• Title, Summary, Keyword: 교량단부 변형

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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.

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.

Evaluation of Uplift Forces Acting on Fastening Systems at the Bridge Deck End Considering Nonlinear Behaviors of the Fastening Systems (체결장치 비선형 거동을 고려한 교량 단부에서의 체결장치 압상력 평가)

  • Yang, Sin Chu;Kim, Hak Hyung;Kong, Jung Sik
    • Journal of the Korean Society for Railway
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    • v.20 no.4
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    • pp.521-528
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    • 2017
  • In this study, vertical loading tests were conducted to investigate the nonlinear behaviors of the fastening systems that have generally been used in the concrete track of domestic railway lines. Nonlinear load-displacement curve models were derived based on the test results. The uplift forces generated in the fastening systems were evaluated by applying the derived nonlinear models as well as the existing linear models. The influence of the factors on the maximum uplift force of the fastening system was analyzed through a parameter study on the distance between neighboring sleepers, the horizontal distance between the center of the bearing and the nearest fastening system from the deck end, and the height of the bridge girder. From the evaluation results it is known that, for economical track and bridge design, due to deck end deformation, it is necessary to consider the nonlinear behavior of the fastening system in the calculation of the uplift force of the fastening systems.

Fatigue Evaluation of a Steel Bridge in Service through Stress History Measurement and Consideration of Stress Category (공용중인 교량의 응력이력 계측 및 응력범주를 고려한 피로평가)

  • Na, Sung-Ok;Kwon, Min-Ho;Cha, Cheol-Jun;Kim, In-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.2
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    • pp.108-116
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    • 2014
  • The proper stress history measurement should be conducted in order to examine the accurate cause of fatigue cracks or the fatigue safety in the steel bridge. Only one strain gauge is generally installed in the field for the stress history examination because of the field circumstances, economic feasibility, workability, and so on. However, this method may not consider the actual size of the specific structure, the gauge length, and the affect of stress concentration in the welded joint. In addition, it is difficult to apply for the stress analysis. Therefore, this study suggests improvements that are a great number of gauge installations, the gauge location adjustment, and the use of the minimum length gauge. It is drived the correlative equation of strain for the distance between the welding toe and the strain gauge installation, and compare correlative equation with equation of IIW. Also, this study could estimate the remaining life and fatigue damage of bridge in service by selecting the suitable stress category. In conclusion, it is possible to understand the member which is high in the fatigue cracks, and the quantitative relations between the welding toe and the strain gauge installation distances. The proposed approach in this study can make an more accurate fatigue damage and a remaining life prediction so that the improved method should be applied in measuring the strain of bridges from now on.

Dynamic Performance Evaluation of New Type PSC Railroad Bridges (신형식 PSC 철도교량의 동적성능 평가)

  • Choi, Sanghyun
    • Journal of the Society of Disaster Information
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    • v.7 no.4
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    • pp.259-265
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    • 2011
  • After the commercial opening of the KTX in 2005, the high speed railroad has been rapidly emerged as the major transportation means due to its high energy efficiency. Recently, the government has announced its plan to build the future transportation system around the high speed railroad. Based on this policy, the existing lines as well as the lines under construction or design are planning to increase design speed. In this paper, the suitability of the mid-span PSC girder bridges for the high speed railroad is evaluated via dynamic analysis. IT, Precom, and WPC girder bridges are considered for the purpose of this study and, for comparison, the identical modeling method and the analysis technique are utilized. The performance indices used for dynamic performance evaluation are the natural frequency, the vertical displacement, the end axial displacement, track irregularity, etc. The KTX train is utilized as a dynamic load, and the dynamic analysis is performed up to the train speed of 420km/hr with the increment of 10km/hr.

