• 제목, 요약, 키워드: Slab joint

검색결과 198건 처리시간 0.046초

Numerical study of stress states near construction joint in two-plate-girder bridge with cast-in-place PC slab

  • Yamaguchi, Eiki;Fukushi, Fumio;Hirayama, Naoki;Kubo, Takemi;Kubo, Yoshinobu
    • Structural Engineering and Mechanics
    • /
    • v.19 no.2
    • /
    • pp.173-184
    • /
    • 2005
  • For reducing construction cost, two-plate-girder bridges are getting popular in Japan. This type of bridge employs a PC slab, which is often cast-in-place. In such a case, concrete is not usually cast over the whole slab at one time: some portions are constructed earlier than the rest. Therefore, a construction joint is inevitably created. Due to the drying shrinkage of concrete, tension stress may occur in concrete slab. High tensile stress can be expected near the construction joint where concretes with different ages meet. Moreover, prestressing is not applied over the whole length of slab at one time. This may also serve as a source of tensile stress in the slab. Thus there is a chance that cast-in-place PC slab, especially near the construction joint, may be subjected to tensile cracking. In the present study, stress states near the construction joint in the cast-in-place PC slab of a two-plate-girder bridge are investigated numerically. The finite element method is employed and the three-dimensional analysis is conducted to see the influence of dry shrinkage and prestressing. The stress states in the PC slab thus obtained are discussed. The simplified model of a plate girder for this class of analysis is also proposed.

연속 프리캐스트 콘크리트 슬래브궤도에서의 온도하강에 따른 슬래브 이음매 개구량 해석 (Analysis of Slab Joint Opening Due to Temperature Drop in Continuous Precast Concrete Slab Track)

  • 장승엽;이정완
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.1659-1663
    • /
    • 2011
  • Precast concrete slab track is a track structure to be installed by transporting and assembling precast concrete slabs manufactured at the factory. This method can improve concrete quality, provide easy maintenance and reduce construction time, compared with in-situ concrete track. However, the concrete slabs being continuously connected in longitudinal direction, due to the temperature change between summer and winter, the openings at slab joints have occurred. Thus, in this study, to identify the cause of this opening of slab joint, the joint opening caused by temperature drop in the longitudinally continuous precast concrete slab track has been predicted using three-dimensional finite element analysis, and compared with field measurements. Based on the proven model, the slab joint opening, and the stress pattern of concrete slab and steel reinforcement according to concrete slab-base friction properties, concrete-reinforcement bond properties, and prestressing were analyzed.

  • PDF

복층터널 중간슬래브 설계 기준 마련을 위한 기본 거동 특성 분석 (Analysis of the Fundamental Behaviors of the Middle Slab in a Double-Deck Tunnel for Design Guide Development)

  • 박희범;조영교;이영훈;김성민
    • 한국도로학회논문집
    • /
    • v.19 no.1
    • /
    • pp.63-72
    • /
    • 2017
  • PURPOSES : The purpose of this study is to investigate the fundamental behaviors such as stresses and deflections of the middle slab in a double-deck tunnel for the development of a middle slab design guide. METHODS : The middle slab has been divided into the following three different sections as according to its structural differences: the normal section, expansion joint section, and emergency passageway section. The normal section of middle slab represents the slab supported by brackets installed continuously along the longitudinal direction of tunnel lining. The expansion joint section refers to a discontinuity of middle slab due to the existence of a transverse expansion joint. The emergency passageway section has an empty rectangular space in the middle slab that acts as an exit in an emergency. The finite element analysis models of these three sections of middle slab have been developed to analyze their respective behaviors. RESULTS : The stresses and deflections of middle slab at the three different sections decrease as the slab thickness increases. The emergency passageway section yields the largest stresses and deflections, with the normal section yielding the smallest. CONCLUSIONS : The stress concentrations at the corners of the passageway rectangular space can be reduced by creating hunch areas at the corners. The stresses and deflections in the emergency passageway section can be significantly decreased by attaching beams under the middle slab in the passageway area.

