• Title/Summary/Keyword: Concrete Track

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A Study on Behavior of Concrete Slab Track subjected to High Speed Train Loads (고속열차하중을 받는 슬래브궤도의 동적거동에 관한 연구)

  • 조병완
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.04a
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    • pp.485-492
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    • 2000
  • In the rail facilities the rail track consists of rail tie fastening accessories and bed,. The rail track is largely divided into Ballast Bed Track(BBT) and Concrete Bed Track(CBT) according to the type of bed. In this thesis among Concrete Bed Track slab track which is used for the Japanese high speed railway is a target of this study. Dynamic analysis by using finite element method are performed. where moving rain load is periodic function. Then through parametric study some conclusions are obtained as follow. Cement Asphalt Mortar(CAM) affects contrary mechanical behavior to rail and slab greatly. Therefore change of CAM spring coefficient should be handled with care, For slab thickness thin slab is more profitable to reduction of vibration of rail than thick one but mechanical capacity of slab is deteriorated, Improved structural type is proposed then structural analysis is performed for this one. This type is effective to reduction of vibration of railway system.

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Suggestion for Train Vibration Equations based on Change in Track System (궤도구조 변경에 따른 열차 진동 추정식 제안)

  • 김응록;박연수;강성후;박선준;김흥기
    • Journal of the Korean Society for Railway
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    • v.5 no.1
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    • pp.48-54
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    • 2002
  • This research estimated decreased vibration level as quantitative according to change of track system on Seoul Subway Line No. 1 from existing ballasted track system(Pandrol type clip) to concrete track system(Youbgdan type isolation rubber clip). Following change to concrete system, vibration level at tunnel floor decreased between 4-8dB(V). Vibration equations suggested in this paper consider the velocity of train and can estimate quantitative vibration response. These are divided by ultimate limit state($\beta$=0), serviceability limit state($\beta$=1.28) and safety state($\beta$=3), respectively. The reliability index, $\beta$=0, means 50% data line obtained by least squares best-fit line. The reliability index $\beta$=1.28 and 3 represent boundaries below 90% and 99.9% respectively.

A Method for the Analysis of Train/Slab-Track Interaction on Settled Roadbed (슬래브궤도 노반침하구간 차량/궤도 상호작용 해석기법 개발)

  • Yang, Sin-Chu;Hong, Chul-Kee
    • Journal of the Korean Society for Railway
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    • v.10 no.3 s.40
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    • pp.296-305
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    • 2007
  • A numerical method for the analysis of train/slab-track interaction on the settled roadbed is developed based on the already developed analysis method of train/ballast-track interaction. The concrete slabs composed of the upper track concrete layer and the lower hydraulic bonded layer are modelled by a equivalent beam. The supporting stiffness of roadbed is evaluated with the modified boussinesq method suggested by Eisenmann. The track irregularity and the gap between slab and roadbed induced by settlement of roadbed are calculated by the effective method newly presented in this study. The validation of the developed method is investigated by a numerical example. The effects of train speed on train and slab track on the settled roadbed with sinusoidal shape of wave length 20m and amplitude 20mm are reviewed.

Dynamic response of steel-concrete composite bridges loaded by high-speed train

  • Podworna, Monika
    • Structural Engineering and Mechanics
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    • v.62 no.2
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    • pp.179-196
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    • 2017
  • The paper focuses on dynamic analyses of a series of simply-supported symmetric composite steel-concrete bridges loaded by an ICE-3 train moving at high speeds up to 300 km/h. The series includes five bridges with span lengths ranging from 15 m to 27 m, with repeatable geometry of the superstructures. The objects, designed according to Polish standards valid from 1980s to 2010, are modelled on the bridges serviced on the Central Main Line in Poland since 1980s. The advanced, two-dimensional, physically nonlinear model of the bridge-track structure-high-speed train system takes into account unilateral nonlinear wheel-rail contact according to Hertz's theory and random vertical track irregularities equal for both rails. The analyses are focused on the influence of random track irregularities on dynamic response of composite steel-concrete bridges loaded by an ICE-3 train. It has been pointed out that certain restrictions on the train speed and on vertical track irregularities should be imposed.

A Study of Frost Penetration Depth and Frost Heaving in Railway Concrete Track (콘크리트 궤도의 동결깊이 및 동상량 측정 연구)

  • Lee, Daeyoung;Kim, Youngchin
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.1
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    • pp.35-41
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    • 2014
  • Many infra suructure such as road, railway, building and utility foundations have been damaged by the repeated freezing and thawing of the soil during winter and spring every year in seasonal frost region. The frost penetration depth is most important factor in the design of structure such as road, railway and building in seasonal frost region. This paper presents the results of calculation of frost penetration depth and frost heaving in concrete track for railway construction. Model concrete track were installed near the railway track in Gangwon, Gyeonggi, Choongbuk province and frost penetration depth were measured using methylene blue frost penetration depth gauge. Model concrete track in Cheolwon, frost heaving of concrete track were also evaluated. The measure of maximum frost penetration depth and frost heaving can be applied to design railway track for cold region in Korea.

