• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2010.04a
• /
• pp.162-165
• /
• 2010

합리적인 교량 대안선정을 위해서는 설계 시 경제성, 경관성, 안전성 및 기능성, 유지관리 용이성, 시공성 등 다양한 속성을 고려하여야 한다. 이 중 경제성은 초기비용뿐만 아니라 공용수명에 걸쳐 발생하는 유지관리비용, 보수 보강비용, 해체 폐기비용 등의 합인 총 생애주기비용에 대해 최소의 비용으로 최상의 가치를 창출하도록 하여야 한다. 본 연구에서는 건설계획과정에서 대표적으로 고려될 수 있는 대안으로 세 가지 교량 형식(강상자형교, 소수주형교, PSC-I형 거더교)을 대상구조물로 선정하고 교량의 공용수명은 상태등급곡선으로부터 추정한 내하율 곡선을 사용하여 산정하였다. LCC최적설계를 위해 설계변수, 제약조건, 목적함수를 구성하였고, 총 생애주기비용을 공용수명으로 나눈 연간생애주기비용을 사용하여 하여 합리적인 교량의 경제성 분석을 수행하였다.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.5
• /
• pp.2081-2091
• /
• 2013

Recently, the demand on the practical application of life-cycle cost effectiveness for design and rehabilitation of civil infrastructure is rapidly growing unprecedently in civil engineering practice. Accordingly, in the 21st century, it is almost obvious that life-cycle cost together with value engineering will become a new paradigm for all engineering decision problems in practice. However, in spite of impressive progress in the researches on the LCC, the most researches have only focused on the Deterministic or Probabilistic LCC analysis approach and general bridge at design stage. Thus, the goal of this study is to develop a practical and realistic methodology for the Life-Cycle Cost LCC-effective optimum decision-making based on reliability analysis of bridges at design stage. The proposed updated methodology is based on the concept of Life Cycle Performance(LCP) which is expressed as the sum of present value of expected direct/indirect maintenance costs with expected optimal maintenance scenario. The updated LCC methodology proposed in this study is applied to the optimum design problem of an actual highway bridge with Cable Stayed Bridges. In conclusion, based on the application of the proposed methods to an actual example bridge, it is demonstrated that a updated methodology for performance-based LCC analysis proposed in this thesis, shown applicably in practice as a efficient, practical, process LCC analysis method at design stage.

• Journal of the Korean Society for Railway
• /
• v.11 no.1
• /
• pp.107-113
• /
• 2008

As it recently appears that LCC (Life Cycle Cost) analysis may be considered as an essential method for economic evaluation of infrastructures. Many researches have been made to assess LCC of each facility based on reasonable methods. However, expected maintenance repair cost must be reasonably estimated to enhance the reliability of LCC analysis through systematic and rational methods. This study is intended to propose a rational approach to reliability-based LCC analysis of high-speed railway steel bridges considering lifetime corrosion and fatigue damage. However in Korea, since high speed railway steel bridges are only recently constructed, no direct statistical data are available for the account of the maintenance cost and thus their maintenance characteristics are not clear yet. In this paper, for the assessment of expected maintenance/repair cost, the fatigue system reliability analysis incorporating the corrosion effect is proposed by considering the corrosion and fatigue damage using measured data of high speed railway steel bridges. A model proposed by Rahgozar, of at for fatigue notch factor considering the corrosion effect is used in order to incorporate the corrosion effect into the fatigue strength reduction and S-N curve. Finally, the effectiveness of LCC model proposed for high-speed railway steel bridges is demonstrated by a numerical example.