플랫 플레이트 구조의 기둥.슬래브 접합부 연성에 관한 연구 (Ductility of Column-Slab eoint in R/C Flat Plate System)

  • 김형기;박복만
    • 한국콘크리트학회논문집
    • /
    • v.12 no.4
    • /
    • pp.113-119
    • /
    • 2000
  • The R/C flat plate system provides architectural flexibility, clear space, reduced building height, simple formwork, which consequently enhance constructibility. One of the serious problems in the flat plate system is brittle punching shear failure due to transfer of shear force and unbalanced moments in column-slab joint. Recently, the flat plate system accompanied with shear walls to resist the lateral loads is applied to high-rise buidings. Although the flat plate system is not considered in design as part of the lateral load-resisting system, it is required that this system keeps the ductile behavior for the lateral displacement of the building. However, it is unclear whether the column-slab joint possesses ductility enough to survive the lateral deformation. The objective of this paper is to investigate the major parameters that influence the ductility of R/C flat plate system by examining the existing experiments on column-slab joint. The effects of gravity load and shear reinforcement on the ductility of the flat plate system are presented.

트러서메쉬 보강 하프 슬래브의 구조적 거동에 관한 실험적 연구 (An Experimental Study on Structural Behavior of Half Slab Reinforced by Truss Mesh)

  • 고만영;김용부;박현수;정란
    • 한국콘크리트학회지
    • /
    • v.7 no.4
    • /
    • pp.119-128
    • /
    • 1995
  • 이 연구는 최근 건설공사에서의 인력 및 원가의 절감, 공기의 단축 등을 도모하기 위하여 도입되고 있는 하프슬래브의 실용화를 위한 구조거동을 알아보기 위한 실험적 연구이다. PC 패널의 두께, 트러스메쉬의 형사, 가력하중의 형태를 변수로 총 17개의 시험체를제작하여 PC 패널, 하프슬래브, 하프슬래브-벽체 접합부의 휨성능 실험을 하였다. 실험결과, 부방향 하중을 받는 PC 패널의 휨강도가 설계강도보다 작게 나타났으나 정방향 하중을 받는 PC판넬과 덧침콘크리트의 분리현상이 발견되지 않았으며 휨강도 또한 일체로 타설한 부재와 같은 휨내력을 발현하였다. 따라서, 본 연구에서는동바리를 2.0-2.5m간격으로 설치하고, PC판넬과 덧침콘크리트와의 접합면을 조면처리하고 청결을 유지하면 사용상 문제가 없는 것으로 판단되었다.

등가 전단 스프링 모델을 이용한 플로팅 슬래브궤도 연결부에서의 하중전달 특성 분석 (Investigation of Load Transfer Characteristics at Slab Joints In The Floating Slab Track by Equivalent Shear Spring Model)

  • 장승엽;안미경;최원일;박만호
    • 한국철도학회:학술대회논문집
    • /
    • /
    • pp.2838-2843
    • /
    • 2011
  • Recently, the floating slab track that can effectively mitigate the vibration and structure-borne noise is being discussed to be adopted. The floating slab track which is a track system isolated from the sub-structure by vibration isolators. Unsimilarly to conventional track and the slab deflection is large. Therefore, the running safety and ride comfort should be investigated. Especially at slab joint since the load cannot be transferred, the possibility that the dynamic behavior of track and train became unstable is high. Thus, in general dowel bar are often installed at slab joints. To determine the appropriate dowel ratio the load transfer characteristics should be investigated. In this study, dowel bar joint is modeled by equivalent shear spring and this model is verified by comparison with experimental results. Using the proven model, the load transfer efficiency and deflection at slab joint according to dowel ratio, and stiffness and spacing of vibration isolator were examined.

  • PDF

보-기둥 접합부의 전단거동에 대한 슬래브 및 횡구속 영향 (Transverse Concinement and Slab Effect on Shear Behavior of Beam-Column Connection)

  • 장극관;서대원;방세용
    • 한국콘크리트학회:학술대회논문집
    • /
    • /
    • pp.419-422
    • /
    • 1999
  • This study was intended to investigate the cyclic behavior of high strength concrete beam-column connection. Four assemblies were designed 2/3 scale beam-column-slab joint and tested. The obtained results are follows. 1) The transverse beams increase the shear resistance and ductility of joint, 2) The slab was contributed to increase of the flexural capacity of the beam, but was not contributed to increase the joint ductility under lateral loads.

