• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.315-316
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• 2021

The proportion of maintenance work has been increasing due to the recent aging of the infrastructure, but the standardized construction cost estimation standards are insufficient for this. In particular, reinforced concrete structures are being applied to many structures such as buildings and bridges, and various construction methods for maintenance of reinforced concrete structures are being developed and applied. In this study, we surveyed about the current status of the construction method for the maintenance work of reinforced concrete structures and analyze the factors of the revision of the construction cost estimate standard for the reinforced concrete structure maintenance.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.232-237
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• 2008

Several research institutes including KISTEC and KRRI etc., recently, have studied maintenance activities and performance, in order to determine proper maintenance level and maintenance cost of rail tracks. But it may extremely difficult to make a decision in maintenance matters of concrete track and ballast containing other sub-components. For these reasons, this study investigate variables related to current maintenance, essential maintenance, and preventive maintenance. It is intended to suggest estimation method of proper maintenance cost maximizing rail track performance. It is stated that proposed approach may be very useful to make a decision of proper maintenance level. Typical section of rail track is applied for calculation of life cycle cost according to each maintenance strategy. A proper profile for maintenance is determined minimum life cycle

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.390-399
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• 2011

Generally the life-cycle cost of complex systems composed of several sub systems or equipments such as train, aircraft weapon systems is spent much more during operation and maintenance phase than development phase. The maintenance cost for maintaining the availability and extending the life span of systems comprise a large proportion of systems operation cost. The cycle of preventive maintenance affects operation and maintenance cost a lot. In this study we introduce a way minimizing life-cycle cost of systems by calculating more reliable preventive maintenance period than the results of previous study using systems reliability data considered the reliability and failure effect ratio of sub-systems or components. We can solve the preventive maintenance period problem known as NP-Hard as quick as possible by using modified genetic algorithm than using other models introduced in previous study.

• Journal of Electrical Engineering and Technology
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• v.7 no.6
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• pp.814-823
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• 2012

Electric power transmission utilities make an effort to maximize profit by reducing their electricity supply and operation costs while maintaining their reliability. The development of maintenance strategies for aged components is one of the more effective ways to achieve this goal. The reliability centered approach is a key method in providing optimal maintenance strategies. It considers the tradeoffs between the upfront maintenance costs and the potential costs incurred by reliability losses. This paper discusses the application of the Particle Swarm Optimization (PSO) technique used to find the optimal maintenance strategy for a transmission component in order to achieve the minimum total expected cost composed of Generation Cost (GC), Maintenance Cost (MC), Repair Cost (RC) and Outage Cost (OC). Three components of a transmission system are considered: overhead lines, underground cables and insulators are considered. In regards to aged and aging component, a component state model that uses a modified Markov chain is proposed. A simulation has been performed on an IEEE 9-bus system. The results from this simulation are quite encouraging, and then the proposed approach will be useful in practical maintenance scheduling.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1481-1486
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• 2008

To apply more effective the RCM analysis for railway vehicle, the maintenance cost per equipment should be considered together with failure criticality per equipment considered in existing. This paper is described the systematic calculation of maintenance cost considering the RCM analysis of railway vehicle. To calculate the maintenance cost systematically, the cost breakdown structure was established, and basic cost information and calculated cost items were defined. In addition, the linking between calculated cost and RCM analysis was considered. In future, this proposal would be used to analysis of cost effectiveness through RCM analysis of railway vehicle.

• Korean Journal of Construction Engineering and Management
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• v.6 no.6 s.28
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• pp.171-180
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• 2005

Public rental housing is constructed, owned, and managed by the public sector. The public institution for the public rental housing controls the whole building life cycle from the construction to the demolition. The construction company for the house built for sale is strongly interested in the cost for the initial investment, while the public institution is more focused on the maintenance cost for the preservation of the buildings Nevertheless, the maintenance cost of the public rental housing has been only managed as the accounting factor without the systemic research and analysis on the actual condition. This paper shows how expenses are related to the degree of obsolescence and presents the differences of the maintenance costs by the housing area and expenditure trends (vs time) of the maintenance costs, through analyzing time series data of public rental housing maintenance cost. Further, this paper helps understanding the causes of the differences of the maintenance costs by housing areas and characteristics of the expenditure trends. After all, this paper contributes to the improvement of the reliability and the practicality for the Life Cycle Cost modeling and the maintenance cost estimating.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.22-26
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• 2011

The urban transit vehicles has very complicated structures composed electric and mechanical parts and systems. Its system is important to insure operating stability pursuant to massive transfer. Also, its system takes a lot of maintenance cost than constructing cost due to its system which has longtime life cycle. Generally it is know that maintenance cost affect a lot on total cost because its life cycle cost takes a part more than 60~70%. For these reason, it is really important to reduce its maintenance cost through efficiently operation and maintenance management system construction.

• Journal of Applied Reliability
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• v.6 no.3
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• pp.195-203
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• 2006

This paper deals with cost analysis model in periodic maintenance policy. The repair policy with minimal repair is considered as follow : as the occurrence of failure between minimal repair and periodic interval time, unit is replaced by a new unit before the periodic maintenance time comes. Then total expected cost per unit time is calculated according to time delta t in a view of customer's. The total expected costs are included repair and usage cost : operating, fixed, minimal repair, periodic maintenance and new unit expected cost. Numerical example is shown in which failure time of item has Normal distribution.

• Journal of Applied Reliability
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• v.6 no.2
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• pp.151-161
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• 2006

This article is concerned with cost analysis model in periodic maintenance policy. The repair policy is differently applied according as unit importance during an item being used and unit restoration during an item being failed. So in this paper the repair policy with minimal repair is considered as follow : as the occurrence of failure between minimal repair and periodic interval time, unit is replaced by a spare unit until the periodic maintenance time arrived. Then total expected cost per unit time is calculated according to scale parameter of failure distribution in a view of customer's. The total expected costs are included repair and usage cost : operating, fixed, minimal repair, periodic maintenance and spare unit cost. Numerical example is shown in which failure time of item has Erlang distribution.

• 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.