• Title, Summary, Keyword: 콘크리트궤도

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Analysis of Shear Behavior of Shear Key for Concrete Track on Railway Bridge Considering Construction Joint (타설 경계면을 고려한 철도교 콘크리트궤도 전단키의 전단 거동 해석)

  • Lee, Seong-Cheol;Kang, Yun-Suk;Jang, Seung Yup
    • Journal of the Korean Society for Railway
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    • v.19 no.3
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    • pp.341-350
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    • 2016
  • Concrete track on railway bridges should be designed to effectively respond to the movement of the superstructure of the bridge. In the design procedure, shear keys are generally placed on the protection concrete layer (PCL) before casting the concrete track so the shear force due to slip between the concrete track and the bridge super-structure can be transferred. In this paper, a nonlinear structural analysis procedure that considers the construction joint has been developed to predict the shear behavior of a shear key. With the developed analysis procedure, it was possible to predict the shear force-shear slip response at the construction joint in a shear key by considering the friction of concrete surface and the dowel action of the rebars. The analysis results showed good agreement with the test results for 4 specimens.

A Study on Evaluation of Vibration Reduction Effect of Concrete tracks (콘크리트 궤도 유형별 진동성능평가에 대한 연구)

  • Yang, Shin-Chu;Kim, Eun;Kang, Yun-Suk;Um, Ju-Hwan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.911-916
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    • 2002
  • One of important roles of concrete track is to reduce vibration transmitting to subgrade. In this paper, a numerical method for evaluating the effects of vibration reduction of concrete track is presented. Using the method, high frequency dynamic analyses and track-tunnel-soil interaction analyses are carried out for three types of concrete track in order to investigate the vibration reduction effects compared with normal ballast track.

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Experimental Study on Applying a Transition Track System to Improve Track Serviceability in Railway Bridge Deck Ends (철도교량 단부 궤도의 사용성 향상을 위한 횡단궤도시스템 적용에 관한 실험적 연구)

  • Lim, Jongil;Song, Sunok;Choi, Jungyoul;Park, Yonggul
    • Journal of the Korean Society for Railway
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    • v.16 no.3
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    • pp.207-216
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    • 2013
  • The components of concrete track (rail and rail fastening system) in railway bridge deck ends are damaged and deteriorated by track-bridge interaction forces such as uplift forces and compression forces owing to their structural flexural characteristics (bridge end rotation). This had led to demand for alternatives to improve structural safety and serviceability. In this study, the authors aim to develop a transition track to enhance the long term workability and durability of concrete track components in railway bridge deck ends and thereby improve the performance of concrete track. A time-history analysis and a three-dimensional finite element method analysis were performed to consider the train speed and the effect of multiple train loads and the results were compared with the performance requirements and German standard for transition track. Furthermore, two specimens, a normal concrete track and a transition track, were fabricated to evaluate the effects of application of the developed transition track, and static tests were conducted. From the results, the track-bridge interaction force acting on the track components (rail displacement, rail stress, and clip stress) of the railway bridge deck end were significantly reduced with use of the developed transition track compared with the non-transition track specimen.

A Study on Relationship between Track Impact Factor and Track Support Stiffness of Turnout System on Urban Transit (도시철도 분기기 궤도구조의 궤도지지강성과 궤도충격계수의 상관관계에 관한 연구)

  • Choi, Jung-Youl;Park, Jong-Yoon;Lee, Kyu-Yong;Chung, Jee Seung
    • The Journal of the Convergence on Culture Technology
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    • v.6 no.2
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    • pp.461-466
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    • 2020
  • In this study, the relationship between the track support stiffness and the track impact factor for a sleeper floating track and a turnout system with wood ties currently employed in Korean urban transit was assessed by performing field tests using actual vehicles running along the service lines. Field tests were performed on four track systems (i.e., sleeper floating track, and point, lead and crossing sections of turnout system). The theoretically designed track impact factor and track support stiffness were compared with the corresponding track impact factor and track support stiffness measured through field tests for the target tracks on the service line. The track impact factor for the service line appeared to increase with the deviation of track support stiffness according to vehicle driving direction; therefore, it was inferred that the deviation of track support stiffness between each track section directly affected the track impact factor.

Characteristics of Roadbed Behaviors of Concrete Track for High-Speed Railway (고속철도 콘크리트궤도용 흙노반의 거동 특성)

  • Lee Il-Wha;Lee Su-Hyung;Kang Yun-Suk
    • Journal of the Korean Society for Railway
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    • v.9 no.3
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    • pp.298-304
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    • 2006
  • An active application of concrete track is being expected for the future constructions of Korean railroad. For the successful concrete track construction and design in earthwork areas, the roadbed behavior should be reasonably estimated using the proper analysis method. In this paper, behaviors of concrete track on the reinforced roadbed constructed with the standard stiffness and depth were estimated thorough numerical analyses and field measurements. A three dimensional finite difference method was employed to model the concrete tracks and subground. The settlement and vertical pressures caused by train load were estimated by the numerical method and compared with the field measurement results. The bearing characteristics of roadbed were presented and the proper method for the analysis of concrete track was proposed.

