• 제목, 요약, 키워드: Rail Stability

검색결과 218건 처리시간 0.037초

지반-구조물 상호작용을 고려한 교량상 장대레일의 비선형 지진응답해석 (Nonlinear earthquake response analysis of CWR on bridge considering soil-structure interaction.)

  • 신한철;조선규;양신추;최준성
    • 한국철도학회:학술대회논문집
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    • pp.733-738
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    • 2004
  • Recently continuous welded rail is generally used to ensure running performances and to overcome the problems such as structural vulnerability and fastener damage at the rail expansion joint. Though the use of continuous welded rail on bridge has the advantage of decreasing the vibration and damage of rail, it still the risk of buckling and breaking of rail due to change of temperature, starting and/or breaking force, axial stress concentration and so on. So, VIC code and many methods has been developed by researchers considering rail-bridge interaction. Although there are many research concerning stability of continuous welded rail about temperature change on bridge and starting and/or breaking force, the study of continuous welded mil for earthquake load is still unsufficient. In this study, the nonlinear seismic response analysis of continuous welded rail on bridge considering soil-structure interaction, geotechnical characteristic of foundation and earthquake isolation equipment has been performed to examine the stability of continuous welded rail.

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고속철도 교량상 장대레일의 하절기 온도응력 계측 (Field Test to Investigate the Thermal Stress of Continuous Welded Rail on High Speed Railway Bridges in Summer Period)

  • 곽종원;최은석;진원종;이정우;김병석;강재윤
    • 한국철도학회논문집
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    • v.9 no.2
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    • pp.131-136
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    • 2006
  • Most modern railways, especially the high speed railway tracks, use continuous welded rail(CWR) for the less maintenance. For the CWR track has very few expansion joints, track buckling has always been an unpredictable event and it happens mainly by high compressive stress in rail in summer period. Therefore, it is important to understand the variation of rail stress induced by thermal loads which has direct influence on the rail buckling and stability of railway track. This paper describes the experimental investigation of the variation of rail temperature and stress in a high speed railway track on bridge structure. Field measurement was performed to examine the correlation between the rail temperature and rail stress on the Korean High Speed Railway line. Regression functions were derived from measured data to determine the rail stress f3r an arbitrary rail temperature varies from 20 to 50 degree Celsius.

Parametric Study of Thermal Stability on Continuous Welded Rail

  • Choi, Dong-Ho;Na, Ho-Sung
    • International Journal of Railway
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    • v.3 no.4
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    • pp.126-133
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    • 2010
  • The thermal buckling analysis of curved continuous welded rail (CWR) is studied for the lateral buckling prevention. This study includes a thermal buckling theory which accounts for both thermal and vehicle loading effects in the evaluation of track stability. The parameters include rail size, track lateral resistance, track longitudinal and torsional stiffnesses, initial misalignment amplitude and wavelength, track curvature, tie-ballast friction coefficient and truck center spacing. Parametric studies are performed to evaluate the effects of the individual parameters on the upper and lower critical buckling temperatures. The results show that the upper critical buckling temperature is highly affected by the uplift due to vehicle loads. This study provides a guideline for the improvement of stability for dynamic buckling in curved CWR track.

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장대레일 궤도의 안정성에 미치는 체결장치의 실험적 연구 (An Experimental Study of Fastening System on CWR(Continuous Welded Rail) Track Stability)

  • 김정훈;한상윤;임남형;강영종
    • 한국철도학회:학술대회논문집
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    • pp.317-324
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    • 2007
  • Until now, the railway has been constructed using track with jointed rails of relatively short lengths to allow thermal expansion in hot summer months. These joints weaken the track structurally and increase track maintenance cost and power consumption of the running train. The CWR(Continuous Welded Rail) Track is the solution of these drawbacks. Although the CWR track not only reduces the track maintenance cost but also increases the life cycle of track components, the stability of the track is highly affected by change of temperatures and vehicle load. A three dimensional nonlinear analysis which considers rail, fastening system and tie has been performed to understand structural behavior of the CWR track. In this case, the translational and rotational stiffness values of fastening system have not been studied. The fastening system makes ties and rails connect. In this study, the stiffness values of various types of fastening systems which consist of clips, rail-pads and insulators are determined by the experiment. The experimental results of the fastening system are compared with the results of parametric study that is performed to investigate the sensitivity of fastening system on stability of CWR track.

