• Proceedings of the KSR Conference
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• 2005.11a
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• pp.836-841
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• 2005

As gravel roadbed is gradually turn down by repetitive loading of train, lasting work for maintenance and management of track is necessary to reduce the settlement of roadbed and the deterioration of track. Despite of above weak point, gravel roadbed has become a basic structure of roadbed at the present time. But request for new structure of roadbed is recently presented to settle an increased transportation capacity of track, and to solve a shortage of the labor to handle maintenance work of track. Therefore, we begin to research about maintenance-free roadbed like paved track from two years ago. In this study, a series of tests were performed to clarify the characteristics of strength and permeability of concrete specimen, which is the upper part of paved track injected by cement mortar, by type of geotextile and finally to give a basic data for application of geotextile to the lower part of paved track.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.511-516
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• 2007

Rubber wheeled AGT(Automated Guide-way Transit) system is a prominence transportation system for urban area, because of its low construction cost and management, low noise and vibration and fine exterior view. AGT system uses concrete tracks. Concrete can be easily damaged by the impact, change of temperature and external loads. The fault of concrete track is harmful not only to riding quality but also to bridge. Therefore, in this study, the effects of railway prominence to the bridge are surveyed by experimental method. The experiment was executed for PSC bridge at AGT test line in Kyungsan. And the test results for 5mm, 10mm prominence and without prominence are compared and investigated, according to the vehicle speed.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.262-270
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• 2011

Track support stiffness which affected track maintenance and riding comfort had a big effect on the track and train. Also, track support stiffness of the track design which was based on theory differs from track support stiffness of the track generated on the field. Track support stiffness was generated by several factors such as dynamic wheel loads, vertical displacement of track, and stress at rail bottom on the field test. With the results of the field test was compared with theoretical value. This paper analyzed that track support stiffness of ballast depended on condition of ballast, and support stiffness of concrete track also depended on the characteristic of track structures such as, normal elastic fastening system, rail floating system and sleeper floating system. However, on the ballast and concrete track, the designed track support stiffness was underestimated less than the measured track support stiffness. When the track condition was estimated on service line, it would not consider the track condition on the field. Therefore, this study proposed the various track type and the range of track support stiffness based on the experimental test.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.256-260
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• 2010

It has been proved that precast slab track has advantage of rapid construction speed and good quality compared to in-situ concrete slab track. A korean precast slab track, which is named as a K-PST, was developed and had been installed on the embankment and explored on the air. The developed track system consists of precast track panel and underpouring layer which is made of cement-asphalt mortar. Consequently, poor filling of underpouring layer directly could affect on the long-term performance of the track system. As a preliminary study, the effect of the poor infilling of the underpouring in precasst slab track system on structural behavior was investigated through FEM analysis.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1637-1646
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• 2008

Deformations of bridge deck ends on abutment can cause extreme deformations on track. Especially, since slab track was fixed onto the bridge deck slab on concrete slab track installed bridges, deformations of bridge deck ends directly affect the slab track behavior, and thus these interactions can bring about the premature failure of rail fastenings or other deteriorations to lower the serviceability. In this study, a foreign standard to evaluate forces on track components caused by the track-bridge interactions and the behavior of bridge deck ends was investigated and for real scale bridges. It was found that rail support spring coefficients, as well as toe loads, support spacing were very important parameters.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.862-867
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• 2004

In this paper, the crack properties of steel fiber reinforced concrete (SFHC) beams by experimental method are discussed. The major role played by the steel fiber occurs in the post-cracking zone, in which the fibers bridge across the cracked matrix. Because of its improved ability to break crack, SFRC has better crack properties than that of reinforced concrete (RC). Crack properties are influenced by longitudinal reinforcement ratio, volume and type of steel fiber, strength of concrete and the stress level. Crack width and crack number in the SFRC beams havebeen evaluated from experimental test data at various levels in the beams.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6788-6798
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• 2015

In recent high speed rail way, the operating speed of train is enhanced and the introduction of EMU train vehicles is increased. In addition, as expected the demand of the concrete slab track and the trend of design cross-section reduction, the clear behavior of evaluation of internal slab layer is demanded about the variation of design load and speed. The purpose of this study is to evaluate and identify the mechanical behavior pattern of concrete slab track and track-road bed with the variation of axle load and train speed. To this end, the behavior of TCL and HSB was evaluated in according to the variation of axle load and speed. And the analysis results and the data measured TCL strain sensor, which was embedded in TCL slab under installation on Honam high speed railway, was analyzed. The analysis result shows that the strain are increasing in according to the speed-up of train, and line regression was obtained from measured data. Analysis data of the state of bonding condition of slab layer and measured data was analyzed. It is conducted that the TCL layer stress of HEMU 430X, which of axle load, is lighter was similar to the stress of KTX-Honam, the standard deviation of measured stress is dramatically increased.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2163-2173
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• 2011

In this study, the deformations and stresses occurred in the elastic rail fastening system were evaluated according to applied extreme track forces based on various field conditions, track curvature and poor properties. The purpose of this study is to establish a method for efficient management and suggest guide line for track construction in order to secure the performance quality of the elastic rail fastening system on the sharp curved track.. Therefore, initial construction qualities of rail and concrete bed, initial clamping force and applied extreme track forces were used into experiment as several parameters. Using these test results, the performance characteristics of the elastic rail fastening system were also evaluated. As a result, it suggested the method to secure long-term durability of fastening system and comparing sharp curved track to results on field test.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.756-762
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• 2004

Up to now, the only way is Floating Slab Track System, which cuts off vibration by installing spring between concrete slab and ground for the lines of particularly requiring attenuating vibration. The weak point of Floating Slab Track System is large increase of construction cost because normally the structure is getting bigger. In regards to this matter, Floating Rail Track System has been developed, which cuts off vibration by floating the first cause of vibration rail, and the system is in operation. In the thesis, the application of new attenuating vibration track system has been confirmed by studying theoretical background of Floating Rail Track System and evaluating dynamic deflection of track and attenuating of noise and vibration performance through various measurements from laboratory tests and site inspection.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.382-388
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• 2005

SMSC(Seoul Metropolitan Subway Corporation) is substantially taking the core role of mass transit system in Seoul Metropolitan area. When it was built, the design had challenged to sharp curved tracks less than 250m radius considering the protection of buildings and cultural properties as well as the connection to ground roads. Such circumstances have required a certain extent of slack in track geometry and therefore led to the construction of ballasted track with wooden sleepers. However, the dynamic force from running on sharp curved track has caused the misalignment and abnormal failure of track geometry, and it has resulted in a frequent maintenance and repair works which require a lot of cost and manpower. In this paper, we present the construction case of maintenance-free track system by using of concrete sleeper and elastic rail fastening system to ensure the safety of both passengers and trains, and to contribute the effective maintenance for track facilities of SMSC.