Assessment of Train Running Safety, Ride Comfort and Track Serviceability at Transition between Floating Slab Track and Conventional Concrete Track (플로팅 슬래브궤도와 일반 콘크리트궤도 접속구간에서의 열차 주행 안전, 승차감 및 궤도 사용성 평가)

  • Jang, Seung-Yup;Yang, Sin-Chu
    • Journal of the Korean Society for Railway
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    • v.15 no.1
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    • pp.48-61
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    • 2012
  • It is of great importance to assure the running safety, ride comfort and serviceability in designing the floating slab track for mitigation of train-induced vibration. In this paper, for this, analyzed are the system requirements for the running safety, ride comfort and serviceability, and then, the behavior of train and track at the floating slab track including the transition zone to the conventional concrete slab track according to several main design variables such as system natural frequency, arrangement of spring at transition, spacing of spring isolators, damping ratio and train speed, using the dynamic analysis technique considering the train-track interaction. The results of this study demonstrate that the discontinuity of the support stiffness at the transition results in a drastic increase of the dynamic response such as wheel-rail interaction force, rail bending stress and rail uplift force. Hence, it is efficient to decrease the spacing of springs or to increase the spring constants at the transition to obtain the running safety and serviceability. On the other hand, the vehicle body acceleration as a measure of ride comfort is little affected by the discontinuity of the stiffness at the transition, but by the system tuning frequency; thus, to obtain the ride comfort, it is of great significance to select the appropriate system tuning frequency. In addition, the effects of damping ratio, spacing of springs and train speed on the dynamic behavior of the system have been discussed.

Deformation and Stress Distribution of Discontinuous Precast Concrete Track Slab : II. Stress Distribution (불연속 프리캐스트 콘크리트궤도 슬래브의 변형과 응력 분포 : II. 응력 분포)

  • Lee, Dong Hoon;Kim, Ki Hyun;Jang, Seung Yup;Zi, Goangseup
    • Journal of the Korean Society for Railway
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    • v.20 no.5
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    • pp.637-648
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    • 2017
  • In this paper, the effects of initial built-in deformation and temperature deformation on the stress distribution of discontinuous precast concrete track slab under train load were examined. According to the results, when train load is put on a precast concrete slab with initial built-in deformation and deformation due to temperature gradient, the maximum tensile stresses develop at the upper side of slab in the slab center, edge center and corner of shear pocket; the stress distribution is different from that of the case under train load only. Therefore, to accurately predict the actual weak points and failure modes, one should calculate the stress under train load considering the initial built-in and temperature deformation of the slab.

Track-Structure Interaction Analysis of Fast Hardening Track on Railway Bridge Considering Effect of Anchor and Friction (앵커와 마찰의 영향을 고려한 교량상 급속경화궤도의 궤도-교량 상호작용해석)

  • Cho, Sang-Hyeon;Lee, Il-Wha;Chung, Won-Seok;Lee, Hee-Young;Lee, Kyoung-Chan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.1
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    • pp.53-61
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    • 2018
  • Ballast track requires constant maintenance work due to progress of track irregularity. Fast Hardening Track(FHT) has been developed to reduce the maintenance effort done by injecting fast hardening mortar in aged ballast to convert slab track. For the application of FHT to a railway bridge, post-installed anchors should be placed at center of the track segment to fix it on bridge. This paper presents track-bridge interaction analysis results with FHT considering stiffness and strength of post-installed anchor, age of FHT concrete and friction between FHT and bridge deck surface. Based on the analysis results, this study suggests when is good to install the anchors and allow normal operation of passing train.

Settlement of Embankment and Foundation for Concrete Track of Gyungbu High Speed Railroad (경부고속철도 콘크리트궤도 토공 및 원지반 침하 (I))

  • Yang, Shin-Chu;Moon, Jae-Suk;Lee, Hyun-Jung;Kang, Dae-Woong;Kim, Dae-Sang
    • Journal of the Korean Society for Railway
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    • v.9 no.6
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    • pp.644-651
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    • 2006
  • An application of concrete track is being actively processed for the construction of Korean railroad. The concrete track has an advantage to decrease the maintenance ire, but is very difficult system to maintain after earthwork settlement occurred. Therefore, the management and control of embankment and foundation settlement is very important for the successful concrete track construction. We expect that the main part of the settlement of the concrete track is the one of embankment and foundation supporting it. Settlements vulnerable to the concrete track among the causes of lots of settlements are primary consolidation and secondary compression settlement of foundation, creep settlement of embankment, settlement caused by train load, and unequal settlement resulting from the difference of embankment material and construction process. This paper investigated the settlement causes to make badly effects on the concrete track and also evaluated the settlement with field tests and numerical analysis.

Application of the Absorbing Boundary Condition in Moving Force Analysis of Asphalt Concrete Track (흡수경계조건의 아스팔트 콘크리트 궤도 동적 해석에의 적용)

  • Lee, Seonghyeok;Chung, Keunyoung;Jung, Wooyoung
    • Journal of the Korean Society for Railway
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    • v.19 no.1
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    • pp.54-66
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    • 2016
  • In this study, the absorbing boundary condition was adopted to prevent elastic wave propagation due to abrupt load condition changes in moving force analysis. It was proven to be effective in reducing inappropriate noise components. Furthermore, to verify whether fixed point excitation in a laboratory test can simulate train movement effectively, the results of dynamic analysis for fixed point excitation and moving force conditions were analyzed. The dynamic stability of an asphalt track structure under a KTX train condition was also studied. Additionally, the dynamic safety of asphalt tracks was verified by comparing the results of a moving force analysis under a KTX train load and a quasi-static analysis under the design standard Korean train load.