• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.466-471
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• 2011

본 연구에서는 장대 현수교 주케이블의 가설시 선형관리를 위한 기초적 연구를 수행하였다. 우선, 포물선 요소 및 탄성현수선 요소의 정식화 과정을 검토하고, 각 요소의 적용에 따른 현수교 주케이블 완성계 및 가설계의 형상, 장력, 무응력장 등을 비교검토 하였다. 또한, 탄성현수선의 적용시 주케이블 가설계의 setback량 산정 방법을 제시하였으며, 이에 따른 산정 결과를 유한요소해석 결과와 비교검토 하였다. 최종적으로, 주케이블 가설계의 중앙경간 새그량 변화에 따른 탑정 새들부에서의 미끌림 안정성에 대한 민감도 해석을 수행할 예정이다.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.77-80
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• 2005

Lightweight concrete is known for its advantage of reducing the self-weight of the structures, reducing the areas of sectional members as well as making the construction convenient. Thus the construction cost can be saved when applied to structures such as long-span bridge and high rise buildings. However, the lightweight concrete requires specific mix design method that is quite different from the typical concrete, since using the typical mix method would give rise the material segregation as well as lower the strength by the reduced weight of the aggregate. In order to avoid such problems, it is recommended to apply the mix design method of self-compacting concrete for the lightweight concrete. Experimental tests were performed as such compressive strength, dry shrinkage and carbonation of high strength lightweight self-compacting concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.455-458
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• 2005

The Steel-Confined Prestressed Concrete Girder(SCP Girder) has been developed, which maximizes structural advantages of components (concrete, steel plate and tendon) and can be used to construct the middle or long span bridge with low-height girder. And recently, a continuous beam type of SCP Girder has been being developed to decrease size and self weight of girder in comparison with a simply-supported type. In this study, as part of developing the continuous beam type of SCP Girder, a new type of anchorage zone is proposed in order to address tendons effectively and decrease section size of SCP Girder efficiently. And also, the experimental test was carried out using a real scale specimen to examine the behavior of proposed anchorage zone.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.564-569
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• 2009

Due to the uneasy controllable qualities of the substructures such as pile and foundation, which are laid on underground, geotechnical engineers have applied conservative criteria to them. Therefore, the specification criterion of cast-in-situ concrete pile, which allows only one fourth of the compressive strength of structural capacity, has forced geotechnical designers to consider the most uneconomical design regardless of satisfying the grade of quality-control, required performance, construction cost and so on. Thus, in this study, we proposed the less conservative criteria on the strength of concrete pile, based on the experimental testing results of cast-in-situ concrete piles.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.437-440
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• 2010

연육 연도교에 주로 건설되는 초장대교량은 시설물 특성상 이용객들의 대피공간이 제약받고 태풍, 해일 등 자연재해에 노출이 많기 때문에 다른 공공시설물보다 재난에 취약한 구조물이다. 최근 공공시설물의 건설동향은 구조물이 장대화 되어가고 있어 재난 발생시 예상 위험이 점점 더 커지고 있다. 본 연구는 국내외 장대교량의 재난사고와 재난관리 사례연구를 통해 초장대교량에서 관리되어야 할 재난을 정의하였다. 초장대교량의 재난은 자연재해와 인적재해로 구분할 수 있는데, 자연재해로는 안개, 강설, 결빙, 강풍, 지진, 해일이 있으며 인적재해로는 교통사고, 화재, 테러, 선박충돌, 구조물 파괴 및 재료열화가 있다. 또한 초장 대교량에서 발생 가능한 모든 사고의 잠재가능성을 분석하여 가상의 재난관리 시나리오를 작성하였다. 이 시나리오는 예방, 대비, 대응 및 복구로 구분되는 관리단계별 실행계획 수립에 기초를 제공하게 될 것이다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.429-431
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• 2010

