• Title, Summary, Keyword: slab panel track

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Free vibrations of precast modular steel-concrete composite railway track slabs

  • Kimani, Stephen Kimindiri;Kaewunruen, Sakdirat
    • Steel and Composite Structures
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    • v.24 no.1
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    • pp.113-128
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    • 2017
  • This paper highlights a study undertaken on the free vibration of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an evolvement from the slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both eigenfrequencies and eigenmodes have been extracted using the Lanczos method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.

Damped frequencies of precast modular steel-concrete composite railway track slabs

  • Kaewunruen, Sakdirat;Kimani, Stephen Kimindiri
    • Steel and Composite Structures
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    • v.25 no.4
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    • pp.427-442
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    • 2017
  • This paper presents unprecedented damped oscillation behaviours of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an innovative slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both undamped and damped eigenfrequencies and eigenmodes have been extracted using the Lancsoz method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.

A Study to select the optimum size for the panel of the precast slab track system (프리캐스트 슬래브궤도 패널의 최적규격 선정을 위한 연구)

  • Kim, Yoo-Bong;Moon, Do-Young;Beak, In-Hyuk
    • Proceedings of the KSR Conference
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    • pp.740-744
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    • 2011
  • Precast slab track system(PSTS) is a concrete track laying system where the slab panels are pre-manufactured in factories and assembled and installed on-site. PSTS has been developed for the past 30 years in countries where railway technologies are advanced such as Japan and Germany to improve the various drawbacks of the in-situ concrete slab track. However, the usefulness of PSTS is being continuously approved by many other countries such as China, Taiwan, Austria, Italy, Spain, etc,. Lately, not only Japan and Germany, but also Austria, Italy and China have developed their own PSTS by collaboration between their Governments and private enterprises and are now attempting to expand their businesse soverseas. In accordance to such movement, in 2006, the Korean Railroad Research Institution and Sampyo E&C have developed a Korean PSTS by joint research. PSTS consists of concrete panel, under pouring layer and concrete base layer. Amongst these components, the panel is the main component of PSTS which supports the train load and has a great effect on the track quality, workability and economics. Therefore, a study is to be conducted to select the optimum size for the Panel of the precast slab track system panel by analyzing the various standards & forms, interpretation of finite elements of the selected model and economical analysis.

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Development of Prefabricated Slab Panel for Asphalt Concrete Track (아스팔트 콘크리트 궤도용 사전제작형 슬래브 패널 개발)

  • Baek, In-Hyuk;Lee, Seong-Hyeok;Shin, Eung-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.3
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    • pp.75-82
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    • 2019
  • Slab panels are very important to develop asphalt concrete (AC) track for minimizing the roadbed stress due to the train load and reducing the plastic deformation of infrared-sensitive AC. In this study, the slab panel for AC track was developed through the shape design and the indoor performance test and its structural integrity has been investigated through the finite element analysis under the flexural tensile stress and the design moment according to various static load combination by KRL-2012 standard train load model and KR-C code. In order to verify the suitability of the slab panel for AC track, static bending strength test and dynamic bending strength test were performed according to EN 13230-2. Results show that the slab panel for AC track satisfies all the performance standards required by European standards such as crack loads and crack extension.

Design of Korean Precast Slab Track (한국형 프리캐스트 슬래브 궤도 설계)

  • Zi, Goang-Seup;Lee, Seung-Jung;Jang, Seung-Yup
    • Proceedings of the KSR Conference
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    • pp.1423-1429
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    • 2010
  • We proposed a design procedure for Korean Precast Slab Track system. Korean Precast Slab Track system cannot use the same design procedure to German slab track system because of different shapes and some problems. We identified the problems of German slab track design system that cannot simulate effects of loads. This proposed procedure is implemented for the commercial software of ABAQUS. Using this procedure, one can consider uncombined effects between slab panel and hydraulic sub base, effect of close sleepers.

