• Title, Summary, Keyword: Rail Stability

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Review of effects of friction coefficient of moving bearing on Stability of CWR (가동단 마찰계수가 장대레일 축력 안정성에 미치는 영향 검토)

  • Ryu Jae-Nam;Choi Young-Joon;Yang Sin-Chu
    • Proceedings of the KSR Conference
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    • pp.812-817
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    • 2004
  • Recently drastic improvement of railway technology has been accompanied by the construction of very high-speed tracks. It should be noticed that Continuously Welded Rail(CWR) has played significant role in technical development of railway and that installation of CWR is now being scheduled on existing lines as well as newly-built lines. In general, interaction between CWR and bridge deck takes place on bridge section and additional axial force and displacement is to be developed owing to temperature and braking/acceleration forces. This interaction is known to be mainly governed by span organizations and arrangements of foot bearings. In common practice, movable bearing is stationed and designed on the assumption that it is not able to transfer the horizontal force of upper decks. However, it is well known that horizontal resistance is developed in movable bearings due to friction and that friction coefficient of movable bearing is ranged from 0.03 to 0.20 depending on the material of bearings and magnitude of reactions. Therefore, it is easily reasoned out that friction of movable bearing can influence the mutual behavior of CWR and bridge decks. Suggested in this study is to investigate the validity and efficiency of friction effect of movable bearings in controlling the axial force and displacement of CWR on continuous railway bridges.

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A study on the Stability of Rail way Construction on the Reclaimed Land for Domestic Marine Clay Using the Seismic Analysic (연약지반상 지진하중을 고려한 철도노반의 안정성 검토에 관한 연구)

  • Kim Young-Soo;Kim Moo-Ill
    • Proceedings of the KSR Conference
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    • pp.1071-1076
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    • 2004
  • The purpose. in this study. is to analyze liquefaction potential of Inchon International Airport at the Area Phase ' I ' for Railway Construction of all, seismic response was analyzed using the computer program, Shake91. Four methods proposed by Seed & Idriss. Eurocode, Iwasaki & Tatsuoka. and Ishihara were used for assessment of liquefaction potential and safety factors calculated form these methods are compared. Based on the results of seismic response analysis, the maximum acceleration at the ground surface is larger than that evaluated site factor effect by using site factor because these areas are composed of very loose sand clay. Especially, in the case of analysis with long period earthquake data. it is appeared that the acceleration of earthquake is amplified more largely. Therefore, accurate seismic response analysis is suggested for the design on the important structures on reclaimed land. The analytical results of liquefaction potential show that the increments of N-value and effective overburden pressure with remediation make safety factors increase. Through comparing the safety factors evaluated from four method, the safety factor calculated by See & Idriss method in the lowest one and it is found that the SPT N-value effect the safety factor very largely. And, Iwasaki & Tatsuoka method is affected by various factors such as average grain size. fine contents, confining pressure. In conclusion. to minimize earthquake Risk by liquefaction, the efficient remediation is essential and seismic response analysis should be carride out.

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The Allowable Displacement Limit on the Approach Slab for a Railway Bridge with Ballastless Track (콘크리트궤도부설 교량의 접속슬래브 허용변위한도에 관한 연구)

  • Choi, Jin-Yu;Yang, Shin-Chu;Yoo, Jin-Young;Cho, Hyun-Cheol
    • Proceedings of the KSR Conference
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    • pp.1149-1155
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    • 2007
  • The transition area between a bridge and an earthwork is one of the weakest area of track because of the track geometry deterioration caused unequal settlement of backfill of abutment. In case of a ballastless track, the approach slab is installed to prevent the phenomenon. But, if there is occurred the inclined displacement on the approach slab by a settlement of the foundation or formation, the track is also under the inclined displacement. And this defect causes reducing the running stability of a vehicle, the riding comfort of passengers, and the deteriorations of track by excessive impact subjected to the track. In this study, parametric studies were performed to know what is the allowable displacement limit on the approach slab to avoid such a bad effect. The length and amount of unequal settlement of the approach slab was adopted as parameter for numerical analysis. And car body accelerations, variations of wheel force and rail stress and uplift force induced on a fastener clip are investigated. From the result, resonable settlement limits of an approach slab according to slab length was suggested.

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A Study on Future Container Cranes (차세대 컨테이너크레인에 대한 고찰)

  • Jung Hyun-Soo;Lee Suk-Jae;Hong Keum-Shik
    • Journal of Navigation and Port Research
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    • v.29 no.3
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    • pp.291-298
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    • 2005
  • In this article. the specifications of a future container crane for a 18,000 TEU megaship are investigated After studying the transitions of containerships through the past half century, the characteristics of the past and current container cranes are outlined. together with various research trends throughout the world Upon these results, the size and performance of the container crane that will be used beyond the year 2014 are forecast. Specifically, the structure, trolley and hoist mechanism, control method, outreach. backreach, rail gage, loading capacity, stability, durability, and others are summarized.

