• Title/Summary/Keyword: Railway bridge

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Verification Study of Train/Bridge Interaction Analysis through Field Tests of a High Speed Railway Bridge (고속철도 교량의 속도별 주행시험을 통한 교량/열차 상호작용해석의 검증)

  • Kim, Sung-Il;Lee, Joo-Beom;Kim, Hyun-Min;Lee, Hee-Up
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1555-1561
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    • 2011
  • The dynamic behavior of a bridge under moving loads has been investigated over many years. Especially, with the introduction of High Speed Railway, numerous theoretical studies on the interaction problem between bridges and trains are carried out. In the present study, advanced bridge/train interaction analyses are performed and compared with field tests of a simply-supported 40m long PSC box girder bridge of Kyung-Bu High Speed Railway. Vertical displacements and vertical accelerations of a bridge with increasing speeds are analyzed. In addition, wheel load reduction rates and accelerations of a car-body of the train are investigated for a study of appropriateness of traffic safety criteria of bridge design specification.

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Nondestructive Evaluation of Railway Bridge by System Identification Using Field Vibration Measurement

  • Ho, Duc-Duy;Hong, Dong-Soo;Kim, Jeong-Tae
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.6
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    • pp.527-538
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    • 2010
  • This paper presents a nondestructive evaluation approach for system identification (SID) of real railway bridges using field vibration test results. First, a multi-phase SID scheme designed on the basis of eigenvalue sensitivity concept is presented. Next, the proposed multi-phase approach is evaluated from field vibration tests on a real railway bridge (Wondongcheon bridge) located in Yangsan, Korea. On the steel girder bridge, a few natural frequencies and mode shapes are experimentally measured under the ambient vibration condition. The corresponding modal parameters are numerically calculated from a three-dimensional finite element (FE) model established for the target bridge. Eigenvalue sensitivities are analyzed for potential model-updating parameters of the FE model. Then, structural subsystems are identified phase-by-phase using the proposed model-updating procedure. Based on model-updating results, a baseline model and a nondestructive evaluation of test bridge are identified.

Evaluation of the Status of Ballast on the Bridge Expansion f)int using HWAW method (HWAW방법을 이용한 고속철도 교량 상판 신축 이음부 도상 자갈의 이완상태 및 이완범위 평가)

  • Park, Hyung-Choon;Park, Jun-O;Jin, Nam-Hee;Noh, Hee-Kwan;Bae, Hyun-Jung
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.997-1002
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    • 2009
  • The local loosening of ballast supporting railway tract cause a differential vertical tract settlement. In the bridge, the temperature change make bridge deck to contract and expand, and this movement cause local loosening of ballast on the bridge expansion joint. Therefore, the evaluation of the status of ballast on the bridge expansion joint is important for the track maintenance of the high-speed railway. In this paper, hwaw method was applied to evaluate the status of ballast on the bridge expansion joint. HWAW method is non-destructive test to evaluate 2-D shear wave velocity map along the railway. Shear wave velocity is directly related with status of ballast. In this research, hwaw method was applied two different types of bridges and determine the degree and the range of the ballast loosening caused by movement of the bridge expansion joint.

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A Study on the Effects of a High-Speed Railway Bridge Vibration induced by Moving Train on the Adjacent Bridge (열차주행에 의한 고속철도 교량의 진동이 인접 교량에 미치는 영향에 관한 연구)

  • Kim Sung-Il;Lee Jang-Seok
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.900-905
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    • 2004
  • A study on the effects of a high-speed railway bridge vibration induced by moving train on the nearby bridge is performed. Longitudinal and lateral accelerations of slabs and piers which are calculated from moving load analysis of a high-speed railway bridge can be used as input ground motions for the adjacent bridge. Dynamic responses of the adjacent bridge considering soil-structure interaction effects are analyzed by sub-structure method. Analysis procedure is made of free field analysis, calculation of impedance and effective input load and soil-structure system analysis.

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Comparison of Girder Height and Construction Cost by Span in Various Types of Railway Bridge (철도교량형식의 경간에 따른 형고 및 공사비 비교연구)

  • Lee, Tae-Gyu;Oa, Seong-Wook
    • Journal of the Korean Society for Railway
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    • v.11 no.5
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    • pp.471-476
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    • 2008
  • The superstructure type of the railway bridge in our country, is mainly classified into the box girder and the I-type girder. The box girder is widely used in the high speed railway bridge because of the safety due to dynamic behavior. The I-type girder is used in the conventional railway bridge, and is also divided into the general type and the composite type, and the newly modified types have been developed. According to the current railway bridge design code, the girder design by the span length in various types of railway bridge is performed in is study. The suitable girder height and the construction cost by the span length are analyzed, and the comparative analysis of the structural efficiency and the economical efficiency is carried out. From this study, the composite type girder is appeared the good result in respect of the structural efficiency. However, in the economical aspect, the general I-type girder is required less cost than the other types.

Estimation of Stiffness Limit for Railway Bridge Vibration Serviceability (진동사용성을 고려한 철도교량구조물의 강성한계 분석)

  • Jeon, Bub-Gyu;Kim, Nam-Sik;Kim, Sung-Il
    • Journal of the Korean Society for Railway
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    • v.11 no.5
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    • pp.489-498
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    • 2008
  • In general, deflection limit criteria of bridge design specifications have been considered based on static serviceability and structural stability. Dynamic serviceability induced from bridge vibration actually has not been included in the criteria. Thus, it is necessary for deflection limit to be considered in order to check dynamic service- ability on bridge vibration. In this study, The allowable displacement of Korea Railway Bridge Design Specifications is compared to the frequency domain comfort limit and analyzed france code and japanese code. Korea Railway Bridge Design Specifications is regulated based on the train speed. Such is because the vibration time duration is partly considered. but this criteria is not satisfied with comfort limit. and, it is estimated to be capable to provide deflection limit considering dynamic serviceability. In order to evaluate the dynamic serviceability of various types of railway bridges in current public were selected and their dynamic signals were measured. and the result of the bridge-train interaction analysis according to the changes in bridge stiffness was compared to the comfort limit to suggest the stiff-ness limit to the dynamic serviceability, which should conveniently be applied at the field.

