• Title/Summary/Keyword: 콘크리트침목

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Cause Analysis for Sleeper Damage of Sleeper Floating Track in Urban Transit (도시철도 침목플로팅궤도의 침목손상 원인 분석)

  • Choi, Jung-Youl;Shin, Hwang-Sung
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.6
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    • pp.667-674
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    • 2022
  • In this study, the correlation between the damage type and operating conditions of the sleepers was analyzed based on the design data and visual inspection results for the concrete sleepers of the sleeper floating track (STEDEF) that have been in operation for more than 20 years. It appeared in the form of cracks, breakages, and breaks in the concrete at the center and tie bar contact and buried areas. As a result of the numerical analysis, it was analyzed that the change in the left and right spring stiffness of the sleeper resilience pad increases the maximum stress, tensile stress, compressive stress, and displacement of the concrete sleeper, and stress concentration in the concrete at the tie bar contact area. It was proved analytically that the sleeper resilience pad can affect the damage of the concrete sleeper. Therefore, damage of concrete sleepers in the sleeper floating track in urban transit could be caused by changes in spring stiffness of sleeper resilience pads. It was reviewed that preventive maintenance such as improvement and timely replacement of sleeper resilience pads was necessary.

Damage Cause Analysis of Concrete Sleepers for Sharp Curved Track on Urban Railway Bridge (도시철도 교량상 급곡선 자갈궤도용 콘크리트침목 손상원인 분석)

  • Choi, Jung-Youl;Shin, Tae-Hyoung;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.3
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    • pp.517-522
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    • 2021
  • In this study, the causes of damage to the concrete sleepers in a ballast track with under sleeper pads attached to the base of the sleepers installed in the sharp curved track(R=180m) of the urban railway bridge were analyzed. The damage types of concrete sleepers were investigated, and the correlation with track irregularity was reviewed. Also, stress generated in the concrete sleeper was reviewed through structural analysis. As a result, most of the cracks of the sleepers occurred in the section with severe track irregularity. In addition, as a result of the analysis, the stress generated in the track components and the sleepers was found to be reduce in the fastening system using the 4-anchor.

A Study on Estimation Method of Concrete Sleeper Strength for Sleeper Floating Track using Rebound Hardness Test Method (반발경도법을 이용한 침목플로팅 궤도의 콘크리트 침목 강도추정 기법 연구)

  • Chung, Jee-Seung;Lee, Jeong-Sug;Choi, Jung-Youl
    • The Journal of the Convergence on Culture Technology
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    • v.8 no.3
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    • pp.277-282
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    • 2022
  • The sleeper floating track (STEDEF) in this study was a track type in which a very soft resilience pad was installed under a relatively thin concrete sleeper (RC Block). Therefore it was expected that the resilience pad could affect the estimation results of the concrete strength. In this study, field applicability evaluation was performed to apply the rebound hardness test method, which was a general method for estimating the compressive strength of concrete in civil structures, to concrete sleepers of railway tracks. In order to analyze the strength estimation technique of concrete sleepers reflecting the characteristics of track structures different from those of civil structures, the parameter experiments that could affect the strength estimation results of concrete sleepers in a serviced line were performed. As a result of the study, the appropriate hitting position was suggested considering the shape of the concrete sleeper, and the difference in strength estimation results according to the condition of the concrete sleeper and supporting conditions was derived.

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.

Natural Frequency Analysis of Sleeper Floating Track System using Modal Test Technique (모달시험기법을 이용한 침목플로팅궤도의 고유진동수 분석)

  • Jung-Youl Choi
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.3
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    • pp.833-838
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    • 2024
  • The urban railway sleeper floating track(STEDEF) is a structure that structurally separates the sleepers and the concrete bed using sleeper boots and resilience pads to reduce vibration transmitted to the concrete bed. Recently, the resilience pads of sleeper floating tracks that have been in use for more than 20 years are deteriorating. Accordingly, in order to evaluate the performance of the resilience pad, a static spring stiffness test is being performed after extracting the resilience pad. This evaluation technique is performed after replacing the resilience pad in use. However, the track natural frequency can change depending on the resilience pad spring stiffness and the uplift and subsidence of the concrete bed. In this study, modal testing technique was used to evaluate the track natural frequency. For this purpose, the sleeper boots material, resilience pad spring stiffness, and track natural frequency according to concrete bed uplift and subsidence were measured using modal tests at a laboratory scale. It was analyzed that the natural frequency of the sleeper floating track was directly affected by changes in the spring stiffness of the resilience pad. In addition, the change in natural frequency due to the uplift and subsidence of the concrete bed was also found to be large. Therefore, it is believed that the modal test technique presented in this study can be used to evaluate the resilience pad deterioration and voided sleepers.

