• Title, Summary, Keyword: 프리캐스트

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Analytical Modelling of Construction Structure Controlling Camber of Long-width Exterior Precast Panel (장폭 외측 프리캐스트 패널 캠버 조정을 위한 가설구조의 해석모델)

  • Won, Tae-Gun;Won, Dae-Yon;Kim, In-Soon;Lim, Yun-Mook
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.293-296
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    • 2010
  • 일반 교량에 주로 사용되는 콘크리트 바닥판 시공을 위해서는 동바리, 거푸집 등을 설치하고 철근 배근 후 콘크리트를 타설하는 방법이 사용되어왔다. 그러나 기존 콘크리트 바닥판 시공은 계절 및 기후의 영향을 많이 받는다. 또한 시공과정에서 많은 인력이 요구되고 시공 안전성 확보를 위한 노력이 필요한 실정이다. 이러한 문제점을 극복하기 위하여 최근에 프리캐스트 바닥판을 이용한 교량 시공이 늘어나고 있는 추세이다. 프리캐스트 바닥판은 공장에서 선제작한 후 현장에서 조립하여 시공한다. 따라서 프리캐스트 바닥판 시공은 계절 및 기후의 영향을 최소화 하여 공기를 단축할 수 있고, 공장제작에 따른 양호한 품질도 보장된다. 또한 인력이 적게 요구되면서 시공 안전성도 확보할 수 있다. 그러나 이러한 기존의 프리캐스트 바닥판은 패널의 폭이 좁고 외측 캔틸레버부의 시공 시 별도의 지보공이 필요한 단점을 갖고 있었다. 이러한 단점을 보완하기 위해 장폭 외측 프리캐스트 바닥판이 제안되었다. 장폭 외측 프리캐스트 바닥판은 패널의 폭을 늘려서 장폭의 바닥판을 만들고, 가설구조물을 이용하여 지보공 없이 시공이 가능하게 고안되었다. 본 연구에서는 장폭 외측 프리캐스트 패널 캠버 조정에 사용 될 가설구조의 현장적용을 위하여, 실험 후 유한요소해석을 수행하여 비교 및 검증하였다.

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Flexural Strength Estimation of Half-Depth Precast Concrete Composite Slab Manufactured by the Long-Line Method (롱라인 공법으로 제작한 반단면 프리캐스트 콘크리트 합성 슬래브의 휨강도 평가)

  • Choi, Jin-Woo;Seo, Su-Hong;Joo, Hyung-Joong;Yoon, Soon-Jong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.4
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    • pp.48-56
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    • 2013
  • Prestressed concrete (PSC) members are readly available in civil engineering applications due to the convenience of construction and easy of quality control in the manufacturing process of the member. Especially, half-depth precast concrete composite slab, which is one of the PSC flexural members is developed recently using the long-line method. The half-depth precast concrete composite slabs are composed of the precast concrete and the in-situ concrete placed at the site. In this paper, we present the results of experimental investigations pertaining to the pretensioning efficiency and the flexural behavior of half-depth precast concrete composite slab which is made of precast PSC manufactured by the long-line method. In the long-line method, the pretensioned precast member is manufactured simultaneously, by tensioning tendons at once. In addition, we suggest the equation that can estimate the flexural strength of half-depth precast concrete composite slab reasonably by considering the effects of rebar embedded in the precast PSC flexural member.

Mechanical behaviour of tunnel liner using precast segment reinforced by rib (리브 보강 프리캐스트 터널 Liner의 역학적 거동 특성)

  • Lee, Gyu-Phil;Lee, Sung-Won;Shiin, Hyu-Soung;Hwang, Jae-Hong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.10 no.3
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    • pp.295-302
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    • 2008
  • Due to the limitation of construction efficiency and structural safety, the application of the high covering and wide width tunnels was limited prior to the introduction of precast cut and cover tunnels. Therefore, a cut and cover tunnel structure with rib reinforcement is proposed to mechanically improve the safety on condition of high covering and wide width tunnel. In this study, large-scale experiments are carried out to examine the mechanical behavior of the cut and cover tunnel structure with rib reinforcement under static load condition. Based on the results obtained from this study, the ultimate load of tunnel structure increases to about 3.3 times by rib reinforcement. Consequently, safety of tunnel structure increases compared to non-installed cases due to confining crown part by rib reinforcement.

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Static Tests on Transverse Joints of Precast Prestressed Concrete Bridge Deck (프리스트레스를 도입한 프리캐스트 콘크리트 교량바닥판 연결부에 관한 정적 실험)

  • 정철헌;김영진;김성운;박칠림
    • Magazine of the Korea Concrete Institute
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    • v.10 no.2
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    • pp.109-117
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    • 1998
  • 중트럭통행으로 인한 철근콘크리트 교량바닥판의 열화는 교량구조물을 유지보수하는데 있어서 심각한 문제중 하나이며, 프리캐스트 바닥판을 이용한 교량바닥판의 시공 및 교체 방법이 실용적이며, 효과적인 방법으로 인식되고 있다. 본 연구에서는 프리캐스트 바닥판 사이 연결부에 대한 정적실험을 수행하여 실험부재의 탄성영역 및 극한 상태하에서 프리캐스트 바닥판 사이 교축직각 방향 연결부의 강성 및 강도를 평가하였다. 정적실험결과, 무수측 모르나트를 채움재로 사용한 프리캐스트 바닥판 사이 교축방향 연결부는 교축방향으로 적정량의 프리스트레스를 도입함으로서 일반 현장타설 철근콘크리트 바닥판에 비해서 균열에 대한 사용성이 향상되는 것으로 나타났다.