Research directions for maintenance criteria in Slab Track (콘크리트궤도 유지보수기준 정립을 위한 연구방향)

  • Eom, Jong-Woo;Lee, Myung-Suk;Kwon, Jin-Soo;Kim, Soo-Jung
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.979-987
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    • 2011
  • The Ballast Track has been widely applied in traditionally due to low initial cost and abundant elastic property. But the disadvantages of Ballast track are; labor-intensive and costly maintenance, weak in high-speed and heavy axial load, in additionally need wide cross section of tunnel and massive substructure in viaduct. Therefore, recent applications tend to more and more towards slab track such as Gyeungbu high speed rail and existing line. The slab track increased the stability, resistance and durability of track, and save maintenance cost compare to the Ballast Track. But the slab track have weakness of track elongation by sub-ballast differential settlement and that threat safety of train operation. Therefor the slab track need to prevent cracks in concrete ballast for insure the durability of slab track. In this paper, review main items and its expected effects of the slab track maintenance standards that control sub-ballast settlement and concrete ballast cracks.

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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 Dynamic Behavior Evaluation of the Curved Rail according to Lateral Spring Stiffness of Track System (궤도시스템의 횡탄성에 따른 곡선부 레일의 동적거동평가)

  • Kim, Bag-Jin;Choi, Jung-Youl;Chun, Dae-Sung;Eom, Mac;Kang, Yun-Suk;Park, Yong-Gul
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.517-528
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    • 2007
  • Domestic or international existing researches regarding rail damage factors are focused on laying, vehicle conditions, driving speed and driving habits and overlook characteristics of track structure (elasticity, maintenance etc). Also in ballast track, as there is no special lateral spring stiffness of track also called as ballast lateral resistance in concrete track, generally, existing study shows concrete track has 2 time shorter life cycle for rail replacement than ballast track due to abrasion. As a result of domestic concrete track design and operation performance review, concrete track elasticity is lower than track elasticity of ballast track resulting higher damage on rail and tracks. Generally, concrete track has advantage in track elasticity adjustment than ballast track and in case of Europe, in concrete track design, it is recommended to have same or higher performance range of vertical elastic stiffness of ballast track but domestically or internationally review on lateral spring stiffness of track is very minimal. Therefore, through analysis of service line track on site measurement and analysis on performance of maintenance, in this research, dynamic characteristic behaviors of commonly used ballast and concrete track are studied to infer elasticity of service line track and experimentally prove effects of track lateral spring stiffness that influence curved rail damage as well as correlation between track elasticity by track system and rail damage to propose importance of appropriate elastic stiffness level for concrete and ballast track.

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Evaluation of Train Running Safety for Direct Fixation Concrete Track on Light Rapid Transit (경전철 직결식 콘크리트 궤도구조의 열차주행안전성 평가)

  • Choi, Jung-Youl;Kim, Jun-Hyung;Chung, Jee-Seung;Lee, Sun-Gil
    • Journal of the Korean Society of Safety
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    • v.32 no.5
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    • pp.41-46
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    • 2017
  • The coefficient of derailment and the rate of wheel load reduction were used as the index of train running safety that was directly affected the train derailment safety. In aspects of track, the train running safety depends on the complex interaction between wheel and rail, and the track-vehicle conditions (i.e., the curvature, cant, track system, vehicle speed and the operation conditions, etc). In this study, the relationship between the train running safety and the track curvature and vehicle speed for direct fixation concrete tracks currently employed in Korean light rapid transit was assessed by performing field tests using actual vehicles running along the service lines. The measured dynamic wheel load, lateral wheel load and lateral displacement of rail head were measured for same train running on four tested tracks under real conditions, which included curved and tangent tracks placed on the tunnel and bridge, thus increasing the train speed by approximately maximum design speed of each test site. Therefore, the measured dynamic track response was applied to the running safety analysis in order to evaluate the coefficient of derailment, the rate of wheel load reduction and the track gauge widening at each test site, and compare with the corresponding Korean train running safety standard. As the results, the lateral track response of direct fixation concrete track appeared to increase with the decreased track curvature; therefore, it was inferred that the track curvature directly affected the train running safety.

The Effect of Pile Distallation on the Reduction of Cumulative Plastic Settlement (말뚝 설치를 통한 콘크리트궤도의 누적소성침하 감소 효과)

  • Lee, Su-Hyung;Lee, Il-Wha;Lee, Sung-Jin;Kim, Dae-Sang
    • Journal of the Korean Geotechnical Society
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    • v.24 no.5
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    • pp.129-137
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    • 2008
  • An active application of concrete track is being expected far the future constructions of Korean railroad. In comparison with the existing ballasted tract, a concrete track is very susceptible for the settlement, since its rehabilitation requires much time and cost. When a concrete track is constructed on fine-grained subgrade soil, excessive cumulative plastic settlements due to repetitive train road may occur. In this case, the settlement of the concrete track may be effectively reduced by installing a small number of small-diameter piles beneath the track. This paper presents the effect of pile installation on the reduction of cumulative plastic settlement of concrete track. A method combining experiential equation and numerical method is proposed. Using an existing experiential equation and the estimated earth pressure distribution, the cumulative plastic strain was calculated. From the results, it is verified that the effects of the pile installation is significant to effectively reduce the cumulative plastic settlement of concrete track. The reduction effects of the cumulative plastic settlement according to the pile number and pile arrangement are presented.