• Title, Summary, Keyword: CWR

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A study of CWR on railway viaduct with sharp curves (철도고가교 급곡선부 레일장대화 방안연구)

  • 이상진;김기훈;신순호;이주헌
    • Proceedings of the KSR Conference
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    • pp.415-422
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    • 2000
  • The Seoul Subway Line 4 crossing downtown diagonally constructed in February 1980 and opened on October 11, 1983. The line 4 is thus able to link southern and northern parts of Seoul with the downtown as well as with the Seoul outskirts. More than 810,000 people use it everyday. Line 4 was constructed like Line 1,2,3 with ballast track system causing much maintenance cost gradually and espicially much public discontent due to wheel and rail contact noise by railway viaduct with sharp curves. CWR on railway viaduct with sharp curves, 180m$\leq$R$\leq$300m, hasn't been designed and constructed ever in domestic. Therefore in order to reduce noise and vibration caused by interaction between wheel and rail the possibility and the methods of CWR(Continuous Welded Rail) on railway viaduct with sharp curve less than R300 will lead it to the maintenance free system.

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The characteristics of the behaviour of plate girder bridges according to the boundary conditions. (경계조건에 따른 판형교 장대레일의 거동 특성)

  • Min Kyung-Ju;Jung Ue Ha;Kim Young-Kook
    • Proceedings of the KSR Conference
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    • pp.356-363
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    • 2003
  • The CWR of the plate girder bridges in non-ballast causes the additional axial force on the rail and the bearing due to the temperature axial force and the interaction between the CWR and bridges. This study shows the remarkable improvement of reducing the axial force of the CWR on the non-ballast bridge, compared to conventional methods. New method, which is differently designed in terms of longitudinal semi-rigid bearing, reduces the axial force on the bearing by making the girder act both directions. This method is applicable to most cases of bridges regardless of the restriction of length, and useful to reduce the abrasion and damage of the track material.

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A Study of Longitudinal Forces and Displacements in a Multi-Span Bridge Equipped with a CWR Track (장대레일이 설치된 교량에서의 축방향 변위 및 축력 변화 연구)

  • Lee, Joo-Heon;Huh, Young
    • Proceedings of the KSR Conference
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    • pp.442-449
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    • 1999
  • Due to temperature variations, considerable longitudinal rail forces and displacements may develop in continuous welded rail(CWR) track on long-span bridges or viaducts. Excessive relative displacements between sleepers and ballast bed may disturb the stable position of the track in the ballast which results in a lower frictional resistance. Generally, these problems are solved by installing rail expansion devices. However the application of expansion devices in high-speed tracks on existing bridges, as a means to prevent excessive longitudinal displacements and forces, is not attractive method due to comfort, safety and maintenance aspects. An alternative and very effective solution is possibly the use of so-called zero longitudinal restraint(ZLR) fastenings over some length of the track. The calculations, carried out in this respect, show a considerable reduction of track displacements, track forces, and the relative sleeper/ballast displacements. This reduction depends on the length over which these fastenings are installed. In this paper calculations of the longitudinal displacments and forces in a CWR track and substructure resulting from thermal, mechanical and kinematical loads were carried out using the FEM analysis program LUSAS

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Parametric Study on the Safety of CWR Track over High-Speed Railway Bridges (매개변수해석을 통한 고속전철교량상 장대레일궤도 안전성 검토)

  • 강재윤;김병석;김영진;박성용;조정래;최은석;진원종
    • Journal of the Korean Society for Railway
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    • v.5 no.1
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    • pp.1-9
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    • 2002
  • Where the track is continuously welded over the bridge, the longitudinal forces will be distributed interactively between the track and the sub-structure by the rail-bridge interaction mechanism. The ratio between the longitudinal forces transmitted in each elements depends on the magnitude of the ballast resistance and the stiffness of the sub-structures. In this paper, the main factors affect on the longitudinal rail force are discussed and the parametric study for the behavior of CWR(Continuous Welded Rail) track was executed. It is concluded that the horizontal ballast resistance and the stiffness of the bridge sub-structure are the significant parameters affecting the stability of the continuous welded rail track.

Analysis of the axial force in CWR connected with turnout by means of the field measurement (현장계측을 통한 교량상 분기기 축력 분석에 관한 연구)

  • Choi, Jin-Yu;Kim, In-Jae;Hwang, Sung-Ho;Yang, Shin-Chu
    • Proceedings of the KSR Conference
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    • pp.1289-1292
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    • 2006
  • The demand on a turnout layed on a bridge is rising owing to the increasing number of stations on the viaduct. And also the demand on a turnout with CWR is rising to upgrade running speed of the passing train. A CWR connected with turnout is subjected to additional axial force induced by the actions due to change in temperature, braking and starting force, and bending of the deck. But magnitude and distribution of the axial force in rails of turnout is not clear yet. So, in this study, a field measurement was conducted to know them. The strain gage method was adopted for field test. The FBG sensor for the strain measurement was used to ensure stability of test value and durability of gage for long term. It is expected that we can get data on the axial force in rail connected with turnout with respect to seasonal temperature change by the established field test system.