Comparison of Chord method with Surveying in Track irregularity Measurement (측량과 현방식 궤도틀림 측정 비교)

  • Lee, Jee-Ha;Lee, Sang-Jin
    • Proceedings of the KSR Conference
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    • pp.1647-1652
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    • 2008
  • Track geometry consists of tangent and curved lines, which caused undesirable changes in initial track geometry by traffic loads. The bigger the changes are, the worse the riding comfort and running stability of train. This is so-called track irregularity and is the most important quality parameters of ballasted track. To be able to objectively assess track irregularity, track geometry should be able to be measured. Practically, railway companies use moving chord method, this method determine versine values via a chord. The versine is the vertical distance to curve measured in the middle of the chord. This type of method measures only versine of track irregularity curve by transfer function from specific property of measuring tool. In this report, review the characteristics of two types of measuring tools by comparing the measurements. The one is GRP-1000 system, optical surveying system with Total station and lazar prism trolly. This calculates track geometry by surveying absolute coordinates of two points each on both rail heads. The other is Trackmaster, measures versine with 2m of chord length.

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Study of the effect of cleaning the intake manifold on common rail diesel engine and exhaust gases (커먼레일 디젤엔진의 흡기 매니폴더 클리닝이 배기가스에 미치는 영향에 관한 연구)

  • Kim, Tae-Jung;Hong, Sung-In
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.10
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    • pp.5912-5918
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    • 2014
  • Owing to highly developed industries and the use of fossil fuels, environmental problems becoming becoming pressing issues globally. Therefore, a study of automobile exhaust is urgently needed. Generally, air is sucked into the engine through the intake manifold. The aims of this study were to reduce the exhaust from used cars and increase the output by removing carbon deposits, which are considered a reason for the increasing exhaust and reduction of output, and the reduction of exhaust, variation of output and stability of idle speed were analyzed. The formation of carbon deposits within the suction manifold was investigated through a test device (KD147). In the intake manifold, the exhaust cleaning effect was confirmed.

Seismic Design of Steel Frame Model Considering the Panel Zone and Viscous Dampers (패널존과 점성감쇠기를 고려한 강골조 구조물의 내진 설계 모델)

  • Park, Sun-Eung;Lee, Tack-Woo
    • Journal of the Korean Association for Spatial Structures
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    • v.20 no.2
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    • pp.87-94
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    • 2020
  • The present study is aimed to calculate the optimal damping according to the seismic load on the structure with a non-seismic design to perform structure analysis considering the deformation of structural joint connection and panel zone; to develop design program equipped with structural stability of the steel frame structures reinforced with the panel zone and viscous dampers, using the results of the analysis, in order to systematically integrate the seismic reinforcement of the non-seismic structures and the analysis and design of steel frame structures. The study results are as follows: When considering the deformation of the panel zone, the deformation has been reduced up to thickness of the panel double plate below twice the flange thickness, which indicates the effect of the double plate thickness on the panel zone, but the deformation showed uniform convergence when the ration is more than twice. The SMRPF system that was applied to this study determines the damping force and displacement by considering the panel zone to the joint connection and calculating the shear each floor for the seismic load at the same time. The result indicates that the competence of the damper is predictable that can secure seismic performance for the structures with non-seismic design without changing the cross-section of the members.

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 High Strength Lattice Girder and Evaluation of Its Performance (고강도 격자지보재의 개발 및 그 성능 평가)

  • Lee, Jae-Won;Min, Kyong-Nam;Jeong, Ji-Wook;Roh, Byoung-Kuk;Lee, Sang-Jin;Ahn, Tae-Bong;Kang, Seong-Seung
    • The Journal of Engineering Geology
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    • v.30 no.1
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    • pp.43-57
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    • 2020
  • The objective of this study was to evaluate the performance of high-strength lattice girders as a possible superior alternative to conventional steel arch ribs. For this purpose, the structural characteristics of supports were analyzed using numerical analysis, and their performance was evaluated using maximum bending load tests and tensile tests of the welded joint. According to the results of structural analysis, the optimum size of the upper and lower members and plates is 50 mm × 31.8 mm × 25.4 mm, demonstrating excellent functionality and economic efficiency. High-strength lattice girders of dimensions 55 mm × 30 mm × 20 mm and 85 mm × 30 mm × 20 mm, determined from bending load tests, are found to meet both the reference values and the target values of H-profiles 100 and 125. A review of the ratio of theoretical deflection to actual deflection shows that the high-strength lattice girder developed during this study meets fewer than five of the evaluation criteria for lattice girder deflections proposed by the Federal Railway Department of Germany. Finally, tensile test results reveal that the welded joint of the high-strength lattice girder at the main steel bar-auxiliary steel bar-plate junction exceeds the target value, indicating that the welded joint has sufficient stability.

A Study on the Behavior of Concrete floors with Over-break in Railroad Tunnel (여굴깊이에 따른 철도터널 바닥 콘크리트의 거동에 관한 연구)

  • Yang, Joo-Kyoung;Kim, Hyo-Jung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.5
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    • pp.101-107
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    • 2017
  • Over-break, which is excavated larger than planned line at tunnel excavation, is inevitable due to the nature of blasting. But regarding the bottom of the foundation, most of the domestic ordering organizations pay only 10 cm thick filled concrete when pouring concrete due to over-break. In accordance, the construction cost will increase greatly if all the depths of the designed over-break are filled only with concrete. When tunnel excavation occurs, concrete filling of 18 MPa(T = 100 mm) and 150 mm~237 mm auxiliary concrete layer and 240 mm concrete track(TCL) are applied to the upper part. The concrete is installed in an excessive amount of about 600 mm between the lower part of the rail and the tunnel rock bed. Therefore, in this study, it is necessary to analyze the concrete crack structure according to the depth of the existing tunnel and the modified tunnel section, and to evaluate the adequacy of the required thickness of the tunnel floor concrete for securing the crack stability of the concrete.