• Title, Summary, Keyword: 아스팔트콘크리트 궤도

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Development of Device to Resist Horizontal Displacement of Asphalt Concrete Track (아스팔트콘크리트 궤도용 궤도변위 저항 장치 개발)

  • Lee, Seonghyeok;Yoon, Wooyong;Bae, Younghoon
    • Journal of the Korean Society for Railway
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    • v.19 no.6
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    • pp.744-754
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    • 2016
  • Asphalt concrete track (ACT) is a track system connecting wide sleepers and concrete panels on top of an asphalt concrete layer; such a system requires adequate resistance force against various longitudinal and lateral external loads. In this study, a series of experiments were carried out to assess the longitudinal and lateral resistance force of a wide sleeper and concrete panel type ACT. The required shear resistance force of the horizontal displacement restraint device (HDRD) was evaluated. Furthermore, a concrete block type anchor and a steel pipe type anchor were developed as HDRDs. The shear resistance force was decided based on the experimental results of horizontal shear tests for each anchor system. In addition, proper numbers and arrangement design guidelines for the HDRDs were suggested considering the shear resisting capacity and economics for HDRDs applied to ACT.

3D Dynamic Finite Element Analysis and Corresponding Vibration of Asphalt Track Considering Material Characteristics and Design Thickness of Asphalt Concrete Roadbed Under Moving Load (아스팔트 콘크리트 설계두께 및 재료특성을 반영한 아스팔트 콘크리트 궤도 3차원 이동하중 동적해석 및 진동특성)

  • Lee, SeongHyeok;Seo, HyunSu;Jung, WooYoung
    • Journal of the Korean Society for Railway
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    • v.19 no.1
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    • pp.67-76
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    • 2016
  • The asphalt-concrete trackbed system has many advantages in terms of maintenance and economics. However, methods to investigate practical use corresponding to the development of the trackbed system must be developed. The primary objective of this study was to evaluate the dynamic performance of the asphalt system in accordance with both the elastic and viscoelastic material characteristics and design thickness of the asphalt trackbed. More specifically, in order to reduce the uncertainty error of the Finite Element(FE) model, a three-dimensional full scale FE model was developed and then the infinite foundation model was considered. Finally, to compare the condition of viscoelastic materials, performance evaluation of the asphalt-concrete trackbed system was used to deal with the dynamic amplification factors; numerical results using isotropic-elastic materials in the FE analysis are presented.

Design Graphs for Asphalt Concrete Track with Wide Sleepers Using Performance Parameters (성능요소를 반영한 광폭 침목형 아스팔트콘크리트 궤도 설계그래프)

  • Lee, SeongHyeok;Lim, Yujin;Song, Geunwoo;Cho, Hojin
    • Journal of the Korean Society for Railway
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    • v.19 no.3
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    • pp.331-340
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    • 2016
  • Wheel load, design velocity, traffic amount (MGT), stiffness and thickness of sub-layers of asphalt concrete track are selected as performance design parameters in this study. A pseudo-static wheel load computed considering the dynamic amplification factor (DAF) based on the design velocity of the KTX was applied to the top of asphalt concrete track for full three dimensional structural analysis using the ABAQUS program. Tensile strains at the bottom of the asphalt concrete layer and vertical strains at the top of the subgrade were computed from the structural FEA with different combinations of performance parameter values for one asphalt concrete track section. Utilizing the computed structural analysis results such as the tensile strains and the vertical strains, it was possible to develop design graphs to investigate proper track sections for different combination of the performance parameters including wheel load, design velocity, traffic amount(MGT), stiffness and thickness of asphalt concrete layers for any given design life. By analyzing the proposed design graphs for asphalt concrete track, it was possible to propose simple design tables that can be used by engineers for the effective and fast design of track.

Development of Wide Prestressed Concrete Sleeper for Asphalt Concrete Track (아스팔트 콘크리트 궤도용 광폭 PSC침목 개발)

  • Bae, Young-Hoon;Lee, Seong-Hyeok;Kim, Eung-Rok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.2
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    • pp.34-42
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    • 2018
  • In order to minimize the deformation of asphalt concrete track(ACT) and ensure the structural safety, a wide type concrete sleeper is necessary to distribute vehicle loading and reduce the exposure of the asphalt roadbed. In this research, the wide prestressed concrete(PSC) sleeper for ACT was developed through the shape design and the structural safety was reviewed using finite element analysis. Furthermore, static test, dynamic test and fatigue test were carried out according to EN13230-2 to verify the design appropriateness of the wide PSC sleepers for ACT. The performance test showed that the developed wide PSC sleeper for ACT meets all the performance requirements by European standard.

Application of the Absorbing Boundary Condition in Moving Force Analysis of Asphalt Concrete Track (흡수경계조건의 아스팔트 콘크리트 궤도 동적 해석에의 적용)

  • Lee, Seonghyeok;Chung, Keunyoung;Jung, Wooyoung
    • Journal of the Korean Society for Railway
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    • v.19 no.1
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    • pp.54-66
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    • 2016
  • In this study, the absorbing boundary condition was adopted to prevent elastic wave propagation due to abrupt load condition changes in moving force analysis. It was proven to be effective in reducing inappropriate noise components. Furthermore, to verify whether fixed point excitation in a laboratory test can simulate train movement effectively, the results of dynamic analysis for fixed point excitation and moving force conditions were analyzed. The dynamic stability of an asphalt track structure under a KTX train condition was also studied. Additionally, the dynamic safety of asphalt tracks was verified by comparing the results of a moving force analysis under a KTX train load and a quasi-static analysis under the design standard Korean train load.

