• Title, Summary, Keyword: Railway bridge abutment

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Comparison of Construction Cost and External Stability of Railway Abutment wall with Friction Angle of Backfill Materials (뒷채움재의 내부마찰각 변화에 따른 철도교대의 안정성 및 공사비 비교)

  • Yoo, Chunghyun;Choi, Chanyong;Yang, Sangbeom;Park, Yonggul
    • Journal of the Korean Geosynthetics Society
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    • v.15 no.3
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    • pp.67-76
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    • 2016
  • The railway bridge abutment subjected to the lateral earth pressure is a sensitive structure that is affected by backfill materials, installation methods, compaction, and drainage system and so on. The several design loads for the bridge abutment design consist of traffic loading on bridges and vertical & lateral force due to surcharge load at backfill. Especially, the lateral earth pressure of design load components is important and considered in the design of geotechnical engineering structure such as bridge abutment wall. The determination of cross section for abutment is finally determined with calculating external stability and member force of abutment wall structures. In this study, the abutment wall height is 12m and the optimal cross section of abutment wall has been determined that satisfies an external stability for abutment structure through friction angles of 35, 40, and 45 degrees of backfill materials. The external stability and member force of abutment wall with friction angle of backfill materials and were calculated and construction cost of each abutment wall structures was compared. It found that the construction cost was reduced from 2.2 to 8.4% with friction angle of backfill materials.

A Correlation Analysis on Earth Pressure and Subgrade Stiffness in Bridge Abutment Transition Zone (철도 교량접속부의 토압과 노반강도와의 상관관계)

  • Kim, Jin-Hwan;Cho, Kook-Hwan
    • Journal of the Korean Society for Railway
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    • v.19 no.5
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    • pp.647-655
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    • 2016
  • The construction of high speed railways and improvement projects of for conventional railways require straight railway lines of railway, which leads to an increase of bridge and tunnel construction. Transition zones in railways means that the track support stiffness is variedvaries in over short ranges. Sspecial attention is required in theose transition zones since because instability of train running in train and irregularities of track irregularities are can frequently occurred. Typical transition zones are between bridges and earthworks and between tunnels and earthworks. On In a transition zone, a bridge abutment transition zone has many problems in with various causes. In this paper, fundamental problems of bridge abutment transition zones is are analyzed to enhance the understanding about of bridge abutment transition zones. Suggestions for improving problems in the transition zones are proposed.

Numerical analysis on stability of express railway tunnel portal

  • Zhou, Xiaojun;Hu, Hongyun;Jiang, Bo;Zhou, Yuefeng;Zhu, Yong
    • Structural Engineering and Mechanics
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    • v.57 no.1
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    • pp.1-20
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    • 2016
  • On the basis of the geological conditions of high and steep mountainous slope on which an exit portal of an express railway tunnel with a bridge-tunnel combination is to be built, the composite structure of the exit portal with a bridge abutment of the bridge-tunnel combination is presented and the stability of the slope on which the express railway portal is to be built is analyzed using three dimensional (3D) numerical simulation in the paper. Comparison of the practicability for the reinforcement of slope with in-situ bored piles and diaphragm walls are performed so as to enhance the stability of the high and steep slope. The safety factor of the slope due to rockmass excavation both inside the exit portal and beneath the bridge abutment of the bridge-tunnel combination has been also derived using strength reduction technique. The obtained results show that post tunnel portal is a preferred structure to fit high and steep slope, and the surrounding rock around the exit portal of the tunnel on the high and steep mountainous slope remains stable when rockmass is excavated both from the inside of the exit portal and underneath the bridge abutment after the slope is reinforced with both bored piles and diaphragm walls. The stability of the high and steep slope is principally dominated by the shear stress state of the rockmass at the toe of the slope; the procedure of excavating rockmass in the foundation pit of the bridge abutment does not obviously affect the slope stability. In-situ bored piles are more effective in controlling the deformation of the abutment foundation pit in comparison with diaphragm walls and are used as a preferred retaining structure to uphold the stability of slope in respect of the lesser time, easier procedure and lower cost in the construction of the exit portal with bridge-tunnel combination on the high and steep mountainous slope. The results obtained from the numerical analysis in the paper can be used to guide the structural design and construction of express railway tunnel portal with bridge-tunnel combination on high and abrupt mountainous slope under similar situations.

Experimental Study on Characteristics of Deformation for Concrete Track on Railway Bridge Deck End induced by Bridge End Rotation (철도교량 단부 회전에 따른 콘크리트 궤도의 변형특성에 관한 실험적 연구)

  • Lim, Jongil;Song, Sunok;Choi, Jungyoul;Park, Yonggul
    • Journal of the Korean Society for Railway
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    • v.16 no.3
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    • pp.217-225
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    • 2013
  • In this study, by considering the rail fastening support distance and the distance between the bridge and the abutment, the behavior of concrete track installed on a railway bridge end deck and the bridge end rotation were analyzed. In order to analyze the track-bridge interaction, bridge and abutment specimens with concrete track structures were designed and used in laboratory testing. At a constant fastening support distance, an increase in the bridge end rotation caused an increase in the displacement of the rail. Therefore, the displacement of the rail directly affects the rail and clip stress. Further, it is inferred that the results of multiple regression analysis obtained using measured data such as angle of bridge end rotation and fastening support distance can be used to predict the track-bridge interaction forces acting on concrete track installed on railway bridge deck ends.

