• Title, Summary, Keyword: 콘크리트궤도

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Analysis of Iron-filings Trapping Characteristics on Concrete Slab Track using Permanent Magnet (영구자석을 이용한 콘크리트 궤도상의 쇠가루 포집장치 특성 분석 연구)

  • Park, Chan-Bae;Lee, Ju
    • Journal of the Korean Society for Railway
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    • v.14 no.4
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    • pp.348-353
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    • 2011
  • Iron fillings which were accumulated around the rail was often the cause of abnormal signal in case of signaling equipment using rail as transmission line. Iron fillings were generated on curved section of railroad due to the friction between rail and wheel, and metro line company urged to find the way to remove these iron fillings, because these were often the cause of abnormal signal. Magnetic device for trapping iron fillings around concrete slab tracks is introduced. The characteristics of magnetic device were analyzed using basic design and numerical analysis method. Magnetic device for trapping iron fillings were examined for application to the train which were operating in commercial line.

A Study on the Evaluation of Track Support Stiffness on the Various Track Type in Urban Transit (도시철도 궤도구조별 궤도지지강성 평가를 위한 실험적 연구)

  • Lee, Dong-Wook;Park, Yong-Gul;Choi, Jung-Youl
    • Journal of the Korean Society for Railway
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    • v.14 no.3
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    • pp.262-270
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    • 2011
  • Track support stiffness which affected track maintenance and riding comfort had a big effect on the track and train. Also, track support stiffness of the track design which was based on theory differs from track support stiffness of the track generated on the field. Track support stiffness was generated by several factors such as dynamic wheel loads, vertical displacement of track, and stress at rail bottom on the field test. With the results of the field test was compared with theoretical value. This paper analyzed that track support stiffness of ballast depended on condition of ballast, and support stiffness of concrete track also depended on the characteristic of track structures such as, normal elastic fastening system, rail floating system and sleeper floating system. However, on the ballast and concrete track, the designed track support stiffness was underestimated less than the measured track support stiffness. When the track condition was estimated on service line, it would not consider the track condition on the field. Therefore, this study proposed the various track type and the range of track support stiffness based on the experimental test.

Evaluation of Shear Load Carrying Capacity of Lateral Supporting Concrete Block for Sliding Slab Track Considering Construction Joint (타설 경계면을 고려한 슬라이딩 궤도 횡방향 지지 콘크리트 블록의 전단 내하력 평가)

  • Lee, Seong-Cheol;Jang, Seung Yup;Lee, Kyoung-Chan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.1
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    • pp.55-61
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    • 2017
  • Recently several researches have been conducted to develop sliding track system in which friction between concrete track and bridge slab has been reduced. This paper investigated shear load carrying capacity of lateral supporting concrete block which should be implemented to resist lateral load due to train in sliding track system. In order to evaluate shear load carrying capacity of lateral supporting concrete block, analytical model has been developed considering concrete friction and rebar dowel action along construction joint. The proposed model predicted test results on the shear load carrying capacity from literature conservatively by 13~23% because effect of aggregate interlock along crack surface was neglected. Since construction joint status is ambiguous on construction site, it can be concluded that the proposed model can be used for reasonable design of lateral supporting concrete block. Based on the proposed model, design proposal for lateral supporting concrete block has been established.

Fracture Behavior of Dowel Joint of Concrete Slab Track (콘크리트궤도 슬래브의 다웰 연결부 파괴 거동)

  • Kwon, Kusung;Jang, Seung Yup;Chung, Wonseok
    • Journal of The Korean Society of Civil Engineers
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    • v.33 no.5
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    • pp.2125-2133
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    • 2013
  • Recently, an interest on joint behavior between adjacent concrete slab tracks has increasing due to large application of such track system. Dowel bars are widely used to improve load transfer capacity across the joints. Dowel bars reduce the deflections and stresses by transferring the load between the slabs. This study proposes the lumped shear spring model to efficiently model dowel joints of adjacent slabs. This model includes bearing stiffness between dowel bar and concrete as well as dowel gap. Strength of the proposed spring model is evaluated based on Concrete Capacity Design method under the assumption of shear failure mode in the joints. Experiments are also performed up to failure to evaluate the accuracy of the proposed model. It has been observed that the proposed model is able to predict initial nonlinearity due to dowel gap, and capture material nonlinearity of the test slabs. Thus, it is recommended that the proposed model can be effectively applied to the dowel joints of concrete slab track.

Fatigue Life Evaluation for Used Rail on Track Types (궤도형식별 사용레일의 피로수명 평가)

  • Kang, Sung Won;Lim, Hyung-Jun;Park, Yong-Gul
    • Journal of the Korean Society for Railway
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    • v.20 no.5
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    • pp.649-657
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    • 2017
  • In this study, fatigue testing was carried out for long-term use of rail according to track type. From S-N curves for 50%~0.01% failure probability, the fatigue life of the long-term use rail for each track type was derived using the weight probability analysis technique on the experimental data. Because the rails used in the fatigue test have different cumulative tonnages, the number of repetitions was modified by averaging the cumulative tonnage. In addition, the bending stresses of rail bottoms, considering rail surface irregularities, track support stiffnesses and train speeds, were evaluated using the predicted rail bending stresses derived from existing studies. As a result, for rail fatigue life evaluation, the fatigue life of rail on the ballast track was found to be more than 200 million tons higher than the standard value for rail replacement. Also, the fatigue life of rail on concrete track is more than 300 million tons higher than that on ballast track. The Haibach rule is adaptable for the fatigue life evaluation of rail for stress range under fatigue limit.