A study of the rail and bridge stability according to rail conditions on the bridge (교량상 레일 조건에 따른 레일 및 교량의 안전성 연구)

  • Min, Kyung-Ju;Kim, Young-Kook;Woo, Yong-Keun
    • Proceedings of the KSR Conference
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    • 2009.05a
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    • pp.505-515
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    • 2009
  • In railway bridges, various loads including train load, transverse load and braking force are applied to continuous CWR or semi-continuous longer rail located on non-continuous bridge superstructures. The rail-girder interaction due to thermal expansion is also very complex in railway bridges because the thermal characteristics for each of the rails and girder are quite different. Recently, the bridge retrofits for seismic loads were performed on bridges not designed for these loads. These retrofits may however have limitations with respect to rail-girder interactions because, in general these retrofits address issues related only to seismic loads. In this study of seismic evaluations for railway bridges, the load effects on the bridge rails from the road beds through the continuous rails shall be considered. Practical methods will be proposed which will increase the railway stability. For this, rail-girder interaction analyses due to train loads, temperature changes and seismic loads were performed and the results reviewed from a practical point of view.

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Deflection Limit based on Vibration Serviceability of Railway Bridges Considering the Correlation between Train Speed and Vertical Acceleration on Coach (열차의 주행속도와 차체연직가속도의 상관관계를 고려한 철도교량의 진동사용성 처짐 한계)

  • Jeon, Bub-Gyu;Kim, Nam-Sik;Kim, Sung-Il
    • Journal of the Korean Society for Railway
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    • v.14 no.6
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    • pp.545-554
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    • 2011
  • In order to get dynamic serviceability of a train travelling on a railway bridge, comfort limits with the deflection of bridge and vertical acceleration on car body are proposed in Eurocode, Shinkansen design criteria, The design guideline of the Honam High-speed railway. The design guideline of the Honam High-speed railway has quoted Eurocode. Therefore it is expected that supplementation of comfort limit of railway bridge according to expansion of span length and the improvement traveling speed of trains in the future would relatively fall behind developed countries in railway. Therefore, in order to secure technological competitiveness in world market, the study was conducted to propose the deflection limit based on vibration serviceability of railway bridges that can consider bridge-train interaction and travelling speed increase. The parameter study and bridge-train dynamic interaction analysis was conducted to figure out the correlation of vertical acceleration on car body and bridge displacement according to the increase in travelling speed. Also, the trend of increasing vertical acceleration on car body according to the increase in travelling speed was confirmed, and the amplification coefficient of vertical acceleration on car body was suggested. And the deflection form and vibration of the bridge were assumed to be in harmonic motion, and transfer function and the amplification coefficient were used to develop the dynamic serviceability deflection limit of the high-speed railway bridge as a formula.

Back-Calculated P-y curves from Lateral Load Tests for Railway Bridge Foundation (수평재하시험을 이용한 철도교 기초의 P-y 곡선에 관한 연구)

  • Kim, Jong-Chil;SaKong, Myung;Cho, Kook-Hwan
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.821-828
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    • 2011
  • A significantly larger lateral load and moment are applied on a high speed railway bridge foundation than other bridge foundations. Therefore most of bridge foundations on Honam high speed railway project were designed by high strength steel pipe piles to resist lateral load and moment, which caused the increase of construction costs. In order to perform optimum design, it is important to estimate accurate lateral resistance when designing this type of structure. Lateral load tests were carried out based on the field design data with the purpose of examining the lateral behavioral characteristics of a railway bridge foundation. The standard load test method(ASTM D 3966) was used for field tests by applying twice of design load. Total four load tests were performed on high speed railway bridge foundations with strain gages installed by every 1m along piles to measure load-resistance characteristics under applied lateral loads. The back-calculated P-y curves from strain gages were compared with estimated P-y curves using theoretical methods based on geotechnical investment data. Back-calculated P-y curves from field tests for sand and clay ground conditions were presented in this paper, which are different from theoretical P-y curves. By using the research results of this study, more accurate estimations of pile design under lateral loads can be available for similar geotechnical conditions.

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An improved algorithm in railway truss bridge optimization under stress, displacement and buckling constraints imposed on moving load

  • Mohammadzadeh, Saeed;Nouri, Mehrdad
    • Structural Engineering and Mechanics
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    • v.46 no.4
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    • pp.571-594
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    • 2013
  • Railway truss bridges are amongst the essential structures in railway transportation. Minimization of the construction and maintenance costs of these trusses can effectively reduce investments in railway industries. In case of railway bridges, due to high ratio of the live load to the dead load, the moving load has considerable influence on the bridge dynamics. In this paper, optimization of the railway truss bridges under moving load is taken into consideration. The appropriate algorithm namely Hyper-sphere algorithm is used for this multifaceted problem. Through optimization the efficiency of the method successfully raised about 5 percent, compared with similar algorithms. The proposed optimization carried out on several typical railway trusses. The influences of buckling, deformation constraints, and the optimum height of each type of truss, assessed using a simple approximation method.