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Investigation of Thermal Stress of Continuous Welded Rail on High Speed Railway Bridge (경부고속철도 교량상 장대레일의 온도응력 계측 실험)

  • Kang, Jae-Yoon;Choi, Eun-Suk;Chin, Won-Jong;Lee, Jung-Woo;Kwark, Jong-Won;Kim, Byung-Suk
    • Proceedings of the KSR Conference
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    • pp.458-461
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    • 2007
  • Recently, the continuous welded rail(CWR) track has been used for less maintenance of the High-speed railway tracks. In case of CWR track, track buckling has always been an unpredictable event under the high compressive stress in rail. The behavior and stress state of CWR track is manily influenced by its thermal variations, and it is important to understand seasonal variations of rail temperature and stress to predict the track stability. This paper describes the in-site measurement for the rail temperature and rail stress, and the correlation between the rail temperature and stress was examined.

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Characteristics of the stress on CWR for railway bridge design (교량설계를 위한 장대레일 축력 특성 분석)

  • Choi, Il-Yoon;Cho, Hyun-Cheol;Choi, Jin-Yu;Yang, Sin-Chu
    • Proceedings of the KSR Conference
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    • pp.1395-1400
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    • 2007
  • Characteristics of the stress on Continuous Welded Rail(CWR) were investigated to apply to design procedure for railway bridge design. Actions due to change in temperature, braking/traction and bending of the deck were considered in this interaction analysis between CWR and bridge deck. The bridge parameters such as static arrangement of the deck and support stiffness were taken into consideration to examine the influence of the parameters on the additional rail stress. The final results of this study, which include the displacement as well as the stress will be presented in the form of the design chart in future.

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Type Suggestion and Parameter Study for Long-Span Bridge of High-Speed Railway without the REJ considering CWR Axial Force (장대레일 축력을 고려한 REJ 미적용 고속철도 특수교량 형식 제시 및 변수별 분석)

  • Lee, Jong-Soon;Joo, Hwan-Joong;Shin, Jai-Yeoul;Yoon, Sung-Sun;Park, Sun-Hee;Nam, Hyoung-Mo
    • Proceedings of the KSR Conference
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    • pp.1254-1261
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    • 2011
  • Application of long-span bridge, which is affected by parameters such as span length, shoe boundary condition, track property and stiffness of superstructure and substructure etc., can vary. Especially, by CWR aspects of the axial force, long-span high speed railway bridges are limited at type and span length. In this study, in terms of CWR axial force, the long-span high-speed railway bridges without REJ(Rail Expansion Joint) is to propose the bridge type. Various Parameters analysis performed for the proposed type(Arch bridge, Cable-stayed bridge).

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Parameter Study for Long-Span Bridge of High-Speed Railway considering CWR Axial Force (장대레일 축력을 고려한 고속철도 특수교량의 변수별 분석)

  • Lee, Jong-Soon;Cho, Soo-Ik;Park, Man-Ho;Joo, Hwan-Joong;Nam, Hyoung-Mo
    • Proceedings of the KSR Conference
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    • pp.1452-1459
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    • 2010
  • Application of long-span bridge, which is affected by parameters such as span length, shoe boundary condition, track property and stiffness of superstructure and substructure etc., can vary. Especially, by CWR aspects of the axial force, that can be less constraints of construction depending on whether the application of rail expansion joint(REJ), which has disadvantaged in terms of maintenance. In this study, it was performed parameter study for multiple variables (shaft length, the upper and lower cross-section characteristics, track characteristics, etc.) in terms of CWR aspects. Structure-rail interaction analysis was applied to the typical simple span PSC Box and 3 span continuous bridge Extradosed Bridge(50m+80m+50m) excluding REJ. If you set the boundary e of variables for long-span railway bridge excluding REJ through the this study, when designing future is expected to be able to useful.

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Buckling Probability Evaluation Framework of CWR Tracks (장대레일 궤도의 좌굴확률평가 시스템)

  • Bae, Hyun-Ung;Han, Seung-Ryong;Choi, Jin-Yu;Lim, Nam-Hyoung
    • Proceedings of the KSR Conference
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    • pp.305-309
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    • 2010
  • The buckling behavior of CWR tracks is affected by the various parameters such as stiffness and geometry of track panel, ballast resistance, rail temperature, initial imperfection, and wheel load. Until now, CWR tracks were managed by the dichotomous logic (deterministic approach) despite these influence factors are having the nature of random variables. So, the design method and existing management process to prevent the track buckling can be very non-economic since the value of these influence factors to calculate the track buckling strength are selected by considering the worst track condition. In this study, buckling probability evaluation process is proposed which is based on the reliability index, AFOSM method, and limit state equation.

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