• Journal of the Korean Society for Railway
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• v.5 no.1
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• pp.1-9
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• 2002

Where the track is continuously welded over the bridge, the longitudinal forces will be distributed interactively between the track and the sub-structure by the rail-bridge interaction mechanism. The ratio between the longitudinal forces transmitted in each elements depends on the magnitude of the ballast resistance and the stiffness of the sub-structures. In this paper, the main factors affect on the longitudinal rail force are discussed and the parametric study for the behavior of CWR(Continuous Welded Rail) track was executed. It is concluded that the horizontal ballast resistance and the stiffness of the bridge sub-structure are the significant parameters affecting the stability of the continuous welded rail track.

• Proceedings of the KSR Conference
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• 2007.05a
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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.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1460-1465
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• 2007

CWR(Continuous Welded Rail) and bridge interaction produce rail force, bridge displacement and rail/bridge relative displacement. Each of these has limitation by many codes. In this paper, analysis of interaction has been carried out by using foreign codes(UIC 774-3 R code of Europe etc.) because there is no code about interaction between rail and bridge in Korea. Recently, railway bridges with CWR has been constructed for structural and economical reasons. When designer plans railway bridges, design a bridge model first and then investigate railway forces and displacement by interaction analysis. If these results go out bounds from limitation, designer plans railway bridges again and again. In this paper, using the parametric study on CWR and railway bridge interaction, railway bridge parameters such as length of bridge span, area of bridge, moment of inertia, stiffness of pier, etc. are presented. It helps preliminary design of railway bridges.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1469-1470
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• 2010

• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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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.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.303-306
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• 2007

CWR(Continuous Welded Rail) and bridge interaction produce rail force, bridge displacement and rail/bridge relative displacement. Each of these has limitation by many codes. In this paper, analysis of interaction has been carried out by using foreign codes(UIC 774-3 R code of Europe etc.) because there is no code about interaction between rail and bridge in Korea. Recently, railway bridges with CWR has been constructed for structural and economical reasons. When designer plans railway bridges, design a bridge model first and then investigate railway forces and displacement by interaction analysis. If these results go out bounds from limitation, designer plans railway bridges again and again. In this paper, using the parametric study on CWR and railway bridge interaction, railway bridge parameters such as length of bridge span, area of bridge, moment of inertia, stiffness of pier, etc. are presented. It helps preliminary design of railway bridges.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.369-375
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• 2009

The Periodic replacements criterion of rail is calculated on the basis of the research result of RTRI in Japan. It is suggested that the service life of the continuous welded rail(CWR) is estimated by the relationship between the rail surface irregularity according to the accumulated passing tonnage and bending fatigue of welded part in CWR. In order to establish the periodic replacements criterion of CWR, this study measured the rail surface irregularity according to the accumulated passing tonnage, the types of track system and welding. Therefore, it is analyzed that the gas pressure welding is the worst one of the others. In addition, it is analyzed that the rail surface irregularity growth rate in ballast track is about $0.02{\sim}0.03mm$/100MGT and its in concrete track is about $0.005{\sim}0.02mm$/100MGT Finally, the result of this study is able to use the basis data to establishing the periodic replacements criterion of CWR considering rail grinding.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.159-168
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• 2007

The problem of determination of axial force in continuous welded rail(CWR) has attracted a number of railroad engineers due to its practical importance in prevention of accidents related to buckling and pull apart. In this paper, we investigated the application of the beam-column theory to presume the axial force in CWR and proposed the development process of the prediction equation and model to presume the axial force in CWR.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.64-71
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• 2010

It is suggested that the service life of the continuous welded rail(CWR) is estimated by the relationship between the rail surface irregularity according to the accumulated passing tonnage and bending fatigue of welded part in CWR. In this study, based on the results of bending fatigue tests of rail and results of measuring tests in situ of rail bending stress, this study estimated the bending fatigue life of welded rail in concrete track, adopting a Haibach's rule. The bending fatigue life of CWR considered the rail surface irregularity, train speed and the S-N curve by types of rail welding. In addition, this study estimated it for the fracture probability 1%, 0.1%, 0.01%. Therefore, this study proposed bending fatigue life of CWR in concrete track.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.458-461
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• 2007

Recently, the continuous welded rail(CWR) track has been used for less maintenance of the High-speed railway tracks. In case of CWR track, track buckling has always been an unpredictable event under the high compressive stress in rail. The behavior and stress state of CWR track is manily influenced by its thermal variations, and it is important to understand seasonal variations of rail temperature and stress to predict the track stability. This paper describes the in-site measurement for the rail temperature and rail stress, and the correlation between the rail temperature and stress was examined.