• Title, Summary, Keyword: 콘크리트궤도

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Evaluation of Dynamic Stability for Structural Bar Reinforced Precast and Prestressed Retaining Wall for Moving Train Load (이동열차하중에 대한 강봉으로 보강된 프리캐스트 프리스트레스트 옹벽의 동적 안정성 평가)

  • Lee, Il Wha;Um, Ju Hwan;Lee, Kang Myung;Keum, Chang Jun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.5
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    • pp.190-198
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    • 2011
  • The precast production has many advantages by fast construction period, labor-saving and high quality. In recent years, the application of the precast product has been increased in the earth retaining wall field. This paper presents the results of the numerical analysis that was carried out to evaluate the dynamic stability of precast and prestressed earth retaining wall under moving train load. The two-dimensional FEM analysis was used to the numerical analyses. The train load to act on trackbed is combined by the real measured roughness phase angle and quasi-static load. The dynamic stability is analysed by the displacement, acceleration and stress under moving train load at each specified location. The results of the analysis show that the precast and prestressed retaining wall has very stable capability for the railway.

Enhanced Method for Environmental Benefit via Application of Low Impact Development (LID) Technique in Tram Design (트램 설계시 LID 기법 적용을 통한 환경편익 증대 방안)

  • Gu, Su-Hwan;Lee, Yunhee;Oa, Seong-Wook
    • Journal of the Korean Society for Railway
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    • v.19 no.6
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    • pp.826-832
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    • 2016
  • Reduced greenhouse gas effect induced by LID (Low Impact Development) technique application in tramway construction was quantified to increase environmental benefit as part of an overall economic assessment. In addition, by application of penetration type permeable blocks, the effect of the urban water cycle was examined as a special assessment item in the policy analysis. The carbon emission ratios of the permeable turf block, according to the turf coverage rate (100%, 50% granite, and 50% HDPE), against the concrete track construction were -184.7%, -127.3%, and -116.3%, respectively. The carbon emission ratios of permeable blocks with granite and HDPE were 30.1% and 52.5%. In the case of the penetration type permeable block, it was possible to store rainfall in the block until 90mm/hr of rainfall intensity (94.3% of water reserve rate); therefore, this method was effective as part of the urban water cycle system. As a result, an increased environmental benefit from LID technique application is expected in tramway construction; this needs to be considered as a policy factor in AHP analysis.

Behavior of Tension Clamp in Rail Fastening System (레일 체결장치 텐션클램프의 거동)

  • Choi, Shin-Hyung;Park, Beom-Ho;Yun, Kyung-Min;Bae, Hyun-Ung;Lim, Nam-Hyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.12
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    • pp.8812-8819
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    • 2015
  • In a situation in which importance of rail fastening system is growing with increasing the construction of concrete track, an accident of tension clamp(the component of rail fastening system) breaking has been recently occurred. This results from various factors such as field condition, operating agency, running condition, traffic frequency and so on. Thus, the study for the behavior of tension clamp is required. In this paper, an experiment and finite element analysis(FEA) have been performed to analyse the mechanical behavior of tension clamp. The stress and displacement of tension clamp have been analyzed as the clamping force through a laboratory test, and they were compared with FEA results. Furthermore, the stress and displacement of the tension clamp are derived from train load condition applying the verified model, and the fatigue vulnerability of the tension clamp is identified through stress analysis.

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.

Dynamic Interaction Evaluation of Maglev Vehicle and the Segmented Switching System (자기부상열차 차량과 분기기 동적상호작용 시험 평가)

  • Lee, Jong-Min;Han, Jong-Boo;Kim, Sung-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.2
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    • pp.576-582
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    • 2017
  • The switching system in a maglev train is an indispensable element for distributing train routes, and it should be designed to ensure safe operation. Unlike conventional wheels on rails, the switching track in EMS-type maglev is supported by a group of 3 to 4 steel girders. When the vehicle changes its route, the segmented track allows the girders to change from a straight position to a curved one with a small radius of curvature. Hence, the structural characteristics of the segmented switching system may affect the levitation stability of the maglev vehicle. This study experimentally evaluates the dynamic interaction between maglev vehicles and a segmented switching system. The results may be helpful for improving the switching system. The measured levitation and lateral air gaps were evaluated at a vehicle speed of 25 km/h, and the ride quality of the Maglev vehicle was determined to be "comfortable" according to the UIC 513 standard.

A study on the Vibration Reduction of the Commercial High-speed Train (운영 중인 고속열차의 진동저감에 관한 연구)

  • Jeon, Chang-Sung;Choi, Sunghoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.11
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    • pp.697-704
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    • 2017
  • This study was carried out to investigate and alleviate the vibration problem of commercial high-speed trains. First, the measurement of the carbody vibration was performed, in order to determine the vibration level of the high-speed train. The measurement result showed that the vibration level of the driver cab was higher than that of the passenger car and that the vibration became bigger toward the trailing end of the train. The vertical vibration of the driver cab and passenger car was larger than the transverse vibration, and the maximum value of the vibration in the ballast section was larger than that in the concrete section. A dynamic analysis was carried out to improve the vibration of the KTX-Sancheon train. The results of the analysis showed that it is necessary to reduce the vibration of the driver cab and both ends of the passenger cars. To reduce the vibration of the driver cab, it was recommended that the stiffness of the secondary coil spring be reduced and the damping coefficient of the secondary vertical damper be increased. It was found that the failure of the suspension system could be the origin of the vibration problem of the high-speed train. The proper management of wheel wear plays an important role in the improvement of the operation efficiency and reduction of the carbody vibration of high-speed trains, and research is underway to change the present wheel profile to increase the mileage between wheel turning.

Study on Optimal Design of Traverse Switch System for Maglev Train (자기부상열차용 트레버스 분기기 최적설계 연구)

  • Lee, Younghak;Kim, Chang-Hyun;Lee, Jong-Min
    • Journal of the Korean Society for Railway
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    • v.19 no.6
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    • pp.717-726
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    • 2016
  • Emergency tracks are necessary in case a broken down train evacuates, a train needs to make way for a faster train behind it, or a train suddenly stops and following trains must avoid colliding with it. Magnetic Levitated (maglev) Trains can change track to enter an emergency track using a segmented switch or a traverse switch. On a traverse switch, a train can change its track when the part of the track that the train is on moves to the other track. Currently manufactured Maglev trains have two bodies and the total length is 25 meters. If a traverse switch is used, it will only require 30 meters of track to move the train to the other track, so, when it comes to efficiency of costs and space, the traverse switch surpasses the articulated switch. Therefore, in this paper, an optimized design to secure structural safety and weight lightening is suggested. To achieve these results, the heights of the piled concrete and girders which are both placed on the top of the traverse switch, are set as design variables. The Finite Element Method (FEM), in application of kriging and in the design of the experiments (DOE), is used. Maximum stress, deformation, and structural weight are compared with the results, and through this process structural safety and weight lightening is proven.