• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1312-1319
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• 2006

Several countries including Korea, Japan and European countries have reached the stage of planning, constructing their high-speed railway systems. High-speed train will become a key tool for intercity passenger transportation. Before that, safety of high-speed train must be secured. It is connected directly with track. The track is composed of ballast, tie, fastening and rail. Also, the fastening system makes tie and rail connect. In this case of the railway bridges used concrete slab track, the deflection of the bridge cause uplife of the rail at the areas between segments. In the structural analysis about it, stiffness of the fastening systems has been assumed. Therefore, use of the stiffness according to an experimental study needs. In this study, the stiffness values of various types of fastening systems are determined by the experiment and the structural behavior of fastening system is analyzed.

• 한국도로학회논문집
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• 제17권1호
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• pp.83-90
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• 2015

PURPOSES : The purpose of this study is to investigate the relationship between the crack propagation depth through a slab and crack width movement in continuously reinforced concrete slab systems (CRCSs). METHODS : The crack width movements in continuously reinforced concrete pavement (CRCP) and continuously reinforced concrete railway track (CRCT) were measured in the field for different crack spacings. In addition, the crack width movements in both CRCP and CRCT were simulated using finite element models of CRCP and CRCT. The crack width movements, depending on the unit temperature change, were obtained from both the field tests and numerical analysis models. RESULTS : The experimental analysis results show that the magnitudes of the crack width movements in CRCSs were related to not only the crack spacing, but also the crack propagation depth. In CRCP, the magnitudes of the crack width movements were more closely related to the crack propagation depths. In CRCT, the crack width movements were similar for different cracks since most were through cracks. If the numerical analysis was performed to predict the crack width movements by assuming that the crack propagates completely through the slab depth, the predicted crack width movements were similar to the actual ones in CRCT, but those may be overestimated in CRCP. CONCLUSIONS : The magnitudes of the crack width movements in CRCSs were mainly affected by the crack propagation depths through the slabs.

• 한국전산구조공학회논문집
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• 제34권6호
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• pp.363-370
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• 2021

본 연구는 이러한 단점을 보완하기 위해 철근을 대체하여 내산화성과 전기저항이 높은 GFRP 보강근을 적용한 도상슬래브의 최적변수해석을 수행하였다. 철도 궤도슬래브에 적용되는 철근은 열차 운행 중 신호전류의 손실을 일으켜 열차의 안정성을 저해하며, 철근의 부식으로 내구성이 저하될 수 있다. GFRP 보강근의 직경 및 배근 개수 변화가 전체 콘크리트 도상슬래브의 휨강도 및 균열제어에 미치는 영향을 유한요소 변수해석을 통하여 상세분석하였다. 해석 결과, GFRP 보강근의 직경 및 배근을 합리화하여 제안하였으며 이러한 경우 기존 배근보다 더욱 경제적인 단면을 도출할 수 있음을 알 수 있었다. 본 연구로부터 도출된 결과는 향후 GFRP 보강근을 적용하여 도상슬래브를 설계하는 경우 보다 합리적이고 경제적인 단면을 산정할 수 있는 가이드라인이 될 수 있을 것으로 기대된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3172-3179
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• 2011

Several materials using polymer-portland-cement concrete have developed to have not only strength of attachment with body, but also waterproof function and strong anti-sodium chloride properties. Especially, in case of railway, unlike other public transportation, it is very difficult to doing the repair and reinforcement work of structure during service time. Therefore, the development and study of materials having characteristics of structural strength, unification behavior with body, and resistance of crack are very important. Accordingly, the characteristic of material of polymer based concrete is indicated compared with the experiment and analysis through this study, and suggested application to railway tunnel, bridge, and concrete track structure.

• 산업기술연구
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• 제25권B호
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• pp.3-10
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• 2005

Since in 1970, the length of concrete pavements(JCP, JRCP and CRCP) are growing rapidly at both of main highways and local roads. Many of them are deteriorated and old enough to be repaired or replaced. The pavement is more important than the other infrastructures and it is very difficult to go around or block the traffic during the rehabilitation. The very-early strength latex-modified concrete(VES-LMC)may offer the advantages of high-early-strength, higher flexural strength, higher bond strength, and improved durability. The VES-LMC could be used at a kind of fast track ofr early opening to the traffic after 3 hours of concrete placement. The installation of VES-LMC overlay at Jung-Boo highway was successfully done from April 28 to 29, 2005. The traffic was closed at 07:00 PM and opened to traffic at 08:30 AM. The compressive and flexural strength of VES-MC were more than 28MPa, 6.2MPa after 4 hours, respectively.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.69-70
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• 2014

For the curved concrete track construction of 2018 winter Olympic sliding center in Pyeongchang, in this study proposed the digital fabrication technology using CNC. This method can control the 3D geometries of the curved concrete structure based on the digital design. Conventional method generates the construction errors because this method fabricates many temporary zig bar using 1:1 full size drawing for install frozen pipes and sets up each zig bars at the construction site. Propose method is effective to ensure the precise fabrication and construction of zig bars. Also this method can eliminate errors of the frozen pipes position and curved concrete construction.

