• Structural Engineering and Mechanics
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• 제63권6호
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• pp.713-723
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• 2017

As a new type of ballastless track, longitudinal continuous slab track (CST) has been widely used in China. It can partly isolate the interaction between the ballastless track and the bridge and thus the rail expansion device would be unnecessary. Compared with the traditional track, CST is composed of multi layers of continuous structures and various connecting components. In order to investigate the performance of CST on a long-span bridge, the spatial finite element model considering each layer of the CST structure, connecting components, bridge, and subgrade is established and verified according to the theory of beam-rail interaction. The nonlinear resistance of materials between multilayer track structures is measured by experiments, while the temperature gradients of the bridge and CST are based on the long-term measured data. This study compares the force distribution rules of ballasted track and CST as respectively applied to a long span bridge. The effects of different damage conditions on CST structures are also discussed. The results show that the additional rail stress is small and the CST structure has a high safety factor under the measured temperature load. The rail expansion device can be cancelled when CST is adopted on the long span bridge. Beam end rotation caused by temperature gradient and vertical load will have a significant effect on the rail stress of CST. The additional flexure stress should be considered with the additional expansion stress simultaneously when the rail stress of CST requires to be checked. Both the maximum sliding friction coefficient of sliding layer and cracking condition of concrete plate should be considered to decide the arrangement of connecting components and the ultimate expansion span of the bridge when adopting CST.

• 한국구조물진단유지관리공학회 논문집
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• 제20권2호
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• pp.110-121
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• 2016

구조 형식이나 공법의 선정, 유지보수 시기, 보수방법의 결정 등의 의사 결정에서 수명주기비용(life cycle cost, LCC)의 평가가 중요하다. 철도 궤도구조의 경우 초기시공비 뿐 아니라 유지보수비가 총 비용의 상당 부분을 차지하고, 특히 자갈궤도일수록 그 비율은 더욱 높으므로 수명주기비용 평가의 필요성이 더욱 높다. 이 연구에서는 궤도 구조 형식, 연간 통행량, 축중, 열차 속도, 곡선 비율, 구조물(교량, 터널) 비율 등 다양한 설계변수를 고려할 수 있는 LCC 산정 모델을 개발하고, 각 비용의 산정에 필요한 기초 자료를 제시하였으며 구축된 모델과 자료를 바탕으로 주요 설계변수에 따른 고속철도 자갈궤도와 콘크리트궤도 LCC의 변화 경향을 분석하고, 이로부터 궤도 LCC 분석에 있어서의 고려해야 할 주요 변수를 검토하였다. 검토 결과 자갈궤도는 교체 및 운영 비용의 비중이 콘크리트궤도에 비해 현저히 높았으며, 연간 통행량과 자갈 탬핑 주기가 자갈궤도의 LCC에 가장 큰 영향을 미치는 것으로 나타났다. 반면 콘크리트궤도는 초기 시공비의 비중이 현저히 높았고, 연간 통행량이나 열차속도, 축중 등에 상대적으로 영향을 적게 받는 것으로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1002-1008
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• 2011

Turnout is a mechanical installation enabling railway trains to be guided from one track to another at a railway junction. there are classified variously according to rail type, sleeper type, fastening system, track type. Construction of concrete track are on the increase recently to secure the safety of track structure as well as to reduce the maintenance cost. SFC fastening system used the plain track a lot and for those reasons, The fast clip turnout demand growing to improving efficiency of the maintenance cost by unification of fastening clip on whole line. in this study is about development of the fastening system for new turnout using fast clip. this fastening system assembled elasticity pad underneath a base plate. its can change stiffness how to adjust contact surface area of elasticity pad Developed fastening system have passed test according to rule of KRS-TR0014-09R (rail fastening system) and Performance Certification by KR.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2057-2063
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• 2011

Recently, concrete slab track is mostly used to satisfy requirements for safety of high-speed train operation and economical efficiency of maintenance. Due to structural characteristics of ballast track structures, roadbeds under the ballast experience a state of high stress. In case of slab track structures, however, its roadbeds place on a condition of low stress less than roadbeds of ballast track structures as increasing of the loading area. In this study, vertical earth pressure under slab track structures was investigated through real-scale loading tests and theoretical analysis to compare with each other.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.475-480
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• 2001

In this study, a empirical equation which can be feasibly used to evaluate minimal track buckling strength without exact numerical analysis is presented. Parameter studies we carried out to investigate the effects of the individual factor on buckling strength. In order to simulate track buckling in the field as precisely as possible, a rigorous buckling model which accounts for all the important parameters is adopted. A empirical equation for prediction of minimal track buckling strength is derived by taking nonlinear regression of data which are obtained from numerical analyses. Its characteristics and applicability are investigated by comparing the results by the presented equation with the one by the equation which was presented in japan, and is frequently using in korea when designing track structure.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.539-545
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• 2009

