• Title, Summary, Keyword: 플로팅 슬래브 궤도

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Static and Dynamic Behavior at Low-Frequency Range of Floating Slab Track Discretely Supported by Rubber Mounts in Real-Scale Laboratory Test (고무 마운트로 이산 지지되는 플로팅 슬래브 궤도의 실모형 실내 실험에서의 정적 및 저주파 대역 동적 거동)

  • Hwang, Sung Ho;Jang, Seung Yup;Kim, Eun;Park, Jin Chul
    • Journal of the Korean Society for Railway
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    • v.15 no.5
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    • pp.485-497
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    • 2012
  • Recently, with increasing social interests on noise and vibration induced by railway traffic, the application of floating slab track that can efficiently reduce the railway vibration is increasing. In this study, to more accurately understand the dynamic behavior of the floating slab track, a laboratory mock-up test has been performed, and the static and dynamic behaviors at frequency range near the system resonance frequency were explored. Based on the test results, the design of the floating slab track and the structural analysis model used in the design have been verified. The analytic and test results demonstrate that the dominant frequency of the floating slab track occurs at the frequencies between vertical rigid body mode natural frequency and bending mode natural frequency, and the dominant deformation mode is close to the bending mode. This suggests that in the design of the floating slab track, the bending rigidity of the slab and the boundary conditions at slab joints and slab ends should be taken into consideration. Also, the analytic results by the two-dimensional finite element analysis model using Kelvin-Voigt model, such as static and dynamic deflections and force transmissibility, are found in good agreement with the test results, and thus the model used in this study has shown the reliability suitable to be utilized in the design of the floating slab track.

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.

Examination for Structural Safety of Floating Slab Design and Shear Connector (플로팅 슬래브 설계와 전단연결재의 구조안전성 검토)

  • Park, Sung-Jae;Ma, Chang-Nam;Lee, Jong-Ho;Lee, Du-Hwa
    • Proceedings of the KSR Conference
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    • pp.374-374
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    • 2011
  • Recently the construction of railway sections passing the central area of cities and stations under railway lines are increasing, and then it is urgently required to take the countermeasures against the railway vibration and the second-phase noise radiated from it. The most efficient countermeasure, out of technologies developed up to now, is the floating slab track which is the track system isolated from the sub-structure by springs. In other countries, the source technologies for anti-vibration design and vibration isolator - one of key components - have been developed and many installation experiences have been accumulated. However, in Korea, since the system design technology and technologies for key components are not yet developed, the foreign system are being introduced without any adjustment, and the key component, vibration isolator, depends on imports. In this study, based on the results of previous studies of the dust-control device installation using the slab and go through time after lifting impressive when stepped on power generated by the cross-section of the slab and shear connection re-examined the structural stability.

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Evaluation of Dynamic Stability of Precast Floating Slab Track with Vehicle-Track Interaction Analysis (차량-궤도 상호작용 해석을 통한 사전 제작형 플로팅 슬래브 궤도의 동적 안정성 검토)

  • Jang, Dongdoo;Kim, Jin-Ho;Kwon, Se-Gon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.562-568
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    • 2017
  • A precast floating slab track with a 5m slab panel and installed with isolators is proposed to solve the noise and vibration problem at existing elevated railway stations. Thus, the construction can be carried out rapidly without interrupting the train operation. However, dynamic instability problems may be caused by repeated discontinuities in track due to the short slab panel length and excessive rail displacement due to the inherent operation mechanism of a floating system in reducing the vibration. Furthermore, the difference of the supporting stiffness at the transition between the floating track and ballast track may raise problems. In this study, the assessment factors to evaluate the dynamic stability of the precast floating slab track are presented and assessed with the vehicle-track interaction analysis. Through the analysis, all values relevant to the stability at the floating track section are found to be acceptable, and the slab panels at the transition section are designed to satisfy the stability.

Analysis of Improvement Floating Slab Track for Rapid Transit Railway (형상을 개선한 고속철도용 플로팅 슬래브궤도의 정적해석)

  • Kim, Yong-Jae;Park, Sung-Jae;Jeon, Jong-Su;Park, Myung-Gyun;Park, Man-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.207-208
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    • 2009
  • In this study, floating slab system which is one of the solution to avoid noise and vibration in railway has been introduced, and preliminary analysis and vibration absorber of floating slab system according to the isolator has been introduced.

