• Title, Summary, Keyword: 슬래브 단부

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The Displacement Limit at the End of an Approach Slab for a Railway Bridge with Ballastless Track (콘크리트궤도 부설 교량의 접속슬래브 단부 처짐한도에 관한 연구)

  • Choi, Jin-Yu;Yang, Shin-Chu
    • Journal of the Korean Society for Railway
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    • v.11 no.2
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    • pp.195-202
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    • 2008
  • 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 could be installed to prevent such a 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 increasing the track deteriorations by excessive impact force acting on the track. In this study, parametric studies were performed to investigate the displacement limit on the approach slab to avoid such problems. The length and the amount of unequal settlement of approach slab were adopted as parameter for numerical analysis considering vehicle-track interaction. Car body accelerations, variations of wheel force, stresses in rail, and uplift forces induced on fastener clip were investigated. From the result, resonable settlement limit on the end of an approach slab according to slab length was suggested.

Curling Behavior of Long-Span Concrete Pavement Slab under Environmental Loads (환경하중에 의한 장스팬 콘크리트 포장 슬래브의 컬링 거동 특성 분석)

  • Kim, Seong-Min;Shim, Jae-Soo;Park, Hee-Beom;Yun, Dong-Ju
    • International Journal of Highway Engineering
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    • v.11 no.3
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    • pp.151-161
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    • 2009
  • This study was conducted to investigate the characteristics of the curling behavior of long-span pavement slabs under environmental loads. By developing and using finite element models of the long-span pavement slabs, the stress distribution and the effects of slab length, slab thickness, stiffness of underlying layers, and the restraints of the slab ends on the curling behavior were analyzed. In addition, the field experiments were performed with the actual long-span pavement slab to obtain the curling behavior of the real structure under environmental loads. As a result of this study, it was found that the vertical displacements of the long-span pavement slab along the centerline due to the curling behavior were zero except for the areas near the slab ends, and the curling stresses were maximum and constant where the displacements were zero. The slab length and the stiffness of underlying layers did not affect the maximum curling stresses. The restraints at the slab ends made the curling stresses occur near the slab ends, but did not much affect the maximum curling stresses.

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Tests for Moment Redistribution in Flat Plates with Different Reinforcement Details according to End and Midspan Moment Distributions (단부 및 중앙부 플랫플레이트의 철근 분배율에 따른 모멘트 재분배 실험)

  • Choi, Jung-Wook;Song, Jin-Kyu
    • Journal of the Korea Concrete Institute
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    • v.19 no.5
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    • pp.603-611
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    • 2007
  • Three interior slab-column connections designed by equal static moments and by different distribution of end and midspan moments were tested. Each test specimen consists of a 4.2 m square slab and a 355 mm square column stub. The slab thickness is 152 mm. Test results showed not only that flat plate systems can undergo considerable redistribution of moments from the uncracked state to final maximum capacity, but also that the distribution of moments is controlled largely by the distribution of reinforcement adopted by the designer. Tests also indicated that the punching shear strength of slabs can be affected by the redistributed moments.

Compressive Strength of Horizontal Joints in Precast Concrete Large Panel System (대형 콘크리트 패널구조 수평접합부의 지지력 성능에 관한 연구)

  • 서수연;정봉오;이원호;이리형
    • Magazine of the Korea Concrete Institute
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    • v.6 no.2
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    • pp.138-147
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    • 1994
  • The compressive strength of horizontal joints in precast concrete large panel structures depends on parameters such as grout and panel strength, detail of joint, joint moment, width of grout column, and etc. 44 specimens were tested to investigate the effects of parameters that influence the compressive strength of horizontal joints. The design formula specified in Korean Cock for compression horizontal joints must be reviewed, because it was based on the test results of the joint types not used in Korea. In this study comparing the test results, there fore, the validity of the design formulas was evaluated and a suitable formula was proposed to predict the ultimate strengths of compression horizontal joints. The increase of ultimate strengths was not observed, even if confined the horizontal displacement of slabs and reinforced the wall edge, when the grout strength is lower than panel strength. From the comparison of test results and those by the proposed formula, it was shown that proposed formula was suitable to predict the ultimate compressive strength of horizontal joints.

