• Title, Summary, Keyword: Concrete Slab Track

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A Parametric Study on the Serviceability of Concrete Slab Track on Railway Bridges (철도교 콘크리트 슬래브궤도의 사용성에 관한 매개변수 영향 연구)

  • Park, Hong-Kee;Jang, Seung-Yup;Yang, Sin-Chu;Park, Yong-Gul
    • Journal of the Korean Society for Railway
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    • v.12 no.1
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    • pp.95-103
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    • 2009
  • Deformations of bridge deck ends on abutments and piers bring about severe problems in track geometry and require maintenance work. In case of concrete slab track, more severe deformation and additional forces on rail and rail supports can be induced by bridge deck deformation, which affect the serviceability of track structure since concrete slab track is much stiffer than ballasted track and the behavior of track structure is integrated with that of bridge deck. In this study, the design variables affecting the serviceability of track structure are selected and the influence level is estimated by a parametric study. As a result, it is found that continuous span is advantageous than simply supported span and the stiffness of bridge bearing and rail fastener as well as the distance between last rail support and bridge bearing are most important parameters.

Design and modelling of pre-cast steel-concrete composites for resilient railway track slabs

  • Mirza, Olivia;Kaewunruen, Sakdirat;Kwok, Kenny;Griffin, Dane W.P.
    • Steel and Composite Structures
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    • v.22 no.3
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    • pp.537-565
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    • 2016
  • Australian railway networks possess a large amount of aging timber components and need to replace them in excess of 280 thousands $m^3$ per year. The relatively high turnover of timber sleepers (crossties in a plain track), bearers (skeleton ties in a turnout), and transoms (bridge cross beams) is responsible for producing greenhouse gas emissions 6 times greater than an equivalent reinforced concrete counterparts. This paper presents an innovative solution for the replacement of aging timber transoms installed on existing railway bridges along with the incorporation of a continuous walkway platform, which is proven to provide environmental, safety and financial benefits. Recent developments for alternative composite materials to replace timber components in railway infrastructure construction and maintenance demonstrate some compatibility issues with track stiffness as well as structural and geometrical track systems. Structural concrete are generally used for new railway bridges where the comparatively thicker and heavier fixed slab track systems can be accommodated. This study firstly demonstrates a novel and resilient alterative by incorporating steel-concrete composite slab theory and combines the capabilities of being precast and modulated, in order to reduce the depth, weight and required installation time relative to conventional concrete direct-fixation track slab systems. Clear benefits of the new steel-concrete composites are the maintainability and constructability, especially for existing railway bridges (or brown fields). Critical considerations in the design and finite element modelling for performance benchmarking of composite structures and their failure modes are highlighted in this paper, altogether with risks, compatibilities and compliances.

The Influence of Frequency on Wayside Transmitter of ATP System upon Reinforcing Bars in Concrete Slab Track (콘크리트 슬래브궤도에서 ATP시스템 지상자의 주파수가 철근에 미치는 영향)

  • Kim, Min-Seok;Lee, Jong-Woo;Ko, Jun-Seog
    • Proceedings of the KSR Conference
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    • pp.691-706
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    • 2008
  • ATP(Automatic Train Protection) system in railway signaling system is the important one grasping the position and velocity of a train. The wayside transmitter of ATP system is installed between rails. In concrete slab track, the signal current using wayside transmitter of ATP system is influenced by reinforcing bars. The magnetic coupling between reinforcing bars and wayside transmitter of ATP system as a filter makes an input current distorted. So, it makes an alternating current signal with a desirable size not transmit to on-board system of a train. Way to decrease the distortion of an input current signal frequency is to avoid maximum induction current frequency. And the induction phenomenon between reinforcing bars insulated and wayside transmitter of ATP system does not occur. In this paper, we represent the model about wayside transmitter of ATP system and reinforcing bars on the concrete slab tracks, and calculated the parameters demanded for the model. Also, we demonstrated it through the Maxwell program. Furthermore, we calculated impedance on wayside transmitter used in KVB system and ERTMS/ETCS system which are a kind of ATP system, frequency response of induction current, using the Matlab, and demonstrated the validity of it, using the PSpice program.

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Unsupported Sleepers in Transition Zone between Concrete Slab Track and Ballasted Track : Phenomena and Its Countermeasures (고속철도 콘크리트궤도-자갈도상궤도 완충구간의 뜬침목 발생 현상과 대책)

  • Jang, Seung-Yup;Im, Oh-Jin;Yang, Sin-Chu
    • Proceedings of the KSR Conference
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    • pp.1126-1131
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    • 2007
  • In 1st Phase Kyeong-Bu High-Speed Line, to lessen the impact in the transition zone between concrete slab track(in tunnel) and ballasted track(on embankment), the ballast bonding method has been adopted. However, in this area, in the beginning of the operation, unsupported sleepers are found, and the track deterioration and damage of concrete sleepers have occurred. In this paper, the status and causes of unsupported sleepers are discussed and several repair measures are proposed.

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Appropriateness Evaluation of Reinforced Subgrade beneath Concrete Track through Numerical Analysis (수치해석을 통한 콘크리트궤도 하부 강화노반의 적정성 검토)

  • Lee Su-Hyung
    • Proceedings of the KSR Conference
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    • pp.680-685
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    • 2005
  • An active application of concrete track is being expected for the future constructions of Korean railroad. For the successful concrete track construction in earthwork areas, proper reinforced subgrades, which effectively distribute train loads to subground, should be installed. In this paper, behaviors of concrete track on the reinforced subgrade with the standard stiffness and depth were investigated through numerical analyses. The appropriateness of the reinforced subgade was evaluated by analyzing the distributions of the settlements and vertical stress beneath the concrete slab.