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3- D Analysis of Concrete Slab Track System (콘크리트 슬래브 궤도의 3차원 거동해석)

  • Kim, Jeong-Il;Jang, Seung-Yup
    • Proceedings of the KSR Conference
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    • pp.955-960
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    • 2004
  • In this study, three dimensional FE analysis of concrete slab track has been performed in order to develop the realistic design of precast concrete slab track. The precast slab track system including the precast concrete slab panel and the grout layer is modeled using the three dimensional solid element with crack softening effect. The input load is computed from the one dimensional beam element model constituting the rail and several discrete springs. To investigate the effect of the longitudinal connection of slab panels, two different systems-continuous and discrete systems - are modeled. The analytical results show that the stresses of both the slab panel and the grout layer are in the range of linear elastic, and, at the interface between two adjacent panels, the primary stresses of the grout layer of the discrete system are higher than those of the continuous system. However, The overall stress levels of the grout layer are very low relative to the strength of th grout.

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The effect of the poor infilling of the underpouring in precast slab track system on structural behavior (프리캐스트 슬래브 궤도 시스템의 충전층 충전불량이 궤도구물의 구조적 안전성에 미치는 영향)

  • Kim, Yoo-Bong;Kang, Young-Jong;Moon, Do-Young;An, Ki-Hong
    • Proceedings of the KSR Conference
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    • pp.256-260
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    • 2010
  • It has been proved that precast slab track has advantage of rapid construction speed and good quality compared to in-situ concrete slab track. A korean precast slab track, which is named as a K-PST, was developed and had been installed on the embankment and explored on the air. The developed track system consists of precast track panel and underpouring layer which is made of cement-asphalt mortar. Consequently, poor filling of underpouring layer directly could affect on the long-term performance of the track system. As a preliminary study, the effect of the poor infilling of the underpouring in precasst slab track system on structural behavior was investigated through FEM analysis.

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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.

Evaluation of the Dynamic Stability of Subway Bridge in the Applying B2S Track (B2S궤도 적용에 따른 철도교량의 동적안정성 검토)

  • Kong, Sun-Yong;Kim, Sang-Jin;Baik, Chan-Ho
    • Proceedings of the KSR Conference
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    • pp.20-27
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    • 2009
  • This paper presents an analytic study for replacement of the ballast track in existing subway bridge by the Precast slab panel(B2S) track. To evaluate the dynamic responses on application of B2S track, the time history analysis with the 3D modeling. A total of two models, which were one ballast track bridge and B2S track bridge, were used in the FE analysis. The results of this study show that the dynamic displacement and acceleration of the B2S track bridge were significantly reduced for a higher train speed, compared to the ballast track bridge. Also, the replacement of the ballast track bridge in existing subway bridge by the B2S track increased the structural safety of bridge and ensured sufficient dynamic stability and serviceability. As a result, the servicing subway bridge with B2S track system has need of the reasonable measures which could be reducing the static and dynamic response and improving the performance.

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Physical Properties according to Temperature Change of the Cement-Asphalt Mortar for Precast Slab Track (프리캐스트 슬래브 궤도용 시멘트-아스팔트 유제 혼합 모르타르 충전재의 온도변화에 따른 물리적 특성)

  • Oh, Soo-Jin;Lee, Hu-Sam;Jang, Seung-Yup;Jeong, Yong;Jung, Young-Min;Yoon, Seob
    • Proceedings of the KSR Conference
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    • pp.1273-1278
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    • 2007
  • The cement-asphalt mortar is a mixture of cement and asphalt emulsion, and is utilized as a underpouring materials for the railway track which is used to fill under slab panel space so as to provide a stabilized track support and a tool for reduction of noise and vibration. To increase the workability of grouting, this study investigates the effect of temperature on cement-asphalt mortar by analyzing its physical and mechanical properties before/after hardening according to the temperature (10, 15, 20, 25, $30^{\circ}C$). According to the test results, it is found that as for the physical property of fresh cement-asphalt mortar the more mixture temperature become higher or lower, the more fluidity become worse. But by increasing reducing agent amount and its unit quantity, the required fluidity is met. The compressive strength as physical property of hardened cement-asphalt mortar become lower when temperature is lower but taking it by and large the physical properties of cement-asphalt mortar before/after hardening aren't so affected by temperature and well satisfy the requirement. And it has proved that rate of expansion and freezing and thawing resistance aren't affected by temperature.

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