• Proceedings of the KSR Conference
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• 2008.11b
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• pp.117-124
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• 2008

Construction of concrete slab track is trending to increase gradually in national and international for reduction in track maintenance cost and secure of ride comfort. However, in case of railway bridge installed concrete slab track, the serviceability review of end deck should be performed for reducing the maintenance cost of track. The serviceability review of track contains that the compression force which is occurred on fastener of end bridge should be smaller than the compression force causing the deformation limit of elastic pad and the uplift force which is occurred on fastener of end abutment should be smaller than initial fastening force. Therefore, this study calculated the deflection and end rotation of the railway bridge according to the span length and stiffness of railway bridge and estimated the compression force and uplift force which are occurred on the track of end bridge using the finite element method. This study indicated the several diagrams that are contained the correlation between the behaviour of the track and the behaviour of the railway bridge. As a result, to reduce the end rotation of the railway bridge is very efficient to increase the height of railway deck.

• 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.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.207-216
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• 2013

The components of concrete track (rail and rail fastening system) in railway bridge deck ends are damaged and deteriorated by track-bridge interaction forces such as uplift forces and compression forces owing to their structural flexural characteristics (bridge end rotation). This had led to demand for alternatives to improve structural safety and serviceability. In this study, the authors aim to develop a transition track to enhance the long term workability and durability of concrete track components in railway bridge deck ends and thereby improve the performance of concrete track. A time-history analysis and a three-dimensional finite element method analysis were performed to consider the train speed and the effect of multiple train loads and the results were compared with the performance requirements and German standard for transition track. Furthermore, two specimens, a normal concrete track and a transition track, were fabricated to evaluate the effects of application of the developed transition track, and static tests were conducted. From the results, the track-bridge interaction force acting on the track components (rail displacement, rail stress, and clip stress) of the railway bridge deck end were significantly reduced with use of the developed transition track compared with the non-transition track specimen.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.436-442
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• 2011

It is increasing construction of long span railway bridge with concrete track system for speed up of railway and efficient maintenance of track. As the sleeper of the concrete track system layed on a bridge is fixed on deck of the bridge, the displacement of the sleeper and deck is same. Therefore, the spacing between two sleeper installed at the end of the adjacent deck near the expansion joint of bridge becomes vary according to the longitudinal expansion of a deck by temperature change. By the way, if the spacing of sleepers become increase excessively, it causes large bending stress of in a rail, and it can leads failure or reduction of fatigue life of the rail. And also the excessive displacement of the rail may induce decrease ride comfort. Therefore, in order to prevent such problems, the allowable maximum sleeper spacing at a bridge expansion joint was mutually determined. And, the determination procedure of the maximum bridge expansion length based on the allowable sleeper spacing was suggested.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1248-1253
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• 2011

It is increasing construction of long span railway bridge with concrete track system for speed up of railway and efficient maintenance of track. As the sleeper of the concrete track system layed on a bridge is fixed on deck of the bridge, the displacement of the sleeper and deck is same. Therefore, the spacing between two sleeper installed at the end of the adjacent deck near the expansion joint of bridge becomes vary according to the longitudinal expansion of a deck by temperature change. By the way, if the spacing of sleepers become increase excessively, it causes large bending stress of in a rail, and it can leads failure or reduction of fatigue life of the rail. Further more, the excessive displacement of the rail may induce decrease ride comfort as well as corrugation of rail surface. Therefore, it is required to determine the allowable maximum sleeper spacing to prevent such problems. For the purpose, investigation on the influence factor on sleeper spacing for straight track was carried out. Variation of bending moment in a rail, wheel force, and the ratio of primary and secondary deflection of the rail according to sleeper spacing was investigated, and, as a result, the maximum allowable sleeper spacing at the bridge expansion joint was suggested.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.71-79
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• 2008