• International Journal of Railway
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• 제7권3호
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• pp.85-89
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• 2014

The use of pozzolanic materials in concrete mixtures can enhance the mechanical properties and durability of concrete. By reactions with pozzolanic materials and calcium hydroxide in cement matrix, calcium-silicate-hydrate (C-S-H) increases and calcium hydroxide decreases in cement matrix of concrete. Consequently, the volume of solid materials increases. The pozzolanic particles also fill spaces between clinker grains, thereby resulting in a denser cement matrix and interfacial transition zone between cement matrix and aggregates; this lowers the permeability and increases the compressive strength of concrete. Moreover, the total contents of alkali in concrete are reduced by replacing cements with pozzolanic materials; this prevents cracks due to alkali-aggregate reaction (AAR). In this study, nanosilica is incorporated in cement pastes. The differences of microstructural compositions between the hydrated cements with and without nanosilica are examined using nanoindentation, XRDA and $^{29}Si$ MAS NMR. The results can be used for a basic research to enhance durability of concrete slab tracks and concrete railway sleepers.

• 한국전산구조공학회논문집
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• 제29권2호
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• pp.169-177
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• 2016

슬라이딩 궤도는 콘크리트 궤도와 교량 바닥판 사이에 저마찰 슬라이드층을 두어 레일신축이음장치와 같은 특수 장치를 적용하지 않고도 궤도-교량 상호작용 효과를 효과적으로 저감시킬 수 있는 새로운 궤도 시스템으로 개발되고 있다. 이 논문에서는 장경간 교량에 슬라이딩 궤도와 레일신축이음장치를 각각 적용한 경우에 대하여 궤도-교량 상호작용해석을 수행하고 그 결과를 비교 검토하였다. 대상교량은 상호작용 효과를 극대화하기 위하여 9경간 연속 PSC교와 2경간 연속 강합성교를 포함하며, 총 연장 1,205m, 최대 고정지점간 거리 825m인 장경간 교량을 선정하였다. 해석결과 슬라이딩 궤도는 레일신축이음장치를 적용한 경우보다 레일 부가 축력이 더 작은 것은 물론, 지점부에 재하되는 수평 반력 또한 작게 나타나 궤도-교량 상호작용 저감 효과가 뛰어난 것으로 확인되었다. 반면 슬라이딩 궤도는 온도하중에 의해 높은 슬래브 축력이 발생되므로, 궤도 설계 시 슬래브 축력에 대한 단면 설계에 주의를 기울일 필요가 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.406-411
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• 2011

An active application of tram is being expected in Korea in the near future. For the tram operation in urban area, the embedded rail tracks where rails are completely embedded with pavements is required. When the embedded rail track is constructed on fine-grained subgrade soil, excessive cumulative plastic settlements due to repetitive tram road may occur. In this study, repetitive load tests were carried out to evaluate the accumulative plastic settlements of subgrade soils underneath embedded rail tracks. Two real-scale track specimens of 5 m lengths were constructed considering the maximum cant of a curved line. Repetitive tram loads of three million times were applied to the tracks in 5 Hz frequency. The accumulating patterns of plastic settlements were analyzed. Tram load distributing effects of the concrete slabs were also evaluated using the measured data of earth pressures cells that were installed underneath track. Also the measured settlements were compared with the estimated settlements calculated from an existing experimental equations, and its validity is discussed.

• 한국철도학회논문집
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• 제13권1호
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• pp.78-83
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• 2010

포장궤도에서는 프리팩 콘크리트방식으로 도싱자갈을 충전층의 골재로 활용한다. 골재의 가장 중요한 조건은 모르터와의 부착력이며 이를 위하여 표면의 불순물을 최대한 제거하여야 한다. 국내에서 개발한 포장궤도 공법에서는 기존의 수세척방식을 대체하는 친환경 건식세척기술을 개발하였다. 건식세척은 직경 0.3~0.5mm 내외로 파쇄한 경질 재료를 고압으로 분사시켜 골재 표면을 박피시키는 방식이다. 본 논문에서는 블라스팅기술의 세척 효율을 향상시키기 위한 방안으로 현재 운용중인 장비조건하에서 분사 재료 및 시간 별 골재 잔입자 함량, 염화물 함유량, LA마모율, 압축강도시험 등을 실시하여 가장 효율적인 세척 재료 및 공정을 제시하고자 하였다.