudinal Rib (세로리브 내부 보강상세에 따른 강바닥판 연결부의 피로거동 특성에 관한 해석적 연구)

  • Sun, Chang Won;Park, Kyung Jin;Kyung, Kab Soo;Kim, Kyo Hoon
    • Journal of Korean Society of Steel Construction
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    • v.20 no.1
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    • pp.105-119
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    • 2008
  • In steel deck bridges suffering directly on wheel load according to the number of serviced years, the occurrence of fatigue cracks increases in structural details, which includes the cross section parts of the longitudinal rib and transversal rib, and so on. Through the control method for these fatigue cracks the increased thickness of the steel deck plate or the application of retrofit detail to the inside of the longitudinal rib was observed to be effective. This study suggests structural details for the retrofitted and non-retrofitted longitudinal rib. The target details in this study are the connection parts of the lo ngitudinal and transversal rib, and the slit parts of transverse rib where fatigue cracks were frequently reported in previous studies. In the analyses, detailed structural analyses were performed as parameters, which include the shape, change of size and attached position. From the results the stress reduction in the target details was observed to be larger in the retroffited details. Also, the improvement of fatigue strength is more effective in the retrofitted details with the vertical rib than the bulkhead plate.

Crack Example and Crack Control Method of Very-Early Strength Latex-Modified Concrete (초속경 라텍스개질 콘크리트의 균열발생 사례 및 억제방안)

  • Choi, Pan-Gil;Yun, Kyong-Ku;Lee, Bong-Hak
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.3 s.55
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    • pp.173-180
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    • 2009
  • Very-early strength latex-modified concrete(below ; VES-LMC) was developed for possible early-opening-to-traffic after overlay of bridge deck concrete. The purpose of this study is to analyze the cause of map, transverse and longitudinal cracking in VES-LMC and to provide a control method for minimizing occurrence of cracking. The proposed prevention method against map and transverse cracking was verified by field data. VES cement was modified as the unit cement content was reduced from 390kg/$m^3$ to 360kg/$m^3$. The maximum size of coarse aggregate was increased from 13mm to 19mm. The wire mesh and steel fiber were adopted in concrete mixture. From the results, the proposed prevention method against map and transverse cracking was verified since structural cracking was not occurred until 3 years after overlay.

The Performance Estimation of Rotor in Wind Fence by Rotor Analysis Solver based on Actuator Disk Model (Actuator Disk Model 기반의 로터 해석자를 사용한 방풍 구조물 내부의 로터 성능 예측)

  • Kim, Taewoo;Oh, Sejong;Kang, Hee Jung;Yee, Kwanjung
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.41 no.6
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    • pp.429-439
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    • 2013
  • The purpose of current study is to develop the rotor analysis solver and perform a rotor aerodynamic analysis in the wind fence. To this end, the rotor analysis solver based on actuator disk model was employed. To consider the asymmetric effect of the rotor in the wind fence, the flapping motion analysis was conducted with blade element theory for the effective angle of attack calculation. The validation cases which are the rotor with wall and ground were accomplished by developed solver. The decrease of rotor performance by wind fence was confirmed. The wind fence configuration was suggested which guarantees more than 95% rotor performance compared with the no fence case.

Nonlinear Theory for Laboratory Wave Generation (비선형(非線形) 조파이론(造波理論))

  • Kim, Tae In
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.4_1
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    • pp.137-150
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    • 1992
  • A complete solution, exact to second-order, for wave motion forced by a hinged-wavemaker of variable-draft is presented. A solution for a piston type wavemaker is also obtained as a special case of a hinged-wavemaker. The laboratory waves generated by a plane wave board are shown to be composed of two components; viz., a Stokes second-order wave and a second-harnomic free wave which travels at a different speed. The amplitude of the second-harmonic free wave is relatively large in shallow water and decreases to less than 10% of the amplitude of the primary wave in deep water. Wavemakers with relatively deeper draft (i.e., hinged near the bottom) generate the free waves of smaller amplitude in shallow and intermediate water depths than the wavemakers with shallow draft. However, the opposite is predicted by theory in deep water.