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.

Effects of Transverse Cracks on Stress Distributions of Continuously Reinforced Concrete Tracks Subjected to Train Loads (연속철근 콘크리트궤도의 횡균열이 열차 하중에 의한 응력 분포에 미치는 영향)

  • Bae, Sung Geun;Choi, Seongcheol;Jang, Seung Yup;Cha, Soo Won
    • Journal of the Korean Society for Railway
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    • v.17 no.5
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    • pp.355-364
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    • 2014
  • The restrained volume changes of concrete due to variations of temperature and moisture produce transverse cracks in continuously reinforced concrete tracks (CRCTs). Such cracks are known to significantly affect the behaviors and long-term performance of CRCT. To investigate the effects of the transverse cracks on the behavior of CRCT and to develop more reasonable maintenance standards for cracks, in this study, the stress distribution of the track concrete layers (TCL) and the hydraulically stabilized base course (HSB) with transverse cracks were numerically predicted by a three dimensional finite element analysis when CRCT was subjected to train loads. The results indicate that the bending stresses of TCL and vertical stresses at the interfaces between TCL and HSB increased as the cracks were deepened. In addition, vertical stresses were locally concentrated near reinforcing steel in cracks in TCL when full-depth cracks developed, which may lead to punch-outs in CRCTs. Comparably, the effects of crack width and spacing were not as significant as crack depth. This study indicates that ensuring the long-term performance of CRCTs requires adequate maintenance not only for crack width and spacing but also for crack depth. Our results also show that locating HSB joints between sleepers is beneficial to the long-term performance of CRCTs.

A Study on Coupling Coefficient Between Rail and Reinforcing Bars in Concrete Slab Track (콘크리트 슬래브궤도에서 레일과 철근 사이의 결합계수에 대한 연구)

  • Kim, Min-Seok;Lee, Sang-Hyeok;Lee, Jong-Woo
    • Journal of the Korean Society for Railway
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    • v.12 no.3
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    • pp.405-411
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    • 2009
  • Railway signaling system in a rapid transit using the ATC system the approved a speed limit to a train and a part of signaling system in a metro approved a distance which is possible to move. Referring to the way of transmitting train control information, there are the one transmitting it to the on-board system of a train using the direct track, the another transmitting it establishing an instrument, and the other transmitting an instrument by a railway track. The one is the method using the direct track as a conductor for composing the part of the track and attaining the information controlling a train by transmitting a signal to the track. It is used for the high-speed railway and the subway. The method using the track attains information by transmitting it to returned information, and the on-board system of a train attains it by magnetic coupling. Because many reinforcing bars on the concrete slab track are used, interaction between a rail and a reinforcing bar that is not produced on ballast track is made. Due to the interaction, the electric characteristic of rail is changed. In the current paper, we numerically computed the coupling coefficient between the rail and the reinforcing bar based on the concrete slab track throughout the model related to the rail and the reinforcing bar using the concrete slab track that is used in the second interval of the Gyeongbu high-speed railway, and we defined the coupling coefficient not changed in the electric characteristic of rail in the condition that there is no interaction between the rail and the reinforcing bar.

Prediction of Crack Pattern of Continuously Reinforced Concrete Track Induced by Temperature Change and Shrinkage of Concrete (온도 변화와 콘크리트 수축에 의한 연속철근 콘크리트궤도의 균열 발생 패턴 예측)

  • Bae, Sung Geun;Choi, Seongcheol;Jang, Seung Yup;Cha, Soo Won
    • Journal of the Korean Society for Railway
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    • v.17 no.4
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    • pp.270-280
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    • 2014
  • In this study, to examine the causes of cracks in continuously reinforced concrete tracks (CRCTs) and the main factors affecting cracking, a field survey on the status of cracks and crack patterns in the Gyeong-bu high speed line was conducted, and the crack patterns of CRCT due to the temperature difference between the top of the slab (TCL) and the bottom of the subbase (HSB) and the drying shrinkage of concrete were predicted by a nonlinear finite element model considering the structure of CRCT. The results of the numerical analysis show that cracks will be developed at the interface between the sleeper and the TCL, and under the sleeper due to the temperature difference and concrete shrinkage. This corresponds well to the crack locations found in the field. Also, it is found that the most significant factors are the coefficient of thermal expansion with respect to the temperature difference, and the drying shrinkage strain with respect to shrinkage. According to the results, the reinforcement ratio should be carefully determined considering the structures of CRCT because the crack spacing is not always proportional to the reinforcement ratio due to the sleepers embedded in the TCL.