• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2006.06b
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• pp.163-170
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• 2006

Together with the trend of enhancement in domestic industrial development and economic progress due to import and export, the demand for construction of the roads, bridges, especially port facilities, and several coastal protection and ocean structures is increasing rapidly. MOMAF of Korean Government is driving construction of 9 new ports and renovation of the existing fishery ports. Among these structures most of bridge base, wharves, dolphins, quays, and jetties are being newly built of steel or concrete pile. As the base, supporting bulkheads, and piles are underwater after construction, it is difficult to figure out the status of structures and not enough to get maintenance and strengthen the structures. Every year, moreover, these works suck the government budget due to higher incomplete maintenance expense for protection from corrosions of structures and increased underwater construction period. For the purpose of cutting down the expense of government budget, it is necessary to extend the life cycle of the existing structures. Therefore, we developed a new method for maintenance of submerged structures near the waterline by allowing dry work environment with the floating caisson. The method shows easy to move around the working area and handle. It also showed not only a significant reduction maintenance expenses and time for anti-corrosion work but also better protection. This will be a milestone to reduce the maintenance and construction expenses for the shore and water structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.42-48
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• 2017

When concrete structures expose to fire, the structures were damaged accompanied with degradation of material properties of concrete. In order to determine the reuse of fire-damaged concrete structures, it is needed a careful determination considering conditions of fire damage, such as exposure temperature and exposure time, and also potential to restore fire damage. This study investigates on the evaluation of residual material properties of fire-damaged concrete under different post-fire curing regimes. An experimental study was performed on concrete samples to measure the dynamic elastic modulus by the impact resonance vibration method. Upon the experimental results, the evidence of restoration of material properties was confirmed on specific post-fire curing regimes, higher humidity conditions. Additionally, a correlation analysis was performed on the dynamic elastic modulus with the tensile strength for identifying the effects of post-fire curing regimes on both material properties of fire-damaged concrete.

• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.781-791
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• 2015

Dam risk analysis requires a systematic process to ensure that hydrologic variables (e.g. precipitation, discharge and water surface level) contribute to each other. However, the existing dam risk approach showed a limitation in assessing the interdependencies across the variables. This study aimed to develop Bayesian network based dam risk analysis model to better characterize the interdependencies. It was found that the proposed model provided advantages which would enable to better identify and understand the interdependencies and uncertainties over dam risk analysis. The proposed model also provided a scenario-based risk evaluation framework which is a function of the failure probability and the consequence. This tool would give dam manager a framework for prioritizing risks more effectively.

• Korean Journal of Construction Engineering and Management
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• v.7 no.4 s.32
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• pp.69-77
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• 2006

In recent years, there has been more reconstruction and redevelopment of apartments rather than efforts to consider alternative to extend the life time of the apartments. It is essential to try to develop ways to adequately maintain and to use the apartment facilities efficiently in order to preserve earth environment and the limited resource. However, tacking research on the effects obtained through remodelling and maintenance have interfered with the vitalizing of the market. The objective of this study is to propose criterions and methods with which to evaluate adequacy of maintenance management. A survey was performed to investigate important maintenance methods in order to obtain advices that can smoothly progress improve apartment maintenance management. This study applied AHP(Analytical Hierarchy Process) methods for reasonable maintenance in apartment. Through this study, the flow of apartment maintenance market is elevated to reaching the level in advanced nation.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.105-105
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• 2017

최근 우리나라에서는 국지성호우로 인해 발생하는 돌발홍수에 방어하지 못하는 소규모 저수지에 대한 붕괴사고가 빈발하고 있다. 붕괴된 저수지를 살펴보면, 대체적으로 규모가 작아 체계적인 안전관리가 이루어지지 않거나 경과연수가 50년 이상인 필댐(fill dam) 형식으로 축조된 노후저수지로서 갑작스러운 홍수를 대응하는데 있어 매우 취약한 상태이다. 체계적으로 운영되는 대형댐에 비해 축조기간이 오래된 소규모 저수지의 경우, 저수지에 대한 수문학적 정보가 거의 없거나 미계측되어 보수보강이 필요한 저수지를 선정하거나 정량적인 위험도를 분석하는데 매우 어려운 실정이다. 이러한 이유로 본 연구에서는 노후된 소규모 저수지에 대한 수문학적 파괴인자들을 선정하여 Bayesian Network기반의 소규모 저수지 위험도 분석 모형을 구축하였다. 구축된 모형을 기준으로 고려될 수 있는 다양한 위험인자 및 이들 인자간의 연관성을 평가하였으며, 각각의 노드에 파괴인자를 노드로 할당하여 소규모 저수지의 위험도를 분석하였다. Bayesian Network기법의 도입으로 불확실한 상황을 확률로 표시하고, 복잡한 추론을 정량화된 노드의 관계로 단순화시켜 노드의 연결 관계로 표현하였다. 본 연구에서 제안된 모형은 노후된 소규모 저수지의 수문학적 위험도를 정량으로 분석하는 모형으로서 활용성이 높을 것으로 기대된다.