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

  • 민경주;김영국;우용근
    • 한국철도학회:학술대회논문집
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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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Effect of temperature gradient on track-bridge interaction

  • Kumar, Rakesh;Upadhyay, Akhil
    • Interaction and multiscale mechanics
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    • v.5 no.1
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    • pp.1-12
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    • 2012
  • Considerable longitudinal rail forces and displacements may develop in continuous welded rail (CWR) track on long-span bridges due to temperature variations. The track stability may be disturbed due to excessive relative displacements between the sleepers and ballast bed and the accompanied reduction in frictional resistance. For high-speed tracks, however, solving these problems by installing rail expansion devices in the track is not an attractive solution as these devices may cause a local disturbance of the vertical track stiffness and track geometry which will require intensive maintenance. With reference to temperature, two actions are considered by the bridge loading standards, the uniform variation in the rail and deck temperature and the temperature gradient in deck. Generally, the effect of temperature gradient has been disregarded in the interaction analysis. This paper mainly deals with the effect of temperature gradient on the track-bridge interaction with respect to the support reaction, rail stresses and stability. The study presented in this paper was not mentioned in the related codes so far.

비선형 크립이론을 이용한 한국형 고속전철의 동특성 해석 (Analysis of Dynamic Behaviors for the Korea High Speed Train(KHST) by Using Non-Linear Creep Theory)

  • 박찬경;김석원;김회선
    • 한국소음진동공학회:학술대회논문집
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    • pp.1093-1098
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    • 2002
  • Dynamic behaviors of the Korean High-speed Train(KHST) have been analyzed to investigate the performance on the stability, the safety and the ride comfort. Multi-body dynamics analysis program using Recursive method, called RecurDyn, have been employed in the numerical simulation. To model the wheel-rail contact, the RecurDyn uses its built-in module which uses the square root creep law. The accuracy of the rail module in RecurDyn. however, decreases in the analysis of flange contact because it linearizes the shape of the wheel and rail. To solve this problem, a nonlinear contact theory have been developed that considers the profiles of the wheel and rail. The results show that the KHST still needs more stability. The problem should be solved by the examinations of module and modeling.

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강우시 사면안전율 변화를 이용한 열차운전규제기준 개발 (The Development of Rail-Transport Operation Control using the Variation of Slope Stability under Rainfall)

  • 김현기;이진욱;신민호
    • 한국철도학회:학술대회논문집
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    • pp.397-402
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    • 2003
  • Infiltration of rainfall causes railway embankment to be unstable and may result in failure. Basic relationship between the rainfall and stability of railway embankment are defined to analyze the stability of embankment by rainfall. An experimental study for defining of infiltration rate of rainfall into slope is conducted in the lab. The results of Rainfall infiltration show that rainfall infiltration is not equal to infiltration as like reservoir because rate of rainfall infiltration is controlled by slope angle. Based on these results, boundary condition of rainfall is altered and various numerical analysis are performed. The variation of shear strength, the degree of saturation and pore-water pressure for railway slope during rainfall can be predicted and the safety factor of railway slope can be expressed as the function of rainfall amount, namely rainfall index. Therefore, it is judged that this rainfall index can be a good tool for the rail-transport operation control.

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소형무인경전철(PRT)궤도 레일이음매의 동적거동 분석 (Evaluation of Dynamic Behavior of Rail Joints on Personal Rapid Transit Track)

  • 최정열;김준형
    • 한국안전학회지
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    • v.31 no.5
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    • pp.89-94
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    • 2016
  • The objective of this study was to estimate the dynamic behavior of a personal rapid transit(PRT) track system using a rail of rectangular tube section and a rail joint of sliding type, and to compare the results with the normal rail and rail joint of a PRT track system by performing field measurements using actual vehicles running along the service lines. The measured vertical displacement of rail and sleeper, and vertical acceleration of rail for the normal rail and rail joint section were found to be similar, and the rail joint of sliding type satisfied the design specifications of the track impact factor for a conventional railway track. The experimental results showed that the overall dynamic response of the rail joint were found to be similar to or less than that of the normal rail, therefore the rail joint of sliding type for PRT track system was sufficient to ensure a stability and safety of PRT track system.

일반체결구/활동체결구 접속구간 차량 및 궤도 안정성 평가에 관한 연구 (A Study on Stability Assessment of Vehicle and Track on Transition between Conventional and Zero-Longitudinal Resistance Rail Fastener)

  • 양신추;장승엽;김은;유진영;홍성모
    • 한국철도학회:학술대회논문집
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    • pp.1078-1083
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    • 2008
  • In this paper, assessed are the stability of vehicle and track according to vertical support stiffness difference on the transition between conventional and zero-longitudinal resistance (ZLR) rail fastener on bridge. For this, the spring constants of rail fastener have been determined according to different load ranges - KTX load (with or without impact factor) and test load of EN standards - from results of laboratory test on rail pad, the stability analysis of vehicle and track has been performed according to numbers or installation length of ZLR fasteners using vertical vehicle-track coupled model to consider train-track interaction. The analysis results reveal that only the wheel load variation slightly exceed the limit value when 2 ZLR fasteners are used with spring constant determined within the EN test load range, but, in all other cases, all evaluation items are satisfied. Thus, it can be said that the stability of vehicle and track will not be degraded by ZLR fastener.

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