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Application possibility of dowel bar in low floating slab system (다우얼 바의 저진동 슬래브 궤도 시스템 적용 가능성)

  • Park, Sung-Jae;Kim, Yong-Jae;Park, Myoung-Gyun;Jeon, Jong-Su;Lee, Du-Hwa;Park, Man-Ho
    • Proceedings of the KSR Conference
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    • pp.665-670
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    • 2009
  • From the result of preceding study, there is no reinforcement such as dowel bar or etc. in Joint system of floating slab. Length of floating slab in preceding study is short than one of this study. If there is no reinforcement in the joint of long slab span, fracture of slab is predicted by difference between two slabs. Therefore using of dowel bar is demanded. In this study, General characteristic and preceding technology of dowel bar is researched for data of analysis study. And it is considered application of dowel bar in floating slab system.

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Analysis of Dynamic Behavior of Floating Slab Track Using a Nonlinear Viscoelastic Spring Model (비선형 점탄성 스프링 모델을 이용한 플로팅 슬래브 궤도의 동적 거동 해석)

  • Jang, Seung Yup;Park, Jin Chul;Hwang, Sung Ho;Kim, Eun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.11
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    • pp.1078-1088
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    • 2012
  • Recently, the vibration and structure-borne noise induced by passing trains are of great concerns, and the floating slab track is highlighted as one of most efficient alternatives to reduce the railway vibration. However, due to the non-linearity and viscosity of rubber spring used in the floating slab track, its dynamic behavior is very complex. In this study, therefore, to simulate the dynamic behavior of floating slab track with a better accuracy, a nonlinear viscoelastic rubber spring model that can be incorporated in commercial finite element analysis codes has been proposed. This model is composed of a combination of elastic spring element, friction element and viscous element, and termed the "generalized friction viscoelastic model(GFVM)". Also, in this study, the method to determine the model parameters of GFVM based on Berg's 5-parameter model was presented. The results of the finite element analysis with this rubber spring model exhibit very good correlation with the test results of a laboratory mock-up test, and the feasibility of GFVM has been verified.

Dynamic Behavior of Train and Track at Slab Joints of Floating Slab Track (플로팅 슬래브궤도 슬래브 연결부에서의 차량 및 궤도의 동적 거동)

  • Jang, Seung-Yup;Yang, Sin-Chu;Hwang, Sung-Ho;Ahn, Mi-Kyung;Choi, Won-Il
    • Proceedings of the KSR Conference
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    • pp.993-997
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    • 2011
  • Highlighted is significance of the floating slab track for mitigating vibrations induced by train, together with the recent trends towards speed-up of railways. In the design of the floating slab track, it is more beneficial to increase the slab length since a significant impact can be induced on the train and track at the discontinuous points between slabs with the finite slab length. However, if the slab length is too long, the tensile stress of slab concrete and the additional stress on rail due to the temperature change and shrinkage of concrete slab. Thus it is of great importance to relevantly determine the slab length. In this study, to understand these phenomena and establish the countermeasures, the dynamic behaviors of train and track at the inter-slab discontinuous points have been explored and the effect of dowel joints as one of countermeasures has been analytically investigated.

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A Study of Noise Characteristics Induced by Slab Vibration for the Elevated Railway Station (선하역사의 슬래브 진동에 의한 소음방사 특성에 관한 연구)

  • Kim, Jin-Ho;Jang, Dongdoo;Ji, Yong-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.5
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    • pp.3557-3566
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    • 2015
  • In the case of elevated railway station in which railway is connected with superstructure of station, vibration and noise level is relatively higher than those of general structure type station due to structural characteristic which transmits vibration directly. Therefore, characteristic understanding of structural vibration and accompanying structure cause noise and establishment of reduction plan through the results are in need. Test and analysis are performed in this research to consider correlativity between structural vibration and accompanying structure cause noise when external forces are applied on standard slab and floating slab which is able to isolate vibration. By producing and loading on standard and floating slab, vibration and noise response are measured while simulation using numerical analysis, finite element method and SEA method is performed. The results about structural dynamic behavior of slab, correlativity between structural vibration and noise, reduction performance of floating slab is deduced through the analysis of tests.