KTX trains which began passenger service between Seoul and Busan in April 2004 have gained very high evaluation for their safe operation. Track is one of the most important means to keep KTX safety, it has not been a fail of safe structure. The track failure during operation may lead to a severe accident. So, it is to be verified the confidence of track maintenance management on the high speed line. This paper would like to find a track deformation trend through a comparative analysis on actual measurement data at these times. It discusses the effect of cyclic dynamic load at welding part. KTX dynamic impact load was measured in accordance with a rail surface irregularity and analyzed some track irregularities according to the condition of rail profile at welding part in the Gyeongbu high speed line.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.561-566
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• 2003

In this paper, a numerical method for evaluating the efficiency of vibration reduction of substructure under floating slab track is developed for optimal design of floating slab track. The equation of motion for train and track interaction system is derived by applying compatibility condition at the contact points between wheels and rails. The train is modelled by 3-masses system and the track by continuous support beam system. Numerical analyses are carried out to investigate the effects of train speed, stiffness and damping of slab-pad, and track irregularity upon vibration reduction in substructure under the track.

• 한국철도학회논문집
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• 제8권4호
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• pp.354-360
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• 2005

The railway track and the substructures constructed in the field test section of Kyongbu High Speed Line are the structures for HSL, for the first time designed and constructed by domestic technical group. It is very important to verify the local design criteria and specifications for these structures and also to assure the recordings for vibration or deflection produced on the essential parts of the structures. The study to verify the high-speed railway track performance and to ensure the run in safety on the track in curved section during the KTX run. Finally, the conclusion are drawn as follows. The measuring values of the deflection effort of the rail and displacement for verifying the track performance in the field test section of Kyoungbu HSL satisfy the criteria of the foreign countries (Japan and Germany). The measured value for the wheel load and the presumed value show the consistent tendency. The wheel loads of the exterior and interior of the rails at the speed superior to 300km/h are measured same. Finally, the comparison between the theoretical value presented during the verification of the derailment to evaluate the safety of the train run at the time of the detailed design of the track and the measured value in the field shows that the correct design of track structure was applied.

• 대한토목학회논문집
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• 제42권1호
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• pp.95-105
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• 2022

최근 공사규모의 대형화, 복잡화 등으로 토목, 건축, 기계 등의 복합공종으로 구성된 공사들은 공기절감을 위해 패스트트랙(Fast Track) 방식으로 진행되는 사례가 많으며, 패스트트랙 방식에서는 적정 단계구분이 전체 프로젝트의 공기 책정에 중요한 사안이다. 본 연구에서는 복합공종으로 구성된 건설공사가 패스트트랙으로 진행될 때 적용할 수 있는 단계구분 방식을 제시하고 있다. 이를 위해 연구에서는 토목, 건축공사로 구성된 4개의 축구전용경기장 공사를 적용 사례로 분석하여 세분화된 공정분류체계(Work Breakdown Structure, WBS)를 통해 주요 단계별 공정 구분에 의한 일정표를 분석하고, 5가지 시안을 적용하여 패스트트랙 단계구분의 적정성을 분석한다. 분석된 시안중에서 최소 공기를 갖는 시안에 대하여 패스트트랙 단계구분 및 단계별 주요 공정의 구성 모형을 제시하였다. 이러한 방법론은 패스트트랙이 적용되는 유사한 규모의 대형 복합공사에서 패스트트랙 적용 시에 적정 단계 구분과 단계별 공정 구성 체계에 활용성을 가질 수 있다.

• 한국정보전자통신기술학회논문지
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• 제12권6호
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• pp.666-671
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• 2019

소형 드론에서 사용되는 FC(Flight Controller)는 사용하는 MCU가 대형 드론과는 달라서 복잡한 연산을 수행하지 않아도 되는 단순한 구조로 개발되었다. 또한 소형 드론의 균형제어는 복잡한 필터를 이용하는 Kalman Filter나 연산수가 상대적으로 많은 Complementary Filter를 이용한 방법보다는 좀 더 단순하고 간단해야 할 필요가 있다. 따라서 본 연구에서는 이에 적합한 방법으로 동작하는 Two-Track 제어를 이용하여 효과적으로 소형 드론에서도 균형제어가 이루어질 수 있도록 하는 방법을 제안하였다. 이 방법은 긴 시간의 변화량에 대한 데이터 처리를 통해 정확한 보정을 해주는 장점이 있는 Acceleration 센서와 짧은 시간의 변화량에 대한 데이터 처리를 통해 드론 균형을 유지해주는 Gyroscope 센서가 드론의 불균형에 대해 적응적으로 동작하여 단순한 구조와 적은 연산량으로도 효율적인 균형을 유지해주는 시스템이다. Two-Track 제어를 이용하여 100회 이상 반복하여 드론 비행을 실험한 결과 대부분 안정적인 동작을 수행하였으며, 갑자기 발생하는 급격한 바람의 영향에는 아직도 정상상태로 진입하는데 어려움이 있는 것을 제외하면 98% 이상 정상상태 동작을 유지하였음을 확인하였다.