태풍 및 지형에 대한 컴퓨터 시뮬레이션과 기상관측자료에 대한 분석을 통해 장대교량의 가설위치에서 발생할 수 있는 풍환경을 분석하고 설계풍속을 산정하였다. 설계풍속의 산정은 내풍 설계를 위한 하중을 결정하는 과정으로 내풍설계의 기본이 되는 부분이다. 풍환경 분석 과정은 Monte Carlos(이하 MC) 태풍 시뮬레이션 분석, Gumbel 극치분석, CFD 지형효과 분석으로 구성된다. MC 태풍시뮬레이션 분석을 통해 태풍시기(6~10월)의 재현주기별 강풍발생빈도를 도출하였다. Gumbel 극치분석을 통해 인근의 기상관측자료로부터 전년도에 대한 재현주기별 강풍발생빈도를 도출하였다. CFD 지형효과 분석을 통해 분석대상지역의 주변지형으로 인한 풍속증감효과를 분석하였다. 각 결과를 종합하여 보수적인 재현주기별 설계풍속을 산정하였다.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.57-62
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• 2013

Aerodynamic characteristics of cross section shape is an important parameter for the wind response and structural stability of long span bridges. Numerical simulation methods have been introduced to estimate the aerodynamic characteristics for more detailed flow analysis and cost saving in place of existing wind tunnel experiment. In this study, the computational fluid dynamics(CFD) simulation and large eddy simulation( LES) technique were used to estimate lift, drag and moment coefficients of four cross sections. The Strouhal numbers were also determined by the fast Fourier transform of time series of the lift coefficient. The values from simulations and references were in a good agreement with average difference of 16.7% in coefficients and 8.5% in the Strouhal numbers. The success of the simulations is expected to attribute to the practical use of numerical estimation in construction engineering and wind load analysis.

• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.55-62
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• 2007

The structural safety of long span bridges such as suspension bridges is smaller under the construction stage than in the completion. But the importance of construction sequences has been neglected in most of safety check programs. On this study is developed the structural analysis method of suspension bridges considering construction sequences and structural analyses are performed by step by step during construction. This can be used to determine the safest erection method. The results shows that the more critical structural behavior appears under construction than after completion.

• Wind and Structures
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• v.28 no.2
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• pp.129-140
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• 2019

Accurately simulating the wind field of large-scale region, for instant urban areas, the locations of large span bridges, wind farms and so on, is very difficult, due to the complicated terrains or land surfaces. Currently, the regional wind field can be simulated through the combination of observation data and numerical model using observation-nudging in the Weather Research and Forecasting model (WRF). However, the main drawback of original observation-nudging method in WRF is the effects of observation on the surrounding field is fully mathematical express in terms of temporal and spatial, and it ignores the effects of terrain, wind direction and atmospheric circulation, while these are physically unreasonable for the turbulence. For these reasons, a spatial correlation-based observation-nudging method, which can take account the influence of complicated terrain, is proposed in the paper. The validation and comparation results show that proposed method can obtain more reasonable and accurate result than original observation-nudging method. Finally, the discussion of wind field along bridge span obtained from the simulation with spatial correlation-based observation-nudging method was carried out.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.383-392
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• 2018

This study investigated the change of additional axial stress of rail and reaction force at bridge bearings due to the track-bridge interaction when laying CWR on non-ballasted railway bridges including truss bridges with relatively long span. According to the results of the present study, additional axial stresses of rail and reaction forces at bridge bearings showed a large increase when CWR is installed on the non-ballasted railway bridge. The additional axial stress of rail can be acceptable if sufficient lateral resistance can be obtained. However, if the reaction force increases, there is a risk of damage of the bearing or pier, and therefore, it is necessary to take measures to mitigate the reaction force. It is found that additional axial stress of rail decreases when considering the frictional resistance of the bridge movable support, but its effect on the bearing reaction force is very small. On the other hand, when the longitudinal track restraint decreases, both additional axial stress of rail and bearing reaction force are reduced to a large extent. Also, when the ZLR fastening devices are applied to the region where the additional axial stress of rail is highest, bearing reaction force as well as additional axial stress of rail greatly decreased. Therefore, the application of ZLR fastening devices with the reduction of the longitudinal track restraints is very effective for installing CWR on non-ballasted railway bridges.