Analysis on Shapes of Shear Pocket for the Full-Depth Precast Slab (프리캐스트 바닥판의 전단포켓 형상에 관한 해석 연구)

  • Han, Sang Yun;Lee, Man Seop;Lee, Seung Rok;Kang, Young Jong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.5A
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    • pp.817-822
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    • 2006
  • Post-tensioning the full-depth precast slab longitudinally is to eliminate the tensile stresses in the transverse joints and to prevent any leakage through the joints. When the prestressing is applied to full-depth precast slab which does not composite steel girder, stress concentration occurs at the corners of shear pocket, and compressive stress is not uniformly distributed in the section of precast slab. In this paper, full-depth precast slabs using four different shapes of shear pockets are analyzed by commercial finite element program. Round type of shear pockets is superior to reduction in stress concentration.

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Early-Age Performance of Intersection Pavement Constructed Using Precast Concrete Panels (프리캐스트 패널을 이용한 교차로 구간 도로 포장 초기 공용성 분석)

  • Oh, Han-Jin;Hwang, Ju-Hwan;Kim, Seong-Min;Rhee, Suk-Keun;Park, Sung-Ki
    • International Journal of Highway Engineering
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    • v.13 no.2
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    • pp.115-123
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    • 2011
  • This study was conducted to investigate the early-age behavior and performance of precast pavements constructed by replacing existing asphalt pavements for an intersection in urban bus only lanes. The monitoring items included level differences between asphalt pavement and precast panels at the beginning and ending locations of the precast pavement, level differences and joint widths between precast panels, precast panel settlement, and skid resistance of the panel surface. At a certain time after the construction, the diamond grinding method was applied and its effect was also investigated. The monitoring results showed that as time went by, the panel level, joint width, settlement, and skid resistance were not much varied. That implied the stable sustaining of external loads by the precast pavements. In addition, it was verified that employing diamond grinding could reduce the level differences between precast panels.

Mechanical behaviour of rib-reinforced precast tunnel liner according to variable rib-reinforcement shapes (프리캐스트 터널 Liner의 리브보강 형상변화에 따른 역학적 거동 특성)

  • Lee, Gyu-Phil;Lee, Seong-Won;Hwang, Jae-Hong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.11 no.3
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    • pp.265-275
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    • 2009
  • Due to the limitation of construction efficiency and structural safety, the application of the high covering and wide width tunnels was limited prior to the introduction of precast rut and cover tunnels. Therefore, a cut and cover tunnel structure with rib reinforcement is proposed to mechanically improve the safety on condition of high covering and wide width tunnel. Therefore, a technical problem that can provide a response similar to the actual filling conditions is analyzed by the finite element analyses, moreover, the mechanical behaviour of developed rib-reinforced precast tunnel liner through a large-sized model test will be investigated. The ultimate load of the developed rib-reinforced precast tunnel liner shows a 3% reduction compared to existing rib-reinforced precast tunnel liner, especially, the section of rib-reinforcement decreased to 55% compared to it of existing. Therefore, the stability of tunnel structure can be significantly improved through the developed rib-reinforced precast segment.

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Jacking Force and Camber for Precast Concrete Slab Reinforcing (프리캐스트 콘크리트 슬래브 보강을 위한 잭킹력과 솟음)

  • Lho, Byeong-Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.2
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    • pp.43-48
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    • 2021
  • Precast concrete can be used to reduce construction period and enhance construct ability. However structural problems could be occurred due to the wrong application of boundary condition and misunderstanding of structural behavior in the process of segmentation of original structure system. I experienced a serious deflections and cracks due to the increase of bending moment and creep after the construction of precast concrete slab, and we learned that this is from the misunderstanding of support conditions and structure behaviors of precast slab panel. Two support columns under the precast slab are inserted to reduce the bending moment, and the camber according to jacking force should be estimated for the structural safety during the reinforcing work. A proper support condition and the flexural stiffness of precast concrete slab were applied to check the deflection and crack for existing structure by inverse analysis, and we can estimate the camber according to jacking force of the precast concrete slab, and suggest a method to make safe structure.

Nonlinear Finite Element Analysis of Precast Pier Coping (프리캐스트 교각 코핑부의 비선형 유한요소해석)

  • Cheon, Ju-Hyoun;Kim, Tae-Hoon;Kim, Young-Jin;Shin, Hyun-Mock
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.153-154
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    • 2010
  • For completing an fully optimized and prefabricated substructure system of bridge, developing pier of precast segment PSC which equip the connection structure of shear resistance and precast foundation are conducted previously. Specimens of coping of bridge were developed and customized, and experiments were performed. The result of the experiment through the result from a reliable non-linear analysis program (RCAHEST) were compared and analyzed and evaluated the stability and ultimate behavior of coping of precast pier.

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