• 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.

• 전기의세계
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• v.13 no.1
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• pp.16-19
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• 1964

한강대교의 전식상황을 예비조사한 결과 철교상에 가설된 전차궤도의 누설전류로 인하여 한강대교가 전식당하고 있음을 발견하였다. 그리하여 금반 건설부와 서울특별시 건설국의 예산으로 본 전력연구소 전식연구실에서 전식작용의 실태를 본격적으로 조사하여 교량의 유지관리를 합리화 시키고자 본 조사를 착수하여든 것이다. 전식에 대한 개요는 본 학회지 제 12집에서 양론하였으므로 본 논문에서는 생략하기로 한다.

• 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.

• Journal of the Korean Professional Engineers Association
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• v.30 no.4
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• pp.88-98
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• 1997

For Improving gradually inferior environment of public transportation system, it is necessary to introduce new transit System(NTS). NTS is defined as automated economicm system for it's operation . The Track Guided Bus System (TGBS) is one of the NTS, which is possible operating on the track or road surface and the system has actually many advantages. This study was concentrated on investigating the characteristics of TGBS, comparing to the other public transportation system and appraising the advantages of it on the benefit of the passenger side as well as investor, and then suggested applicable routes. As the result of the study, it is concluded that the advantage of this system is less transfering and initial low investment. Applicable route is the demand of passengers in the range of PPHPD 5,000~39,600, which is more than bus but not more than subway.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.537-542
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• 2023

Recently, deformation of operating railway structures has occurred due to adjacent excavation works such as new structures and utility tunnel expansion concentrated around downtown areas. However, most of them are focused on structural review, repair and reinforcement of structures. A review of the Track is insufficient. In particular, in the case of the gravel track on the earthwork subgrade, the subgrade and the ballast are not solidified. A slight level of deformation can cause ballast relaxation. Sleeper support conditions may lead to unstable conditions. Sufficient safety must be ensured. In addition, it is a track type with a high risk of train derailment due to unstable support conditions. In this study, the correlation between the deformation characteristics of gravel tracks and track support performance according to subgrade deformation is experimentally and analytically verified. In addition, an evaluation technique that can evaluate the condition of the gravel track and the track support stiffness is presented.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.123-133
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• 2004

The evaluation standard method of weld zone in rails is not exhibited in case of the domestic and the outside about ultrasonic inspection method. therefore, practical affairs a mans on the ground know very little about evaluation method of pass and failure. This paper discuss about ultrasonic exploration of weld zone in railway rails to know practical affairs a mans that the first, "problem and improvement direction of domestic track construction specifications applied according to a place ordering" and the second, "the method applied of ultrasonic exploration test of weld zone in railway rails".

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.143-154
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• 2012

The wireless low-floored tram is an innovative transportation system which is environment-friendly and highly energy-efficient. In addition, the system has various advantages such as low construction cost, improvement of urban landscape, revitalization of surrounding commercial area, elevated convenience for passengers, etc. Therefore, more than ten local governments have proposed tram construction projects in Korea. Accordingly, many research and development projects are ongoing funded by government including the developments of tram vehicle, tram trackway, signal system, etc. The embedded rail system are commonly used in order to provide leveled roadway surface in urban area. It is effective to reduce the noise and vibration, caused at the interface between the wheel and track, to minimize the construction period, and to lower the maintenance cost. This paper investigated the design and construction processes for tram trackway and figured out the constructability for the test track with embedded rail system for the first time in Korea. The performance to reduce the noise and vibration were quantitatively measured in the test track with embedded rail system. In addition, the results were compared to the ones for track with conventional rail system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.101-107
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• 2017

Over-break, which is excavated larger than planned line at tunnel excavation, is inevitable due to the nature of blasting. But regarding the bottom of the foundation, most of the domestic ordering organizations pay only 10 cm thick filled concrete when pouring concrete due to over-break. In accordance, the construction cost will increase greatly if all the depths of the designed over-break are filled only with concrete. When tunnel excavation occurs, concrete filling of 18 MPa(T = 100 mm) and 150 mm~237 mm auxiliary concrete layer and 240 mm concrete track(TCL) are applied to the upper part. The concrete is installed in an excessive amount of about 600 mm between the lower part of the rail and the tunnel rock bed. Therefore, in this study, it is necessary to analyze the concrete crack structure according to the depth of the existing tunnel and the modified tunnel section, and to evaluate the adequacy of the required thickness of the tunnel floor concrete for securing the crack stability of the concrete.

• Journal of the Korean Society for Railway
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• v.10 no.5
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• pp.457-462
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• 2007

An application of concrete track is being activity processed for the construction of Korean railroad. The concrete track has an advantage to decrease the maintenance fee, but is very difficult to control the settlement of ground and embankment consisting of substructure of concrete track below the allowable settlement level. This is the reason why the measurement and evaluation of both ground and embankment settlement before the installation of the concrete track is very important. One ground, a lower subgrade, and five surface settlements are measured to understand the settlement behavior of ground and embankment settlement. The period to measure settlements was more than 1 year after the completion of embankment. In this test site, ground settlement was over during the construction of embankment, but the embankment settlement are being continuously proceeded after the completion of embankment. The settlement velocity gradually is slowing down as time goes by. This paper also analysed the reasons of abrupt settlement increase and concluded that the rainfall was one of the important reason to increase settlement rate.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.625-631
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• 2023

This study proposes an analysis model that can reflect the actual behavior of the rail floating track, and the most reasonable model was analyzed through field measurement and numerical analysis. It was analyzed that the current design theory analysis results of rail floating tracks were different from the field measurement results and were not suitable to reflect the actual behavior. In the rail floating track, it was analyzed that the subsidence of the point directly affects the total displacement rather than the displacement due to the bending of the rail. As a result of numerical analysis, it was analyzed that the analysis result of the proposed model, which is a parallel arrangement spring model that does not have a support point directly below the rail, reflects the actual behavior. The analysis model presented in this study can be used to predict track behavior when designing and maintaining rail floating tracks in the future.