The concrete track is being used at the Phase II of the Kyeongbu High Speed Railway and New Constructed Honam High Speed Railway. When it makes a decision of bridge type, It has to consider about longitudinal forces of Continuous Welded Rail, Displacement at the end of bridges, Up-lift forces for fastener on the track. If it is installed turnout on the bridge, There is likelihood of the deck twist by applying the each difference longitudinal forces at the 4 each rails and the buckling by concentration of rail stress at the turnout. Moreover, If it is installed turnout on the continuous bridge and REJ(Rail Expansion Joint) on the main track or turnout track. It is hard to keep a safety for rail because of coming to twist or folding at the expansion of deck on the turnout track. Therefore when it is a design of bridge with turnout. It need to take bridge type to minimize an additional axial force and a displacement at the turnout. This paper makes a study of the composite steel arch bridge that is able to resolve criteria requirements of safety for track with turnout and suggest a helpful design method for bridge considering track with turnout by being based on design and construction method of Eonyang Bridge at the north part of Ulsan Station in Phase II of the Kyeongbu High Speed Railway.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1188-1195
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• 2007

The vertical forces in rail fasteners at areas of bridge transitions near the embankment and on the pier will occur due to different deformations of adjoining bridges caused by the trainloads, the settlement of supports, and the temperature gradients. The up-lifting forces is not large problem in the blast track because the elasticity of blast and rail pad buffs up-lifting effect. But, it is likely to be difficult to ensure the serviceability of the railway and the safety of the fastener in the end in that concrete slab track consist of rail, fastener, and track in a single body, delivering directly the up-lifting force to the fastener if the deck is bended because of various load cases, such as the end rotation of the overhang due to the vertical load, the bending of pier due to acceleration/braking force and temperature deviation, the settlement of embankment and pier, the temperature deviation of up-down deck and front-back pier, and the rail deformation due to wheel loads. The analysis of the rail fastener is made to verify the superposed tension forces in the rail fastener due to various load cases, temperature gradients and settlement of supports. The potential critical fasteners with the highest uplift forces are the fastener adjacent to the civil joint. The main influence factors are the geometry of the bridge such as, the beneath length of overhang, relative position of bridge bearing and fastener, deflection of bridge and the vertical spring stiffness of the fastener.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.260-269
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• 2014

Transition tracks are an alternative for enhancing the long-term serviceability and durability of concrete track components in railway bridges. The goal of this paper is to investigate the structural behavior for transition track systems of railway bridge deck ends. In this study, the structural behavior of transition tracks such as the variations in static, dynamic, and fatigue behaviors and dynamic properties (natural frequency and damping ratio) are assessed and compared through performing loading tests and finite element analyses using actual vehicle impact loadings. As a result, it is found that the structural behavior of the transition track system is expected to satisfy the actual vehicle impact loading, and the variation in the neutral axis and dynamic characteristics are not affected by the fatigue loading. Therefore, it is inferred that the structural capacity and long-term durability of the transition track system is proven.

• 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.

• Steel and Composite Structures
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• v.35 no.1
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• pp.29-41
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• 2020

Cross-beams of modern through truss bridges are connected to truss chord at its nodes and between them. It results in variable rotational end restraint for cross-beams, thus variable bending moment distribution. This feature is captured in three-dimensional modelling of through truss bridge structure. However, for preliminary design or rapid assessment of service load effects such technique of analysis may not be available. So an analytical method of assessment of rotational end restraint for cross-beam of through truss bridges was worked out. Two cases - nodal cross-beam and inter-nodal cross-beam - were analyzed. Flexural and torsional stiffness of truss members, flexural stiffness of deck members and axial stiffness of wind bracing members in the vicinity of the analyzed cross-beam were taken into account. The provision for reduced stiffness of the X-type wind bracing was made. Finally, general formula for assessment of rotational end restraint was given. Rotational end restraints for cross-beams of three railway through truss bridges were assessed basing on the analytical method and the finite element method (three-dimensional beam-element modelling). Results of both methods show good agreement. The analytical method is able to reflect effects of some structural irregularities. On the basis of the obtained results the general values of rotational end restraint for nodal and inter-nodal cross-beams of railway through truss bridges were suggested.