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The Global Educational Applications of the Ecotour Resources in Oceania (오세아니아지역 생태관광자원의 글로벌 교육자료 활용방안)

  • Choe, Jae-Woo
    • Journal of the Korean association of regional geographers
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    • v.13 no.3
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    • pp.355-375
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    • 2007
  • This study explores the geographic characteristics of ecotour resources in Oceania based on the concept of ecotourism along with global education and investigates the global educational applications of eco-resources through a field survey of the Australian Cairns region. The field survey areas are the Green Island within the Great Barrier Reef, Barron Gorge National Park, the Australian Butterfly Sanctuary in Cairns, and the Tjabukai Aboriginal Cultural Park. This case study of the Cairns region is applicable to global education in these aspects: The underwater Observatory and Glass bottom boat in Green Island is used in efficient exploration of ocean ecology; Barron Gorge National Park provides an excellent forest tour with a well-made track, detailed directory, and trained park rangers; the old industrial trains are being recycled for tourism uses; the Australian Butterfly Sanctuary provides various language interpretations and experts to help further visitor's understanding of the surrounding eco-resources; The Aboriginal Cultural Park also utilizes a special program that helps people understand their culture.

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A Study on Constructability Improvement of LB-DECK Panel (LB-DECK 패널의 시공성 향상에 관한 연구)

  • Cho, Hyun-Chul;Lho, Byeong-Cheol;Cho, Gyu-Dae;Choi, Kyu-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.2 s.54
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    • pp.122-128
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    • 2009
  • This study is to improve constructability of LB-DECK construction in site such as inconvenience of main and distribution bars in arrangements LB-DECK Panel which is work is applied to many bridges these days as a permanent formwork. So, the constructability is improved by changing the method of allocation of main reinforcing bar and distribution bar which is reviewed for improving efficiency of design and construction process among the suggested methods. The crack shapes, deflections, and strains under static load of the improvement of LB-DECK Panel are compared and analyzed to former LB-DECK Panel. As a result, 13% of strength compared to before the improvement of LB-DECK Panel, and 10% of strength is increased in the case of slab.

Re-entry Experiences to Socialization of Female Ex-Offender : Based on Grounded Theory Methodology (여성출소자의 사회재진입 경험에 관한 근거이론 연구)

  • Lee, A-Reum;Kim, Mi-Hyun;Lee, Dong-Hun
    • The Journal of the Korea Contents Association
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    • v.17 no.5
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    • pp.388-409
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    • 2017
  • This study was to explore experiences of Female Ex-offender's re-entry process to socialization. For this, 9 female ex-offenders who receive housing support by the Korea Rehabilitation Agency were interviewed and the Strauss and Corbin's ground theory is used to approach to the data. In open coding, 88 concepts, 33 subcategories, and 15categories emerged from the data. In axial coding, central phenomenon were 'indulge in self pity', 'being isolated female ex-offender'. Intervention condition was 'human cooperation system'. Strategies were 'increase the receptiveness', 'establish the foundation'. Consequences were 'finding the stability in the life', 'changing the life direction'. In selective coding, main theme was 'overcome social stigma through changing life-direction and acclimate to society', and four phases were derived from the data. Based upon this results outcome, need of female ex-offender in the process of social transition and their experience were discussed.

주암댐 유역의 민요(民謠)(III)