  • PDF

탄소섬유와 L형강을 이용한 벽-슬래브 접합부의 보강성능 (Structural Performance of Seismic Resistance Capacity of Carbon Sheet-Angle Retrofitting Method in Wall-Slab Joint)

  • 노공기;박태원;박현수;정란
    • 한국콘크리트학회:학술대회논문집
    • /
    • /
    • pp.65-68
    • /
    • 2004
  • In the seismical capacity evaluation for RC structure wall-slab joint is very important factor. Because lateral load is resistance element and gravity load resistance element are acted mutually in the wall-slab joint. In this paper, to improve the seismic capacity of the wall-slab joint in the existing wall type apartments experiment which improve and retrofit a seismic capacity by unequal angle bracing and carbon sheet attachment are carried out. These methods are also economic and simple in mitigating seismic hazard, improve earthquake-resistance performance, and reduce risk level of building occupants. From the experimental results, the change of strength, degration of stiffness, and energy dissipation are evaluated. It can be concluded that these methods are effective in improving the seismic performance.

  • PDF

복층터널 중간슬래브 유지관리에 따른 응력분포 특성 분석 (Characteristics of Middle Slab Stresses in Double-Deck Tunnel During Maintenance)

  • 조영교;이영훈;박범근;김성민
    • 한국도로학회논문집
    • /
    • v.19 no.6
    • /
    • pp.47-56
    • /
    • 2017
  • PURPOSES : The purpose of this study is to investigate the stresses of the middle slab in a double-deck tunnel owing to the slab lift to replace the underlying elastic pads during maintenance work. METHODS : The middle slab was divided into three different sections: typical section, expansion joint section, and emergency passageway section. Finite element analysis models of these three sections of middle slab were developed, and the stress distribution and maximum stresses were obtained using the models when the middle slab was lifted to replace the underlying elastic pads. Various slab lifting methods were examined in this study such as one-, two-, and multiple-point lifts, distributed lifts, and one or both slab side edge lifts. RESULTS : When the slab side edge is lifted, the longitudinal stresses of the slab are almost the same as the principal stresses. This implies that the governing stresses are the longitudinal stresses. The maximum stresses with both-edge lifts are generally smaller than those with one-edge lifts at all three sections of middle slab. CONCLUSIONS : If the middle slab in a double-deck tunnel is lifted for maintenance, the slab should be lifted at multiple points along the longitudinal direction to reduce the tensile stresses.

슬래브 형식 프리캐스트 모듈러교량의 종방향 연결부 형상 결정에 관한 연구 (Study on the Shape of a Longitudinal Joint of the Slab-type Precast Modular Bridges)

  • 이상윤;송재준;김형열;이영호;이정미
    • 한국구조물진단유지관리공학회 논문집
    • /
    • v.16 no.5
    • /
    • pp.98-111
    • /
    • 2012
  • 본 연구에서는 급속시공을 위한 단지간의 슬래브 형식의 프리캐스트 모듈러교량의 종방향 연결부 상세를 제안하고자 한다. 슬래브 형식의 프리캐스트 모듈러교량은 횡방향으로 분절되어 제작되므로, 분절된 프리캐스트 모듈 사이에는 종방향의 연결부가 형성된다. 이에, 종방향 연결부의 형상과 제원을 결정하기 위해 전단키 개수, 폭, 높이, 경사각, 연결부 폭을 변수로 선정하여 해석적 연구와 실험적 연구를 함께 수행하였다. 결과 분석을 위해서 연결부에 초기 균열이 발생하는 균열하중에 대한 경향을 검토하였으며, 종방향 연결부의 효율성을 평가하기 위해 효율계수(efficiency factor)를 제안하였다. 해석 및 실험에서 얻어진 균열하중과 본 연구에서 제안된 효율계수를 이용하여 연결부의 형상 및 제원을 결정하였다.