An Investigation on Recycling of Prestressed Concrete Sleepers (프리스트레스트 콘크리트 침목의 재활용 기술에 대한 고찰과 기초 실험)

  • Jae-Young Lee;Uijun Lee;Jaewon Lee;Sunmo Yang;Seongwoo Gwon
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.11 no.4
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    • pp.316-323
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    • 2023
  • The need for sustainable waste management has intensified the focus on recycling prestressed concrete sleepers used in railways. Given their high volume and environmental impact at the end of their service life, finding efficient recycling methods is crucial. This study explores current recycling approaches, particularly mechanical techniques, evaluating their advantages, limitations, and economic feasibility. Finally, an example of mechanical recycling was performed. The analysis results of the resulting recycled aggregates are suggested. Then, the non-cement concrete mixtures with recycled aggregates were designed, and their strength development was analyzed.

Development of Automatic Crack Identification Algorithm for a Concrete Sleeper Using Pattern Recognition (패턴인식을 이용한 콘크리트침목의 자동균열검출 알고리즘 개발)

  • Kim, Minseu;Kim, Kyungho;Choi, Sanghyun
    • Journal of the Korean Society for Railway
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    • v.20 no.3
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    • pp.374-381
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    • 2017
  • Concrete sleepers, installed on majority of railroad track in this nation can, if not maintained properly, threaten the safety of running trains. In this paper, an algorithm for automatically identifying cracks in a sleeper image, taken by high-resolution camera, is developed based on Adaboost, known as the strongest adaptive algorithm and most actively utilized algorithm of current days. The developed algorithm is trained using crack characteristics drawn from the analysis results of crack and non-crack images of field-installed sleepers. The applicability of the developed algorithm is verified using 48 images utilized in the training process and 11 images not used in the process. The verification results show that cracks in all the sleeper images can be successfully identified with an identification rate greater than 90%, and that the developed automatic crack identification algorithm therefore has sufficient applicability.

Using the Turnout Reinforced Concrete Sleeper on Slab Track (콘크리트 도상 분기 침목의 R.C 침목화)

  • 이상진;김기훈;신순호;이인세
    • Proceedings of the KSR Conference
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    • 2002.10a
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    • pp.633-641
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    • 2002
  • Wooden-sleeper, which has been adopted as railway turnout in Korea, has created many problems such as short life span and increase of maintenance cost. Especially turnout on Maintenance Free slab track, which has been used in city metro, has been constructed with wooden sleeper buried in concrete roadbed due to complexity of structure. However, such problem as rapid erosion in subground makes it difficult to maintain the sleeper because of frequent replacement required. Therefore, the objective of this paper is to introduce design and construction of reinforced concrete(R.C) sleeper for turnout on the concrete roadbed to facilitate maintainability and economic construction of turnout.

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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.

Evaluation on Damage Effect of Concrete Track induced by Underground Structure Displacement Behavior (지하구조물 변위거동에 따른 콘크리트궤도의 손상영향 분석)

  • Jung-Youl Choi
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.3
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    • pp.839-844
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    • 2024
  • This study analytically analyzed the impact of underground structure displacement behavior on track damage due to adjacent excavation work, ground deterioration, and changes in groundwater level. The concrete track that was the subject of the study was analyzed for sleeper floating track(STEDEF) and precast concrete slab track(B2S). Sleeper floating track is a track structure in which the concrete bed and sleepers are voided. precast concrete slab track is a track structure that induces the elastic behavior of the rail by assembling rails and fasteners using slabs. For numerical analysis, each concrete track, from rail to concrete bed, was modeled as three-dimensional elements. In addition, the displacement behavior of the underground structure was set as a variable to analyze the damage effect on the concrete bed. Using numerical analysis, the concrete bed stress due to uplift and subsidence was analyzed, and the level of crack effect was analyzed by comparing it to the tensile strength and shear strength. As a result of the analysis, it was found that the sleeper floating track was more vulnerable than the precast concrete slab track when the same uplift and subsidence occurred. In addition, uplift and subsidence, it was analyzed that the cracks range in the sleeper floating track was large.