• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1659-1663
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• 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.

• 대한토목학회논문집
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• 제35권5호
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• pp.1179-1189
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• 2015

장대레일을 적용한 교량상 콘크리트 궤도는 온도하중 및 시제동 하중에 의하여 종방향 상호작용력이 크게 발생하며, 이를 해소하기 위하여 활동체결장치 또는 저체결력 체결장치와 같은 특수체결장치를 적용하거나 레일신축이음장치를 설치하여야 한다. 슬라이딩 슬래브 궤도는 교량과 궤도 슬래브 사이에 슬라이드층을 두어 상호작용을 저감시킬 수 있는 것으로 알려져 있다. 이 연구에서는 슬라이딩 궤도와 일반 콘크리트 궤도를 적용한 교량에 대하여 상호작용 해석 결과를 제공한다. 해석 결과 슬라이딩 궤도를 적용함으로써 장대레일에 발생하는 부가 축력을 현저히 저감시킬 수 있는 것으로 밝혀졌으며, 그 차이는 장경간 및 연속교에서 더욱 큰 것으로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.463-470
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• 1999

In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effect of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.955-960
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• 2004

In this study, three dimensional FE analysis of concrete slab track has been performed in order to develop the realistic design of precast concrete slab track. The precast slab track system including the precast concrete slab panel and the grout layer is modeled using the three dimensional solid element with crack softening effect. The input load is computed from the one dimensional beam element model constituting the rail and several discrete springs. To investigate the effect of the longitudinal connection of slab panels, two different systems-continuous and discrete systems - are modeled. The analytical results show that the stresses of both the slab panel and the grout layer are in the range of linear elastic, and, at the interface between two adjacent panels, the primary stresses of the grout layer of the discrete system are higher than those of the continuous system. However, The overall stress levels of the grout layer are very low relative to the strength of th grout.

• Structural Engineering and Mechanics
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• 제78권2호
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• pp.163-174
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• 2021

Track-bridge interaction has become an essential part in the design of bridges and rails in terms of modern railways. As a unique ballastless slab track, the longitudinal continuous slab track (LCST) or referred to as the China railway track system Type-II (CRTS II) slab track, demonstrates a complex force mechanism. Therefore, a comprehensive track-bridge interaction study between multi-span simply supported beam bridges and the LCST is presented in this work. In specific, we have developed an integrated finite element model to investigate the overall interaction effects of the LCST-bridge system subjected to the actions of temperature changes, traffic loads, and braking forces. In that place, the deformation patterns of the track and bridge, and the distributions of longitudinal forces and the interfacial shear stress are studied. Our results show that the additional rail stress has been reduced under various loads and the rail's deformation has become much smoother after the transition of the two continuous structural layers of the LCST. However, the influence of the temperature difference of bridges is significant and cannot be ignored as this action can bend the bridge like the traffic load. The uniform temperature change causes the tensile stress of the concrete track structure and further induce cracks in them. Additionally, the influences of the friction coefficient of the sliding layer and the interfacial bond characteristics on the LCST's performance are discussed. The systematic study presented in this work may have some potential impacts on the understanding of the overall mechanical behavior of the LCST-bridge system.

• Structural Engineering and Mechanics
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• 제63권6호
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• pp.713-723
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• 2017

As a new type of ballastless track, longitudinal continuous slab track (CST) has been widely used in China. It can partly isolate the interaction between the ballastless track and the bridge and thus the rail expansion device would be unnecessary. Compared with the traditional track, CST is composed of multi layers of continuous structures and various connecting components. In order to investigate the performance of CST on a long-span bridge, the spatial finite element model considering each layer of the CST structure, connecting components, bridge, and subgrade is established and verified according to the theory of beam-rail interaction. The nonlinear resistance of materials between multilayer track structures is measured by experiments, while the temperature gradients of the bridge and CST are based on the long-term measured data. This study compares the force distribution rules of ballasted track and CST as respectively applied to a long span bridge. The effects of different damage conditions on CST structures are also discussed. The results show that the additional rail stress is small and the CST structure has a high safety factor under the measured temperature load. The rail expansion device can be cancelled when CST is adopted on the long span bridge. Beam end rotation caused by temperature gradient and vertical load will have a significant effect on the rail stress of CST. The additional flexure stress should be considered with the additional expansion stress simultaneously when the rail stress of CST requires to be checked. Both the maximum sliding friction coefficient of sliding layer and cracking condition of concrete plate should be considered to decide the arrangement of connecting components and the ultimate expansion span of the bridge when adopting CST.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.561-566
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• 2003