Optimal Section of Ballasted Asphalt Track Considering Design Lifetime and Economic Feasibility (설계수명 및 경제성을 고려한 유도상 아스팔트 궤도의 최적 단면 산정)

  • Lee, Seonghyeok;Lee, Jinwook;Lee, Hyunmin
    • Journal of the Korean Society for Railway
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    • v.18 no.3
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    • pp.241-251
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    • 2015
  • Compared with ballasted track (BT), ballasted asphalt track (BAT) has been increasingly adopted in many countries due to its more greatly reduced reinforced roadbed thickness and smaller cumulative plastic deformation, and its advantages in terms of maintenance. In this respect, the authors' previous research includes analysis of BAT sections that show performance similar to that of BT sections of the present specifications; reliability verification of the analysis results through real-sized static and dynamic train-load tests were performed. Based on previous research, this paper estimates the track lifetime using the strain of the lower roadbed according to reinforced roadbed thickness; using probabilistic LCC analysis, this paper presents a BAT section that satisfies the design lifetime and that has performance similar to or higher than that of BT.

Behavior Characteristics of Ballasted Track on Asphalt Roadbed Using Real Scale Test (실대형 실험을 통한 아스팔트 노반상 자갈궤도의 거동 특성)

  • Lee, Seonghyeok;Lee, Jinwook;Lee, Hyunmin
    • Journal of the Korean Society for Railway
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    • v.18 no.3
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    • pp.252-260
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    • 2015
  • Ballasted track on an asphalt roadbed can be beneficial for its various effects such as (i) decreasing of roadbed thickness by dispersing train load; (ii) prevention of both strength reduction and weakening in roadbed system by preventing rainwater penetration; and (iii) reducing maintenance cost by preventing roadbed mud-pumping and frostbite. With these beneficial effects, ballasted track on asphalt roadbed has been widely used in Europe and Japan, and relevant research for applying such ballasted track on asphalt roadbed systems in Korea is ongoing. In this study, full-scale static and dynamic train load tests were performed to compare the performance of ballasted track on asphalt roadbed and ballasted track. The optimum thickness levels of asphalt and reinforced roadbeds, corresponding to the design criteria for reinforced roadbed of high-speed railway, was estimated using the FEM program ABAQUS. Test results show that the earth pressure on reinforced roadbed of ballasted track on the asphalt roadbed was relatively low compared with that of simple ballasted track. The elastic and plastic displacements of simple ballasted track on the asphalt roadbed were also lower than those of ballasted track. These test results may indicate that the use of ballasted track on asphalt roadbed is an advantageous system in view of long-term maintenance.

Investigation of the Bond and Deformation Characteristics between an Asphalt layer and a Concrete Slab used as the Trackbed Foundation of an Embedded Rail System for Wireless Trams (무가선 트램용 매립형궤도 아스팔트 포장층의 부착특성 및 변형발생특성 분석)

  • Cho, Hojin;Kang, Yunsuk;Lee, Suhyung;Park, Jeabeom;Lim, Yujin
    • Journal of the Korean Society for Railway
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    • v.19 no.2
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    • pp.224-233
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    • 2016
  • Embedded Railway Systems (ERS) will be adapted for wireless trams and will be constructed along city roadways. An asphalt layer should be overlaid on top of the concrete slab used as the trackbed structure in order to ensure smoothness and surface levels equal to those of existing road pavement in downtown city areas. However, the characteristics of an asphalt layer when used as overlay pavement for an ERS are complicated and the behavior of this material is not yet well defined and understood. Therefore, in this study, laboratory shear and tensile bond strength tests were conducted to investigate the bonding behavior of an asphalt layer in a multilayered trackbed section of an ERS. For the laboratory tests, a waterproof coating material was selected as a bonding material between the asphalt overlay and a concrete specimen. Valuable design parameters could be obtained based on the tensile and shear bond strength test results, providing information about the serviceability and durability of the overlaid pavements to be constructed alongside the ERS for wireless trams. In addition, a deformation analysis to assess the tensile strain generated due to truck axle loads at the interface between the asphalt layer and the concrete slab was conducted to verify the stability and performance of the asphalt layer.

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.

Development of Cost Estimate System of Construction Equipment through Analysing Its Domestic Rental Market (임대실태 분석을 통한 건설기계경비 산정시스템 개발)

  • Ahn, Bang-Ryul;Tae, Yong-Ho;Suh, Sang-Wook;Huh, Young-Ki
    • Korean Journal of Construction Engineering and Management
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    • v.13 no.6
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    • pp.121-132
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    • 2012
  • The current estimation system of construction equipment cost was first introduced in 1960's when general contractors had ownership of equipment. However, most of construction equipment in construction sites has been rented from equipment leasing company these days. Therefore, the improvement of current cost estimation system is therefore inevitable in order to advance domestic construction industry. This study is aimed to suggest the improved system by analyzing nationwide market rental rates of major construction equipment. A user friendly prototype of actual database grounded on actual market rental rates collected from over 200 leasing companies in the nation was proposed. The database includes various rates and statistics analyzed by different form of contract as well as different region. Using the collected data, "The Cost Estimate System in Construction Equipment Database" was developed by using VBA(Visual Basic for Applications). The system makes users convenient to utilize the rental rates by choosing equipment and region, and various types of contract.