A Parametric Study on the Serviceability of Concrete Slab Track on Railway Bridges (철도교 콘크리트 슬래브궤도의 사용성에 관한 매개변수 영향 연구)

  • Park, Hong-Kee;Jang, Seung-Yup;Yang, Sin-Chu;Park, Yong-Gul
    • Journal of the Korean Society for Railway
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    • v.12 no.1
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    • pp.95-103
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    • 2009
  • Deformations of bridge deck ends on abutments and piers bring about severe problems in track geometry and require maintenance work. In case of concrete slab track, more severe deformation and additional forces on rail and rail supports can be induced by bridge deck deformation, which affect the serviceability of track structure since concrete slab track is much stiffer than ballasted track and the behavior of track structure is integrated with that of bridge deck. In this study, the design variables affecting the serviceability of track structure are selected and the influence level is estimated by a parametric study. As a result, it is found that continuous span is advantageous than simply supported span and the stiffness of bridge bearing and rail fastener as well as the distance between last rail support and bridge bearing are most important parameters.

Wheel Load Distribution of Simply Supported Reinforced Concrete Slab Bridge (철근콘크리트 단순 슬래브 교량의 윤하중분포폭에 관한 연구)

  • 오병환;신호상;한승환
    • Magazine of the Korea Concrete Institute
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    • v.10 no.3
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    • pp.125-134
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    • 1998
  • 최근에 수행된 일련의 철근콘크리트 슬래브 교량의 파괴시험의 결과 비록 교량의 노후화되었다 하더라도 내하력은 설계하중보다 더 크게 나타나고 있다. 본 연구에서는 철근콘크리트 슬래브 교량의 이런 높은 내하능력을 보이는 여러 가지 원인들 가운데 가장 큰 영향을 줄 것으로 예상되는 슬래브 교량의 하중분배거동에 대한 연구를 수행하였다. 철근콘크리트 슬래브 교량의 윤하중분포폭에 영향을 미치는 주요 변수들에는 지간길이, 교량폭, 단부보, 하중형태 및 지점조건이 있다. 본 연구결과에 의하면 지간길이와 교폭에 따라 현행의 윤하중분포폭은 과소 혹은 과대 평가되고 있다. 이들 각 변수들에 대한 포괄적인 유한요소 해석과 분석을 통하여 철근콘크리트 슬래브 교량의 윤하중분포폭을 도출하였고 이들 결과들을 비선형 회귀분석을 통하여 슬래브 교량의 윤하중분포폭의 예측 및 설계식을 제안하였다. 본 연구에서 제안된 윤하중분포폭의 식은 철근콘크리트 슬래브 교량의 보다 정확한 설계 및 합리적인 내하력 산정시 매우 효율적으로 사용될 것으로 사료된다.

Experimental Analysis of Terminus and Horizontal Crack Behaviors in Continuously Reinforced Concrete Pavement (연속철근 콘크리트 포장 단부 및 수평균열 거동 실험적 분석)

  • Cho, Young-Kyo;Kim, Seong-Min;An, Zuog;Han, Seung-Hwan
    • International Journal of Highway Engineering
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    • v.13 no.4
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    • pp.81-91
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    • 2011
  • This study was conducted to evaluate the necessity of the anchor lug system in continuously reinforced concrete pavement(CRCP) by comparing longitudinal displacements of CRCPs with and without anchor lugs, and to investigate the effect of horizontal cracking on CRCP performance by measuring the vertical displacements. The measurements before and after the anchor lug section was separated were conducted for 12 days in June, and for 14 days in August after the abrupt displacements according to cutting disappeared, respectively. This short term measurement results showed that when anchor lugs were installed, a daily displacement variation at any location was less than 0.1mm; therefore, longitudinal movements were negligibly small. When there were no anchor lugs, longitudinal displacements mainly occurred near the free end and the displacement variation was small; therefore, an expansion joint system seems to be employed at a CRCP terminus without installing anchor lugs. However, further studies are needed to verify the terminus behavior due to annual temperature changes. The horizontal crack width variation was ignorable and did not affect the vertical displacement of the slab. Therefore, the horizontal crack did not delaminate the slab and did not seem to reduce the structural capacity and performance of CRCP.