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Assessment for Vertical Earth Pressure of Roadbeds Applied to Slab Track Structure by Real-scale Loading Tests (실대형 재하시험을 통한 슬래브궤도 노반의 연직토압 평가)

  • Lee, Tae-Hee;Lee, Jin-Wook;Won, Sang-Soo;Lee, Seong-Hyeok
    • Proceedings of the KSR Conference
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    • pp.2057-2063
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    • 2011
  • Recently, concrete slab track is mostly used to satisfy requirements for safety of high-speed train operation and economical efficiency of maintenance. Due to structural characteristics of ballast track structures, roadbeds under the ballast experience a state of high stress. In case of slab track structures, however, its roadbeds place on a condition of low stress less than roadbeds of ballast track structures as increasing of the loading area. In this study, vertical earth pressure under slab track structures was investigated through real-scale loading tests and theoretical analysis to compare with each other.

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A Study on the Laterally Dynamic Characteristics and the Finite Elements of Concrete Slab Track (슬래브궤도에 대한 유한요소와 횡방향 동특성에 관한 연구)

  • 조병완;권병윤;태기호;마성운
    • Proceedings of the KSR Conference
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    • pp.500-507
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    • 2001
  • In this study, Interaction among each element was construed by the unit of new stiffness matrix to analyze the finite element about Japanese precast concrete slab track and improved slab track. Dynamic analysis which is assumed a static analysis and a trainload on the transverse and the longitudinal load of the train into a series periodic function was performed by using the common program. And then, the difference of the movement between an improved section and an existing structure type was realized. Longitudinal static analysis indicated that the stress of the improved section is smaller than that of the protrusion of the existing slab track. And static and dynamic analysis on transverse load showed a little decrease of the displacement on new slab track. But the dynamic analysis result showed that new track system was considerably decreased by 30% compared with the existing Japanese slab track.

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Evaluation of Shear Load Carrying Capacity of Lateral Supporting Concrete Block for Sliding Slab Track Considering Construction Joint (타설 경계면을 고려한 슬라이딩 궤도 횡방향 지지 콘크리트 블록의 전단 내하력 평가)

  • Lee, Seong-Cheol;Jang, Seung Yup;Lee, Kyoung-Chan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.1
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    • pp.55-61
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    • 2017
  • Recently several researches have been conducted to develop sliding track system in which friction between concrete track and bridge slab has been reduced. This paper investigated shear load carrying capacity of lateral supporting concrete block which should be implemented to resist lateral load due to train in sliding track system. In order to evaluate shear load carrying capacity of lateral supporting concrete block, analytical model has been developed considering concrete friction and rebar dowel action along construction joint. The proposed model predicted test results on the shear load carrying capacity from literature conservatively by 13~23% because effect of aggregate interlock along crack surface was neglected. Since construction joint status is ambiguous on construction site, it can be concluded that the proposed model can be used for reasonable design of lateral supporting concrete block. Based on the proposed model, design proposal for lateral supporting concrete block has been established.

A Study on Coupling Coefficient Between Rail and Reinforcing Bars in Concrete Slab Track (콘크리트 슬래브궤도에서 레일과 철근 사이의 결합계수에 대한 연구)

  • Kim, Min-Seok;Lee, Sang-Hyeok;Lee, Jong-Woo
    • Journal of the Korean Society for Railway
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    • v.12 no.3
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    • pp.405-411
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    • 2009
  • Railway signaling system in a rapid transit using the ATC system the approved a speed limit to a train and a part of signaling system in a metro approved a distance which is possible to move. Referring to the way of transmitting train control information, there are the one transmitting it to the on-board system of a train using the direct track, the another transmitting it establishing an instrument, and the other transmitting an instrument by a railway track. The one is the method using the direct track as a conductor for composing the part of the track and attaining the information controlling a train by transmitting a signal to the track. It is used for the high-speed railway and the subway. The method using the track attains information by transmitting it to returned information, and the on-board system of a train attains it by magnetic coupling. Because many reinforcing bars on the concrete slab track are used, interaction between a rail and a reinforcing bar that is not produced on ballast track is made. Due to the interaction, the electric characteristic of rail is changed. In the current paper, we numerically computed the coupling coefficient between the rail and the reinforcing bar based on the concrete slab track throughout the model related to the rail and the reinforcing bar using the concrete slab track that is used in the second interval of the Gyeongbu high-speed railway, and we defined the coupling coefficient not changed in the electric characteristic of rail in the condition that there is no interaction between the rail and the reinforcing bar.

Characteristics of Vibration of Track and Vehicle Body According to Type of Track in Tunnel of High-Speed Railway Lines (고속철도 터널에서의 궤도 형식에 따른 궤도와 차체의 진동 특성)

  • Kim, Man Cheol;Jang, Seung Yup
    • Journal of The Korean Society of Civil Engineers
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    • v.26 no.1D
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    • pp.125-132
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    • 2006
  • In the present study, in order to elucidate the vibration characteristics of track and train body according to the type of track in tunnel, the vibration accelerations of the track and the KTX train body have been measured in tunnels of Kyong-Bu high-speed railway(HSR) lines, and the frequency analysis of the measured data has been performed. From this, the vibration characteristics of the track components such as rail, sleeper, ballast and slab, the tunnel lining and the vehicle body according to the type of track are investigated and their relation is analyzed. The test results show that the vibration of rail and vehicle body rapidly increases at 80Hz in tunnel, and that is much higher in the tunnel on which the concrete slab track is placed. According to the results of the present study, rail supporting stiffness can variate the vibration characteristics of the total system including the vehicle, and therefore the correlation between the vibration of vehicle should be taken into account to determine the supporting stiffness of the slab track.

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