• Title, Summary, Keyword: 철도교대

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Economic Evaluation on Geosynthetic Reinforced Abutment for Railways (토목섬유로 보강된 철도교대의 경제성 평가)

  • Kim, Dae Sang;Kim, Ung-Jin;Sung, Keun-Yeol;Kim, Hak-Mo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.9
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    • pp.508-517
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    • 2018
  • This study evaluated the construction costs of 11 design cases to decrease the horizontal forces applied to an abutment. They include two kinds of abutment types, which are used to improve the backfill materials for reversed T-shaped abutment and geosynthehtic reinforced abutment for railways (RAR). In the first economic analysis, the internal friction angles of the backfill materials were increased from ${\Phi}=35^{\circ}$ to ${\Phi}=40^{\circ}$ and $50^{\circ}$ for a reversed T-shaped abutment. The second analysis examined cases with the design of a geosynthehtic RAR. When the friction angles were $40^{\circ}$ or $50^{\circ}$ after improvement of the backfill material, the reduction in the construction cost of the abutment was not as large (2.0-3.9%), even though the horizontal forces on the abutment were decreased by 18-48%. However, in the case of applying the RAR, a maximum cost reduction of 30% was achieved by decreasing the horizontal force to zero. The cost reduction results from the decreased wall thickness, base slab size, and the number of pile foundations for the abutment, as well as changing the material.

A study on Response Characteristics for the Reinforced Abutment for Railroads by Numerical Analyses (수치해석을 통한 철도보강교대의 응답 특성 연구)

  • Kim, Dae-Sang;Jeong, Rag-Gyo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7949-7956
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    • 2015
  • This paper introduced the RAR(Reinforced Abutment for Railroads) to reduce settlement of transitional zone and horizontal displacement of abutment by constructing backfill before abutment. We expect that it has more economical and better performance which was validated by numerical analyses. First, transitional zone settlements and horizontal displacements of existing abutment were evaluated for various heights and ground conditions by using finite element analysis program. Then, numerical analyses of it under the same conditions were performed and its results were compared with existing abutment's ones. From the numerical analysis, we found that the responses(settlement and horizontal displacement) of transitional zone of the RAR is about 20% and 34% of one of existing abutment due to the effect of backfill stabilizing. We expected that the RAR having small foundations could be economic way to construct abutment with the control of responses such as, settlement, horizontal displacement, and earth pressure.

Economic Evaluation on Geosynthetic Reinforced Abutment for Railways (특정형상의 인공자갈이 혼합된 도상자갈층의 지지성능과 응력전달특성)

  • Kim, Dae Sang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.15-20
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    • 2019
  • This paper evaluated the construction costs of 11 design cases to decrease the horizontal forces applied to the abutment. They include two abutment types, which are to improve backfill materials for a reversed T-shaped abutment and geosynthetic Reinforced Abutment for Railways (RAR). The first type of economic analysis was that the internal friction angles of backfill materials were increased from Φ=35° to Φ=40° and 50° for a reversed T-shaped abutment. In addition, the second type was the cases with the design of geosynthetic RAR. When friction angles of 40° or 50° were applied through the improvement of the backfill material, the decrease in construction cost of the abutment was not large (2.0~3.9%), even though the horizontal forces applied to the abutment had decreased to 18~48%. In the case of applying the RAR, however, a maximum 30% cost reduction was evaluated by the decrease in horizontal force to "0" theoretically. The cost reduction resulted from the decrease in wall thickness, base slab size, and number and material change of pile foundation for the abutment.

Evaluation of Behaviors in Abutment Transition Zone Depending on Constrution Orders and Number of Piles (뒤채움 시공순서 및 말뚝 수에 따른 교대 접속부 거동평가)

  • Kim, Ung-Jin;Jeong, Rag-Gyo;Kim, Dae-Sang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.1
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    • pp.1-7
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    • 2017
  • The RAR (Reinforced Abutment for Railways) is an economical abutment to reduce the settlement of a transitional zone and horizontal displacement of an abutment by constructing backfill before the abutment. In this paper, the performance of the RAR depending on the pile installation was evaluated using 2D (Dimensional) finite element analysis and compared with the existing abutment (with 5 rows pile). Numerical analysis showed that increasing pile installation is more effective in reducing horizontal displacement and earth pressure than settlement of the transitional zone. The horizontal displacement and earth pressure of the RAR was approximately 26~37% and 59~83% compared to the existing abutment by changing the pile installation. More pile installation led to a greater reduction of the horizontal displacement and earth pressure of the RAR. In addition, the horizontal earth pressure of RAR is influenced considerably by the reinforcement, pile, foundation, and stiffness of the ground.

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.

Analysis of Settlement Characteristics and Strength of Cement Mixing Ratio for a Backfill Material at a Railway Abutment (철도교대 뒤채움재료의 시멘트 혼합 비율에 따른 강도 및 침하특성 분석)

  • Yang, Sang-Beom;Choi, Chan-Yong;Kim, Nak-Kyung;Kim, Tae-Kyun
    • Journal of the Korean Geotechnical Society
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    • v.32 no.9
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    • pp.29-36
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    • 2016
  • Backfill materials of rail abutment were commonly composed with cement treated aggregate, general aggregate and soil. The friction angle of cement treated aggregate increased up to $40^{\circ}$ or more due to strength enhancement. However, $30^{\circ}{\sim}35^{\circ}$ of friction angle was typically applied for in-situ condition. This phenomenon could cause over-designing, therefore, it is essential to determine reasonable material properties of cemented treated aggregate. In this study, a series of CBR tests and circular model tests have been conducted for cement treated aggregate, while changing cement mixing ratio. Based on test results, characteristics of settlement and strength have been analyzed quantitatively. The settlement of cement treated aggregate decreased with the number of cyclic loading and aging period. In addition, The strength increment ratio in CBR test increased up to 13~16 times at 28 days aging.

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.

An Experimental Study on the Girder-Abutment Connection for the Steel-Concrete Composite Rigid-Frame Bridge Integrated with PS Bars (PS 강봉으로 일체화된 강합성 라멘교의 거더-교대 접합부의 거동에 관한 실험적 연구)

  • Lee, Sang-Yoon;Ahn, Young-Soo;Oh, Min-Ho;Chung, Jee-Seung;Yang, Sung-Don
    • Journal of the Korea Concrete Institute
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    • v.24 no.4
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    • pp.453-463
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    • 2012
  • Steel-concrete composite rigid-frame bridge is a type of integral bridge having advantages in bridge maintenance and structural efficiency from eliminating expansion joints and bridge supports, the main problems in bridge maintenance. The typical steel-concrete composite rigid-frame bridge has the girder-abutment connection where a part of its steel girder is embedded in abutment for integrity. However, the detail of typical girder-abutment connection is complex and increases the construction cost, especially when a part of steel girder is embedded. Recently, a new type of bridge was proposed to compensate for the disadvantages of complex details and cost increase. The compensation are expected to improve efficiency of construction by simplifying the construction detail of the girder-abutment connection. In this study, a static load test has been carried out to examine the behavior of the girder-abutment connection using real-scale specimens. The results of the test showed that the girder-abutment connection of proposed girder bridge has sufficient flexural capacity and rebars to control concrete crack should be placed on the top of abutment.