Static and Dynamic Behavior at Low-Frequency Range of Floating Slab Track Discretely Supported by Rubber Mounts in Real-Scale Laboratory Test (고무 마운트로 이산 지지되는 플로팅 슬래브 궤도의 실모형 실내 실험에서의 정적 및 저주파 대역 동적 거동)

  • Hwang, Sung Ho;Jang, Seung Yup;Kim, Eun;Park, Jin Chul
    • Journal of the Korean Society for Railway
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    • v.15 no.5
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    • pp.485-497
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    • 2012
  • Recently, with increasing social interests on noise and vibration induced by railway traffic, the application of floating slab track that can efficiently reduce the railway vibration is increasing. In this study, to more accurately understand the dynamic behavior of the floating slab track, a laboratory mock-up test has been performed, and the static and dynamic behaviors at frequency range near the system resonance frequency were explored. Based on the test results, the design of the floating slab track and the structural analysis model used in the design have been verified. The analytic and test results demonstrate that the dominant frequency of the floating slab track occurs at the frequencies between vertical rigid body mode natural frequency and bending mode natural frequency, and the dominant deformation mode is close to the bending mode. This suggests that in the design of the floating slab track, the bending rigidity of the slab and the boundary conditions at slab joints and slab ends should be taken into consideration. Also, the analytic results by the two-dimensional finite element analysis model using Kelvin-Voigt model, such as static and dynamic deflections and force transmissibility, are found in good agreement with the test results, and thus the model used in this study has shown the reliability suitable to be utilized in the design of the floating slab track.

Development of Steel Wire-Integrated Deck Plate Applicable to Slab with 180mm Thickness (두께 180mm 슬래브에 적용 가능한 철선일체형 데크 플레이트 개발)

  • Lee, Yong Jae;Yoon, Sang Chun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.1
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    • pp.89-98
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    • 2012
  • A steel wire-integrated deck plate that welds integrated triangle truss steel wires on a galvanized steel sheet is developed to reduce construction costs of slabs or formworks such as shores and supports, and it is already widely applied in many construction fields. In this research, experimental tests for 14 full scale specimens, which are in the same field conditions, are conducted on several parameters such as the diameter of top, bottom and lattice steel wire, cutting methods of ends. According to the result, changes in final destruction types of the test bodies and cutting methods of ends didn't affect structural performance of test specimens, and for a 4.0m-span test specimen, there was no big problems in using bottom bar D7 or D8.

Development of Precast Slab Track Reinforced with GFRP and Analysis of Behavior (GFRP로 보강된 프리캐스트 슬래브 궤도 개발 및 거동분석)

  • Zi, Goang-Seup;Lee, Seung-Jung;Moon, Do-Young;Kim, Yoo-Bong;Baek, In-Hyuk
    • Proceedings of the KSR Conference
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    • pp.2072-2076
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    • 2011
  • 철도 시스템에서 철도궤도와 레일은 주요한 신호 시스템의 일부로 사용되고 있으나 콘크리트 슬래브 궤도 내부의 철근으로 인한 신호전류 감소, 교란 등을 방지하기 위해 과도한 절연작업이 필요하다. 본 연구에서는 국내에서 기 개발된 프리캐스트 슬래브 궤도의 횡방향 철근을 GFRP 보강근으로 대체하여 절연작업의 감소를 가능하게 하였다. GFRP로 보강된 프리캐스트 슬래브 궤도의 설계과정과 정적 휨 시험과 단부의 연결철근 인발 시험을 통한 거동 분석 및 고찰 내용을 제시하였다. 휨 시험과 실스케일 인발 시험의 결과 정적 휨 강도는 정립된 설계법에 의해 적절한 강도를 가지고 있으나 기 개발된 연결철근의 위치와 형태는 온도 또는 수축으로 인해 발생할 수 있는 축력을 저항할 수 없음을 확인하였다.

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