  • Lee, So-Ra
    • Korean Journal of Heritage: History & Science
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    • v.22
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    • pp.419-460
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    • 1989
  • 화순군을 구(旧)한말까지의 행정구역을 참고로 하여 동복방면, 화순방면, 능주방면으로 나눈다면 남면의 수몰지역은 동복면, 이서면, 북면과 더불어 동복방면에 든다. 동복방면은 섬진강유역의 문화권인데 비해 화순, 능주지방은 영산강유역의 문화권이 된다. 상여소리는 위의 세방면이 서로 큰 차이가 없다. 회닫는 소리가 경기도나 강원도에 비해 현저히 미발달(未發達)된 것은 몇 년 후에 보통 이장을 하는 관계로(토질상, 관습상) 봉분을 다시 파헤쳐야 하기 때문에 회닫을 필요성이 적은 탓으로 해석된다. 북면 원리엔 정월보름에 액막이로 하는 달구질소리가 있다. 모찌는 노래가 따로 없고, 잘 부르질 않는다. 바닥풀소리가 있다. 화순군의 대표적인 논매는 노래는 논매는 양산도이다. 수몰지역의 논매는 노래로는 양산도 및 산아지로고나, 사호소리, 세월이 가 있다. 산아지로고나는 섬진강유역의 대표적인 논매는 노래이며 사호소리는 능주지방 및 화순읍, 동면녹음에선 나오지 않았다. 반면에 세월이는 화순, 능주방면에서 나왔고 동복방면 녹음때엔 안나왔다. 화순군의 논매는 노래로는 그 밖에 아리시고나 마디여, 사하뒤여, 매화타령, 매화가, 노방가, 방애, 더덜기, 난초타령 등이 있다. 아리시고나 마디여는 영산강유역(함평 무안 나주 영암군)이 본고장인 것으로 보이는 논매는 노래로 화순군에서는 북면에서만 나왔다. 장원질 노래로는 사하디여, 풍년가, 두려소리, 뚜룸마, 일반농부가, 양산도, 산아지로고나, 성주, 덩기, 얼쭝덜쭝, 사호소리 등이 쓰인다. 줄메고가는소리로는 "위야허허"가 보성군과 마찬가지로 일반적이며 그 밖에 능주면 만인리의 어기야자자뒤여 가 있다. 기타의 노동요로는 주로 광의의 농요가 수집되었으며 작도소리, 나무내리는소리, 맷돌노래 등이 주목된다. 씨름판 노래로는 썸바타령, 개골, 논매는 양산도 곡(曲)등이 쓰인 것으로 나타났다. 동물요(動物謠)로 거무, 이, 천룡와깨비 등이 수집되었다. 그 밖에 판굿노래, 팽이치기, 연날리기, 등잔가세 등이 주목된다. 논매는 노래는 매화가를 제외하곤 거의가 멕이고 받는 가창방법이며 [표 3]의 46곡(曲)중 1/4 정도만 꺾는 음의 효과(効果)가 있는 곡이다. 솔(라)도레미'의 선법인 것은 44%에 달하며 그중 7할이 기음의 4도윗음인 도에서 종지하되 이를 퇴성한다. 기타에 대해서는 [표 3, 4, 5] 참조.

Analysis of Mechanical Properties of Wood Flours Composites to Improve the Strength of Truck Deck Floor Boards (트럭 Deck Floor Board의 강도향상을 위한 목분복합재의 기계적특성 분석)

  • Yun, Sung-Woo;Go, Sun-Ho;Kim, Hong-Gun;Kwac, Lee-Ku
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.1
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    • pp.24-30
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    • 2019
  • The deck floor of a the cargo truck becomesis damaged and aged due to the continuous loading of the loading cargo and external environmental factors. Floor boards made of wood and metal are often used. In the case of wood, the cost is high due to the use of imported wood, and the strength is easily deterioratesd due to environmental factors. In the case of metal materials, the durability is higher than that of wood, but problems are raised due to the effect of major factors that hinder the weight reduction, and the effects of corrosion. In order to replace this stucturestructural design, this study proposed a wood fiber composite using natural raw materials. Woody composites are being used as environmentally and friendly exterior materials with the combined advantages of plastic, and wood,; low cost and low density. However, due to the nature of the woody composites, the properties are differentdiffer depending on the contents of the matrix, reinforcing agent, additives, compatibilizer, etc. In this study, we investigate these problems through analysis of the microstructure and mechanical properties according to proper content and injection molding conditions. As a result, it is considered that the wood deck composite can replaced the current Deck Floor Boardreplace current deck floor boards through continuous continued research and results of this study.

Time-dependent Parametric Analyses of PSC Composite Girders for Serviceability Design (사용성 설계를 위한 PSC 합성거더교의 시간의존적 변수해석)

  • Youn, Seok-Goo;Cho, Sun-Kyu;Lee, Jong-Min
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5A
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    • pp.823-832
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    • 2006
  • To ensure the serviceability requirements of PSC composite girder bridges, it is essential to predict the stresses and deformations of the structure under service load conditions. Stresses and deformations vary continuously with time due to the effects of creep and shrinkage of concrete and relaxation of prestressing steel. The importance of these time-dependent effects is much more pronounced in precast prestressed concrete structures built in stages than in those constructed in one operation. In this paper, time-dependent analyses for PSC composite bridges using 30m standard girders have been conducted considering with the variation of the times of introducing initial prestressing forces and casting concrete. A computer program has been developed for the time-dependent analysis of simple or continuous PSC composite girders and parametric studies are conducted. Based on the numerical results, it is investigated the long-term behaviors of PSC composite girder bridges and discussed the limitations of the current codes for the prestress loss.