Parametric Study on Steel composite Girder bridges for HONAM High-Speed Railway Considering Criteria Requirement of Dynamic Response (호남고속철도 동적 안정성 요구 조건을 고려한 강합성 거더교의 변수 연구)

  • Cho, Sun-Kyu;Jung, Han-Ouk;Kim, Sung-Il
    • Proceedings of the KSR Conference
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    • pp.1370-1378
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    • 2007
  • High speed railway bridge is affected on safety of bridge by dynamic amplification effect, when dynamic response of bridge is equal to effect cycle load for rolling stock axle according to high speed operation train. And excessive deformation of structure has negative effect on operation safety of train and comfort of passenger due to fluctuation of wheel load by torsion of track etc. and decrease of contact force on vehicle wheel-rail. To ensure the safety of track and train operation safety, it is have to perform the study on resonance and deformation of structure. That criteria and requirement of railway bridge is limitation of vertical acceleration on deck for dynamic behavior of structure, contact of vehicle wheel and rail, limitation of face distortion and rotation angle of end deck, and limitation of vertical displacement by train. Unlike KYEONGBU High Speed Railway, New constructed HONAM High Speed Railway have to applied the new requirement for dynamic behavior safety according to change of condition which is type of ballast (slab ballast), interval of track, and actual rolling stock load. Therefore, in this paper, it was conformed the dynamic characteristic due to parameter, which related with above mentioned criteria, for steel composite bridges.

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Dynamic Behavior of Pretensioned Concrete Member during Detensioning (긴장재 절단에 따른 프리텐션 부재의 동적 거동 고찰)

  • Kim, Jangho;Mun, Do Young;Ji, Goangseup;Kim, Gyuseon
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.5A
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    • pp.747-756
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    • 2008
  • The purpose of this paper is to investigate the effect of the important parameters on the transfer length during the dynamic flame cutting of tendon experimentally. The considered parameters were strand diameter, concrete cover thickness, stirrup, debonding strand and release method. Ten pretensioned concete beam specimens were cast and tested. Time history curves for the axial strain of tendon were measured by electrical resistance strain gauges mounted on the strands. Experimental results indicated that large dynamic shock effects occurred near cut-end during the sudden release. The prestressing forces are dependent on the parameters above considered. The ratio of residual prestressing forces of 12.7 mm strands is greater than 15.2 mm strands. Using debonding strand and gradual release are more efficient for applying prestressing forces.

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Experimental Study on the Static Behavior of the Spliced PSC Box Girder (분절 PSC 박스거더의 정적거동에 관한 실험적 연구)

  • Chung, Won-Seok;Kim, Jae-Hueng;Chung, Dae-Ki
    • Journal of the Korea Concrete Institute
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    • v.19 no.4
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    • pp.433-439
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    • 2007
  • The main objective of the paper is to investigate the static behavior of a prestressed concrete (PSC) girder that has been spliced with precast box segments. A 20 m long full-scale spliced PSC girder is fabricated and tested to compare its static performance against a monolithic girder. The monolithic girder has the same geometric and material properties with respect to the spliced girder. This includes infernal strain, deflections, neutral axis position, and crack patterns for both girders. The test also consists of monitoring relative displacements occurring across the joints. Both the horizontal displacement (gap) and vertical displacement (sliding) are measured throughout the loading procedure. All results have been compared to those obtained from the monolithic girder. It has been demonstrated that the spliced girder offers close behavior with respect to the monolithic girder up to the crack load. Both girders exhibits ductile flexural failure rather than abrupt shear failure at joints.

An Experimental Study on the Behavior of the Perforated Rib Connector with Shearing Bars (전단구속철근을 배치한 유공강판 전단연결재에 관한 실험적 연구)

  • Kim, Sung-Chil;Kim, Young-Ho;Yu, Sung-Kun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.6
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    • pp.175-182
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    • 2006
  • In the design of composite structures, shear connectors such as headed stud, channel, perforated plate, etc, are commonly used to transfer longitudinal shear forces across the steel-concrete interface. Many researches have been conducted to improve the characteristics of different types of shear connector. This paper presents the results of 11 push-out tests performed on the new perforated rib connectors with shearing bars embedded in concrete slab under static loads. The results obtained from these tests are as following : 1) The bearing plate welded on both sides of perforated rib plate improves the stiffness and strength. 2) The capacity of perforated connectors is influenced primarily by the transverse reinforcements and shearing bars.