• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.4
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• pp.109-120
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• 2007

In this study, a bridge maintenance system is developed to generate performance-based optimum maintenance strategy by considering the life-cycle cost. A multi-objective combinatorial optimization problem is formulated to generate a tradeoff maintenance scenarios which satisfies the balance among the conflicting objectives such as the performance and cost during the bridge lifetime and a genetic algorithm is applied to the system. By using the developed program, this study proposes a process of optimum maintenance scenario applying to the steel girder bridge of national road. The developed system improves the current methods of establishing the bridge maintenance strategy and can be utilized as an efficient tool to provide the optimum bridge maintenance scenario corresponding to the various constraints and requirements of bridge agency.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.167-174
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• 2007

This study proposes a practical and realistic method to establish an optimal lifetime maintenance strategy for deteriorating bridges by considering the life-cycle performance as well as the life-cycle cost. The proposed method offers a set of optimal tradeoff maintenance scenarios among other conflicting objectives, such as minimizing cost and maximizing performance. A genetic algorithm is used to generate a set of maintenance scenarios that is a multi-objective combinatorial optimization problem related to the and the life-cycle cost and performance as separate objective functions. A computer program, which generates optimal maintenance scenarios, was developed based on the proposed method. The subordinate relation between bridge members has been considered to decide optimal maintenance sequence. The developed program has been used to present a procedure for finding an optimal maintenance scenario for steel-girder bridges on the Korean National Road. Through this bridge maintenance scenario analysis, it is expected that the developed method and program can be effectively used to allow bridge managers an optimal maintenance strategy satisfying various constraints and requirements.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.259-268
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• 2008

This paper proposes a method to establish an optical lifetime maintenance strategy for deteriorating bridges in consideration of life-cycle performance and cost. A program is developed based on the proposed method, which can generate optimum maintenance scenarios not only at the individual member level but also at the system level of the bridge. By applying the developed program is studied through the comparative analysis of maintenance strategies generated at each level. According to the results of comparison between maintenance strategies of the member-level analysis and system-level analysis. It is expected that the establishment of a maintenance strategy through the bridge system-level analysis considering target, members reflects practical and reasonable results.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.590-592
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• 2008

정부와 시설물유지관리 기관에서는 공공시설의 안전성 확보와 유지관리 업무의 생산성 향상을 위해 다양한 시설물유지관리시스템을 구축하여 운영중에 있으나 대응적 유지보수 체계의 한계로 인하여 합리적인 예산수립을 위한 최적의 의사결정을 하기가 어려운 실정이다. 이러한 이유로 유지관리의 효율성 증대 및 예산 절약을 위해 공공시설에 예방적 개념의 자산관리체계를 도입해야 한다는 요구가 증대되고 있다. 자산관리는 시설물의 최적화된 관리를 위한 경영전략으로 시설물 상태에 대한 공학적, 해석적 분석을 넘어 대상물을 자산으로 인식·평가하고 가치유지 및 향상을 목표로 하며 동시에 사용자의 최대만족을 얻기 위한 전략이다. 국내에서는 이러한 시대적인 요구에 따라 자산관리에 대한 연구가 진행 중이며 본 논문에서는 자산관리정보시스템을 개발하기 위한 해외 사례조사를 통해 시스템 핵심 기능을 도출하고 이를 통해 데이터 항목 분류방안을 제시하였다.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.67-77
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• 2009

Infrastructure asset management can be defined as the long term and cost effective management strategy to meet the required service level. In most developed countries, the major motivations of the introduction of asset management are increment in number of assets, extension of maintenance field, accounting approaches of public facilities, performance-based FM(Facility Management), limitations of public funds and public-private partnership, life cycle cost approach, and the development of information technology. This paper discusses the strategic and stepwise methods of introducing infrastructure asset management. Strategic approaches are suggested to develop the practical methods of condition and value assessment of assets, and long-term capital investment plan for optimized decision making(ODM). Required systematic processes are analyzed in terms of resource and technical limitations and detailed implementation plan for each development phases are suggested.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.1023-1032
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• 2006