In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under floating slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effects of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.

• 한국전산구조공학회논문집
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• 제29권2호
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• pp.169-177
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• 2016

슬라이딩 궤도는 콘크리트 궤도와 교량 바닥판 사이에 저마찰 슬라이드층을 두어 레일신축이음장치와 같은 특수 장치를 적용하지 않고도 궤도-교량 상호작용 효과를 효과적으로 저감시킬 수 있는 새로운 궤도 시스템으로 개발되고 있다. 이 논문에서는 장경간 교량에 슬라이딩 궤도와 레일신축이음장치를 각각 적용한 경우에 대하여 궤도-교량 상호작용해석을 수행하고 그 결과를 비교 검토하였다. 대상교량은 상호작용 효과를 극대화하기 위하여 9경간 연속 PSC교와 2경간 연속 강합성교를 포함하며, 총 연장 1,205m, 최대 고정지점간 거리 825m인 장경간 교량을 선정하였다. 해석결과 슬라이딩 궤도는 레일신축이음장치를 적용한 경우보다 레일 부가 축력이 더 작은 것은 물론, 지점부에 재하되는 수평 반력 또한 작게 나타나 궤도-교량 상호작용 저감 효과가 뛰어난 것으로 확인되었다. 반면 슬라이딩 궤도는 온도하중에 의해 높은 슬래브 축력이 발생되므로, 궤도 설계 시 슬래브 축력에 대한 단면 설계에 주의를 기울일 필요가 있다.

• 한국철도학회논문집
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• 제12권1호
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• pp.95-103
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• 2009

교대나 교각 위 교량 슬래브 단부의 변형은 궤도 틀림이나 유지보수의 주요 원인이 되고 있으며, 특히 콘크리트 슬래브궤도가 설치되는 경우에는 궤도구조의 강성과 교량 슬래브와의 일체 성으로 레일 및 지지구조의 사용성에 심각한 영향을 미치는 변형과 추가하중이 발생하게 된다. 이번 연구에서는 교량 슬래브 단부 변형으로 인해 발생하는 궤도구조의 사용성에 영향을 미치는 인자를 파악하고 매개변수 해석을 통해 변수 별 영향 정도를 파악하였다. 연구 결과 단경간교 보다 연속교가 레일 지지점 하중 감소에 유리하고, 마지막 레일 지지점과 교량받침 사이 간격, 교량받침 강성, 체결구 강성이 사용성에 큰 영향을 미치는 것으로 분석되었다.

• 한국안전학회지
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• 제32권4호
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• pp.28-33
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• 2017

A sharp curved ballasted track on earthwork that was connected with a direct fixation slab track on steel box railway bridges have been deformed and damaged despite the frequently maintenance by a restoring force of sharp curved rail and track-bridge interaction forces such as axial forces and longitudinal displacement of continuous welded rail(CWR) owing to their structural characteristics, calling for alternatives to improve the structural safety and track irregularity. In this study, the authors aim to prove a cause of deformation for the sharp curved ballasted tracks to enhance the structural safety and track irregularity of ballasted track in service. A track-bridge interaction analysis and a finite-element method analysis for the sharp curved ballasted track were performed to consider the axial force and longitudinal displacement of CWR, the temperature and the effect of restoring force of sharp curved rail. From the results, the deformation of the sharp curved ballasted track with adjusted sleeper spacing from 833mm to 590mm were significantly reduced.