• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.1
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• pp.55-61
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• 2017

Recently several researches have been conducted to develop sliding track system in which friction between concrete track and bridge slab has been reduced. This paper investigated shear load carrying capacity of lateral supporting concrete block which should be implemented to resist lateral load due to train in sliding track system. In order to evaluate shear load carrying capacity of lateral supporting concrete block, analytical model has been developed considering concrete friction and rebar dowel action along construction joint. The proposed model predicted test results on the shear load carrying capacity from literature conservatively by 13~23% because effect of aggregate interlock along crack surface was neglected. Since construction joint status is ambiguous on construction site, it can be concluded that the proposed model can be used for reasonable design of lateral supporting concrete block. Based on the proposed model, design proposal for lateral supporting concrete block has been established.

• Proceedings of the KSR Conference
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• 2006.05b
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• pp.408-414
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.29-30
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• 2006

The interior noise of KTX in tunnel has become an issue since the commercial operating in April 2004. The analysis of the interior noise of KTX in tunnel with concrete track shows sharply increased noise level in the range of 80Hz that is the natural frequency of the KTX carbody. We know that the booming noise inside KTX in tunnel with concrete track is generated by noise outside gangway and rolling noise at the carbody natural frequency. In this Study noise reduction methods are discussed on the basis of the comparison of the KTX and KHST noise characteristics. Alternatively, the effect of the modified mud-flap on the interior noise is introduced.

• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.270-280
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• 2014

In this study, to examine the causes of cracks in continuously reinforced concrete tracks (CRCTs) and the main factors affecting cracking, a field survey on the status of cracks and crack patterns in the Gyeong-bu high speed line was conducted, and the crack patterns of CRCT due to the temperature difference between the top of the slab (TCL) and the bottom of the subbase (HSB) and the drying shrinkage of concrete were predicted by a nonlinear finite element model considering the structure of CRCT. The results of the numerical analysis show that cracks will be developed at the interface between the sleeper and the TCL, and under the sleeper due to the temperature difference and concrete shrinkage. This corresponds well to the crack locations found in the field. Also, it is found that the most significant factors are the coefficient of thermal expansion with respect to the temperature difference, and the drying shrinkage strain with respect to shrinkage. According to the results, the reinforcement ratio should be carefully determined considering the structures of CRCT because the crack spacing is not always proportional to the reinforcement ratio due to the sleepers embedded in the TCL.

• Magazine of the Korea Concrete Institute
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• v.16 no.4 s.81
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• pp.10-17
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• 2004

• Magazine of the Korea Concrete Institute
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• v.26 no.1
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• pp.41-45
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• 2014

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.517-528
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• 2007

Domestic or international existing researches regarding rail damage factors are focused on laying, vehicle conditions, driving speed and driving habits and overlook characteristics of track structure (elasticity, maintenance etc). Also in ballast track, as there is no special lateral spring stiffness of track also called as ballast lateral resistance in concrete track, generally, existing study shows concrete track has 2 time shorter life cycle for rail replacement than ballast track due to abrasion. As a result of domestic concrete track design and operation performance review, concrete track elasticity is lower than track elasticity of ballast track resulting higher damage on rail and tracks. Generally, concrete track has advantage in track elasticity adjustment than ballast track and in case of Europe, in concrete track design, it is recommended to have same or higher performance range of vertical elastic stiffness of ballast track but domestically or internationally review on lateral spring stiffness of track is very minimal. Therefore, through analysis of service line track on site measurement and analysis on performance of maintenance, in this research, dynamic characteristic behaviors of commonly used ballast and concrete track are studied to infer elasticity of service line track and experimentally prove effects of track lateral spring stiffness that influence curved rail damage as well as correlation between track elasticity by track system and rail damage to propose importance of appropriate elastic stiffness level for concrete and ballast track.

• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.298-303
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• 2010

The transition zone of the railway is the section which roadbed stiffness is suddenly varied like as tunnel-earthwork, bridge-earthwork and concrete track-ballasted track. There are about 450 tunnel-bridge transition sections on Kyungbu high-speed railway line. It is very important to pay careful attention to construction of these transition zones, in order to secure the train running safety. So, we developed a finite element model of the moving wheel loading to simulate the behavior of bridge-earthwork transitions in this paper. The most distinctive characteristics of the model proposed is to simulate the real wheel behavior on rail. And the main analysis object is to evaluate and compare the deformation characteristics of the transition zone according to the reinforcement methods and length of transition zone which is adopted to high-speed railway. Based on the analysis results, we assessed the effect of the reinforcements on the transition zone of high-speed railway.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.638-646
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• 2016

CWR (continuous welded rail) tracks on high-speed railway bridges have much more complicated axial force distributions caused by track-bridge interaction than those behaviors on embankments, and additional problems caused by track-structure interaction with the axial force of the CWR. In order to analyze and limit other physical phenomena caused by track-bridge interaction, a design guideline (KR C-08080, longitudinal track-bridge interaction analysis) is used when designing CWR track on bridges. Domestic analysis and design methods for track-bridge interaction follow the UIC 774-3R, and they suggest conservative methods and deterministic properties. Recently, many studies analyzing the methods of track-bridge interaction considering the loading history are being carried out; however, there has been insufficient studies of the variation of the resistance properties with a consideration of the actual loading history. In this study, the performances of rail fastening systems used for concrete track on bridges were tested and analyzed while considering the loading history. For this purpose, longitudinal and vertical loading combinations, applied in order to simulate the practical conditions and resistance characteristics (stiffness and elastic limit displacement), are analyzed through the experimental results. Also, a comparison study was conducted with the properties in the KR Code.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.905-913
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• 2008

Recently, concrete tracks are introduced into high-speed railroads as an alternative to ballast tracks. Concrete tracks are superior to ballast tracks in the aspect of durability, maintenance and safety. However, deteriorated stiffness of railroad bed and settlement of soft ground induced by trapped or seepage water lead to problems in safety of train operation. In this research, flexural rigidity of concrete tracks was employed as an index of track displacement and a new seismic technique called FRACTAL (Flexural-Rigidity Assessment of Concrete Tracks by Antisymmetric Lamb Waves) method was proposed to delineate flexural rigidity of concrete tracks in a 2-D image. In this paper, to establish theoretical background, parametric research was performed using numerical simulations of stress-wave tests at concrete tracks. Feasibility of the FRACTAL technique was proved at a real concrete track for Korean high-speed trains. Validity of the FRACTAL technique was also verified by comparing the results of impulse-response tests performed at the same measurement array and the results of DC resistivity survey performed at a shoulder nearby the track.