In this paper, a new method for the bridge maintenance is proposed to overcome the limit of the existing methods and to implement the preventive bridge maintenance system. The proposed method can establish the lifetime optimum maintenance strategy of the deteriorating bridges considering the life-cycle performance as well as the life-cycle cost. The lifetime performance of the deteriorating bridges is evaluated by the safety index based on the structural reliability and the condition index detailing the condition state. The life-cycle cost is estimated by considering not only the direct maintenance cost but also the user and failure cost. The genetic algorithm is applied to generate a set of maintenance scenarios which is the multi-objective combinatorial optimization problem related to the life-cycle cost and performance. The study examined the proposed method by establishing a maintenance strategy for the existing bridge and its advantages. The result shows that the proposed method can be effectively applied to deciding the bridge maintenance strategy.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.677-686
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• 2006

In this paper, a more practical and realistic method is proposed to establish the lifetime optimum maintenance strategies of the deteriorating bridges considering the life-cycle performance as well as life-cycle cost. The genetic algorithm is applied to generate the set of maintenance scenarios that is the multi-objective combinatorial optimization problem related to lifetime performance and cost as separate objective functions, and the technique to select optimum tradeoff maintenance scenario is presented. Optimum maintenance scenarios could be generated not only at the individual member level but also at the system level of the bridge. Through the analytical results of applying the proposed methodology to the existing bridge, it is expected that the methodology will be effectively used to determine the optimum maintenance strategy for introducing a real preventive maintenance system and overcoming the limits of existing maintenance methods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.977-988
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• 2006

The goal of this study is to develop a realistic methodology for determination of the Life-Cycle Cost (LCC)-effective optimal seismic retrofit and maintenance strategy of deteriorating bridges. The proposed methodology is based on the concept of minimum LCC which is expressed as the sum of present value of seismic retrofit costs, expected maintenance costs, and expected economic losses with the constraints such as design requirements and acceptable risk of death. The proposed methodology is applied to the LCC-effective optimal seismic retrofit and maintenance strategy of a steel bridge considered as a example bridge in the accompanying study, and various conditions such as corrosion environments and Average Daily Traffic Volumes (ADTVs) are considered to investigate the effects on total expected LCC. In addition, to verify the validity of the developed methodology, the results are compared with the existing methodology. From the numerical investigation, it may be positively expected that the proposed methodology can be effectively utilized as a practical tool for the decision-making of LCC-effective optimal seismic retrofit and maintenance strategy of deteriorating bridges.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.879-890
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• 2017

The US Pavement Design method (AASHTO) and HDM-4, a road pavement maintenance decision system, are not suitable for domestic pavement design, construction and maintenance. KPRP(Korea Pavement Research Program) has been developed to reflect Korea's environmental conditions and vehicle characteristics, thereby, extending pavement life. The main objective of this study is to select the best alternative through Life Cycle Cost $CO_2$ (LCCC) calculations among three representative maintenance strategies using KPRP design software since the environment cost resulting from the extended pavement life will also differ. The analysis of this study illustrates that cumulative carbon emissions for 40 years in alternative 2 (Cutting and Overlaying at Year 30) is the lowest option among them, and the basic cost of $CO_2$ emission by various road maintenance and repair work can be used for suggesting an optimal maintenance strategy for highway agency.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.965-976
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• 2006

A realistic lifetime seismic-reliability based approach is unavoidable to perform Life-Cycle Cost (LCC)-effective optimum design, maintenance, and retrofitting of structures against seismic risk. So far, though a number of researchers have proposed the LCC-based seismic design and retrofitting methodologies, most researchers have only focused on the methodological point. Accordingly, in most works, they have not been quantitatively considered critical factors such as the effects of seismic retrofit, maintenance, and environmental stressors on lifetime seismic reliability assessment of deteriorating structures. Thus, in this study, a systemic lifetime seismic reliability analysis methodology is proposed and a program HPYER-DRAIN2DX-DS is developed to perform the desired lifetime seismic reliability analysis. To demonstrate the applicability of the program, it is applied to an example bridge with or without seismic retrofit and maintenance strategies. From the numerical investigation, it may be positively stated that HYPER-DRAIN2DX-DS can be utilized as a useful numerical tool for LCC-effective optimum seismic design, maintenance, and retrofitting of bridges.