• Korean Architects
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• no.8 s.388
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• pp.85-91
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• 2001

10년도 넘었을까 모처럼 유럽을 여행할 기회가 있었다. 우리나라는 온 국토가 공사장이나 진배없던 시절이라 그곳의 풍경이 오히려 이채로웠다. 자동차를 타고 한참을 가야 그것도 별로 크지 않은 공사장을 볼 수 있었고, 그나마 신축공사 보다는 오래된 건물을 보수하는 것들이 더 많았다. 더구나 희한한 것은 대로에 면한 고색 창연한 건물의 외벽만을 텔레비전 세트처럼 남겨두고 그 뒤편에서는 전혀 새로운 공사를 하는 것도 눈에 들어왔다. 조상들의 유적을 외관만이라도 보존하도록 법제화되었으므로 여기저기 떨어져 위치한 100년도 넘은 집에다 따로따로 최신형 공작기계를 설치한 공장에서 제품을 생산하는 비능률을 감수하는 것도 볼 수 있었다. 물론 변두리 신시가지에서는 현대 감각이 물씬한 건물도 신축하고 있었는데, 대체로 리모델링 사업규모가 전체 건축 물량의 50% 정도는 될 것이라는 설명이었다. 필자는 그때 우리도 머지 않아 그런 시절이 도래할 것이라는 확신이 있었다. 더구나 그들의 건물들이 100년 이상을 버티는데 반하여 우리네 것들은 수명이 고작 20~30년 밖에 되지 못할 정도로 부실하기 때문이다. 그때부터 기존 건물의 내력 부족분을 보완하고 용도를 변경하거나 증축을 할 때 어떤 방법이 합리적일까 하는 것에 관심을 가지고 연구하게 되었다. 바닥 슬래브나 보를 잘라버리거나 새로 덧붙이기도 하고 심하면 기둥을 솎아낼 필요가 있을 수도 있다. 그러나 유감스럽게도 대부분의 경우는 그동안 열심히 고안한 방식을 실무현장에 적용할 수 있도록 받아들이는 당사자가 별로 없었다. 첫째 이유는 처음하는 일이라 말하자면 겁이 난다는 것이고, 둘째로는 새로운 방식을 믿고 시행하려 해도 실제로 책임지고 시공하겠다고 나서는 업체를 만날 수 없어서였다. 그래서 그동안 설계뿐만 아니라 시공까지 일일이 간섭하여 어렵게 시행했던 현장 경험들을 소개하여 앞으로 비슷한 조건을 만날 경우 참고할 수 있게 한다. 우선 기둥을 솎아 내는 것을 알아보고 앞으로 기둥, 보, 슬래브, 기초 등의 새로운 보강방법을 소개하고자 한다.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.553-558
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• 2000

In this study, a numerical simulation that can effectively predict the interfacial fracture behavior in repaired structures is developed using the axial deformation link elements. In repaired structures, concrete and interface are considered as quais-brittle materials, and steel plate as a repair material and reinforcement are modeled as elasto-plastic materials. The behavior of repaired reinforced concrete structures under flexural loading conditions is numerically simulated, and compaired with experimental results. The strengthening effect according to the length and thickness of the repair material is studied and rip-off, debonding and rupture failure mechanism of interface between substrate and repair materials are detected. It is shown that the interface properties affect on the mechanical behavior of repaired structures. Therefore, the developed numerical method using axial deformation link elements can be used for determining the strengthening effects and failure mechanism of repaired structures.

• Journal of Korean Society of Disaster and Security
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• v.5 no.1
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• pp.43-47
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• 2012

The asset management of infra facilities is a total framework for finally supporting a safe and comfortable service, which includes functions of supporting evaluation of condition and performance of infrastructures, making the decision method of repair or rehabilitation of deteriorated facilities, and lengthening the life cycle of structure through the decision of adequate cost and time of repair or reinforcement. In the range of the asset management, organization, human, the target, and information & data of company are included. Therefore, in this paper, appling the method of asset management analysis to the infra structures, the process of the risk assesment using BRE (Business Risk Exposure) and the basis of consisting ORDM (Optimized Renewal Decision-Making) are expressed.

• 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 Navigation and Port Research
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• v.30 no.6 s.112
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• pp.447-455
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• 2006

Together with the trend of enhancement in domestic industrial development and economic progress due to import and export, the demand for construction of the roads, bridges, especially port facilities, and several coastal protection and ocean structures is increasing rapidly. MOMAF of Korean Government is driving construction cf 9 new ports and renovation cf the existing fishery ports. Among these structures most of bridge base, wharves, dolphins, quays, and jetties are being newly built cf steel or concrete pile. As the base, supporting bulkheads, and piles are underwater after construction, it is difficult to figure out the status of structures and not enough to get maintenance and strengthen the structures. Every year, moreover, these works suck the government budget due to higher incomplete maintenance expense for protection from corrosions cf structures and increased underwater construction period. For the purpose cf cutting down the expense cf government budget, it is necessary to extend the life cycle of the existing structures. Therefore, we developed a new method for maintenance of submerged structures near the waterline by allowing dry work environment with the floating caisson. The method shows easy to move around the working area and handle. It also showed not only a significant reduction of maintenance expenses and time for anti-corrosion work but also better protection This will be a milestone to reduce the maintenance and construction expenses for the shore and water structures.