Stability of Railway Bridge Abutment with Earth Pressure and Internal Friction Angle of Backfill (내부마찰각과 토압 산정방법에 따른 철도교대의 안정성 비교 연구)

  • Choi, Chan Yong;Kim, Hun Ki;Yang, Sang Beom;Kim, Byung Il
    • Journal of the Korean Society for Railway
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    • v.19 no.6
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    • pp.765-776
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    • 2016
  • In this study, a standard section of a railway bridge abutment wall was designed to satisfy the external stability condition in accordance with the design criteria; this design was used to compare and analyze the active earth pressure and to calculate various types of earth pressure acting on the virtual back (wall, plane) according to the frictional angle of the backfill materials. Also, the external stability, member force and construction cost were analyzed according to the frictional angle of the backfill materials using various theories of earth pressure such as Rankine, Coulomb, Trial Wedge, and Improved Trial Wedge. As for the results, it was found that lateral earth pressure at the virtual back plane was higher than at the virtual back wall, and that these values decreased with the increase of the frictional angle of the backfill materials. The increasing of the frictional angle of the backfill materials decreased the active earth pressure (according to Rankine, Coulomb, Trial Wedge, and Improved Trial Wedge results), and the member force as well as the construction cost were reduced.

Comparison of Performance with Backfill Inclination Slope and Shape in Railway Abutment and Transitional Zone Using Centrifuge Model Tester (원심모형실험기를 이용한 철도 교대접속부 배면 기울기 및 형상에 따른 성능비교)

  • Choi, Chan-Yong;Kim, Hun-Ki;Park, Jung-Hyun
    • Journal of the Korean Geosynthetics Society
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    • v.17 no.1
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    • pp.85-93
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    • 2018
  • A existing standard design section of transitional zone between bridge and earthwork section in high speed railway should be designed to gradually change support stiffness from bridge abutment to backfill side that were placed on cemented stabilized gravel, general gravel, soil materials. The larger the backfill slope of the general gravel and soil was more structurally stable, but there is no clear reason about them. In this study, it was compared with settlement and bearing capacity of backfill area in currently design and alternating backfill slope section using large centrifuge tester. As the experimental results, it was showed that the 1:2 slope and 1:1.5 slope have almost similar bearing capacity behavior under the load stage as railway loading level.

The Parameter Study of Serviceability Review of End Track on Railway Bridge installed Concrete Slab Track (콘크리트궤도 부설 교량의 단부 사용성 검토를 위한 매개변수 연구)

  • Sung, Deok-Yong;Kim, Young-Ha;Park, Yong-Gul;Kim, Sung-Il
    • Proceedings of the KSR Conference
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    • pp.117-124
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    • 2008
  • Construction of concrete slab track is trending to increase gradually in national and international for reduction in track maintenance cost and secure of ride comfort. However, in case of railway bridge installed concrete slab track, the serviceability review of end deck should be performed for reducing the maintenance cost of track. The serviceability review of track contains that the compression force which is occurred on fastener of end bridge should be smaller than the compression force causing the deformation limit of elastic pad and the uplift force which is occurred on fastener of end abutment should be smaller than initial fastening force. Therefore, this study calculated the deflection and end rotation of the railway bridge according to the span length and stiffness of railway bridge and estimated the compression force and uplift force which are occurred on the track of end bridge using the finite element method. This study indicated the several diagrams that are contained the correlation between the behaviour of the track and the behaviour of the railway bridge. As a result, to reduce the end rotation of the railway bridge is very efficient to increase the height of railway deck.

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Behavior of Fastening system of HSR bridge ends deck on Slab Track installed Bridge (슬래브궤도가 부설된 고속철도 교량단부 체결장치의 거동)

  • Chun, Dae-Sung;Choi, Jung-Youl;An, Hea-Young;Park, Yong-Gul
    • Proceedings of the KSR Conference
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    • pp.1637-1646
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    • 2008
  • Deformations of bridge deck ends on abutment can cause extreme deformations on track. Especially, since slab track was fixed onto the bridge deck slab on concrete slab track installed bridges, deformations of bridge deck ends directly affect the slab track behavior, and thus these interactions can bring about the premature failure of rail fastenings or other deteriorations to lower the serviceability. In this study, a foreign standard to evaluate forces on track components caused by the track-bridge interactions and the behavior of bridge deck ends was investigated and for real scale bridges. It was found that rail support spring coefficients, as well as toe loads, support spacing were very important parameters.

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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 the Supportive Stiffness in Transitional Zones through Moving Load-Based Three-Dimensional Modeling (이동하중과 3차원 모델링을 통한 접속부 지지강성연구)

  • Woo, Hyeun-Joon;Lee, Seung-Ju;Kang, Yun-Suk;Cho, Kook-Hwan
    • Proceedings of the KSR Conference
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    • pp.1542-1549
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    • 2011
  • The Transitional zone between bridge abutment and earthwork is one of the representative vulnerable zones in railway where differential settlements may take place due to the different supportive stiffness. Although transitional zones are managed with stricter standards than those of the other earthwork zones either in the design and construction stages, it is very difficult to prevent differential settlement perfectly. A three-dimensional numerical analyses were performed by applying train moving load in this study. The analytical model including abutments and earthwork zones was constituted with rail, sleepers, track concrete layer (TCL), hydraulic stabilized base (HSB), reinforced road bed, and road bed using railway and road base structure. The clamp connecting the rail and sleeper were also modeled as the element with spring coefficient. The train wheel is modeled in the actual size and moved on the rail with 300 km/hr speed. The deformation characteristics at each point of the rail and the ground were considered in detail when moving the train wheel. The analysis results were compared with those from the two-dimensional analysis without considering moving load. The research results show that displacement and stress were greater in the three-dimensional analysis than in other analyses, and the three-dimensional analysis with moving load should be performed to evaluate railway performance.

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