• Journal of the Korean Society of Safety
• /
• v.25 no.6
• /
• pp.115-122
• /
• 2010

The importance of the life cycle cost (LCC) analysis for bridges has been recognized over the last decade. However, it is difficult to predict LCC precisely since the costs occurring throughout the service life of the bridge depend on various parameters such as design, construction, maintenance, and environmental conditions. This paper presents a methodology for the optimal life cycle cost design of a bridge. Total LCC for the service life is calculated as the sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The optimization method is applied to design of a bridge structure with minimal cost, in which the objective function is set to LCC and constraints are formulated on the basis of Korean Bridge Design Code. Initial cost is calculated based on standard costs of the Korea Construction Price Index and damage cost on damage probabilities to consider the uncertainty of load and resistance. Repair and rehabilitation cost is determined using load carrying capacity curves and user cost includes traffic operation costs and time delay costs. The optimal life cycle cost design of a bridge is performed and the effects of parameters are investigated.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.4
• /
• pp.19-25
• /
• 2016

Engineering structures including civil infrastructures require a life-cycle cost and benefit during their service lives. The service life of a structure can be extended through appropriate inspection and maintenance actions. In general, this service life extension requires more life-cycle cost and cumulative benefit. For this reason, structure managers need to make a rational decision regarding the service life management considering both the cost and benefit simultaneously. In this paper, the probabilistic decision tool to determine the optimal service life based on cost-benefit analysis is presented. This decision tool requires an estimation of the time-dependent effective cost-benefit under uncertainty to formulate the optimization problem. The effective cost-benefit is expressed by the difference between the cumulative benefit and life-cycle cost of a deteriorating structure over time. The objective of the optimization problem is maximizing the effective cost-benefit, and the associated solutions are the optimal service life and maintenance interventions. The decision tool presented in this paper can be applied to any deteriorating engineering structure.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.4
• /
• pp.101-111
• /
• 2013

In this study, DEA (Data Envelopment Analysis) was carried out on the four bridges, which have the same extension (L=1,615m), in order to select the most superior, economical method of construction using the LCC concept of each bridge structure in the case of the Ulsan-Pohang double track railway which is scheduled to be constructed. DEA models were analyzed with the CCR model, which was designed for the evaluation of relative efficiency of each model. The initial construction costs, maintenance costs, indirect costs (user costs + indirect loss of social costs), and life cycle costs were used as input variables, and average duration was applied as the output variable. LCC was applied to calculate the input variables, and to get the costs of LCC, 100 years of period and 4.83% of real discount rate were applied, and the costs are classified into initial construction, maintenance, user, and indirect loss of social cost. The analysis results showed that the Method 2 and 3 were evaluated as the most efficient, and the other alternatives were evaluated as the following order; Method 1, the default, and Method 4.

• Korean Journal of Construction Engineering and Management
• /
• v.13 no.6
• /
• pp.71-83
• /
• 2012

The use of technical proposal tendering has been expanding recently with the aim of effecting cost reduction, quality enhancement, technological development and value realization centered on multifunctional administrative cities, innovation cities, and the Yongsan relocation project. In line with the increasing interest towards life cycle cost improvement measures as an important evaluation category concerning technical proposal tendering, efforts in preparing measures that can execute the security of credibility and objective evaluation concerning architectural life cycle cost are being made. However, problems such as lack of applicable cases of design development and detail design, distortion of initial construction costs concerning the original plan, combination of constant price and current price, the ambiguity of the calculation standards between tendering corporations, inaccuracy of terms, and insufficient compositional formats concerning life cycle improvement measures are being cited. Accordingly, this study sought to propose a measure to improve the compositional guidelines, format, and standards so that a systematic life cycle cost evaluation can be executed for the reliable distinction of each participating corporation, enhanced credibility and objective evaluation of the life cycle cost improvement measure for technical proposals.

• Korean Journal of Construction Engineering and Management
• /
• v.23 no.3
• /
• pp.66-73
• /
• 2022

In order to induce users to purchase excellent products in the water industry that satisfy the technical standards of excellent products, in this study, it is to present the advantages of the cost aspect of the pumps as the objective basis. It will be to promote technology development of domestic water companies and to create a virtuous cycle structure in the water industry. In order to present an objective basis for the merits in terms of cost, an economic evaluation was conducted through life cycle cost analysis. For the LCC analysis, initial cost (pump cost and installation cost), operation cost (energy cost and maintenance cost) and demolition cost (disposal cost and residual value) are searched and calculated. As the results of comparison on two capacity of pumps, the energy cost of the excellent pump is 212 million KRW lower than the that of general pump in the large pump. The cost of excellent pump was 17 million KRW lower than that of general pump in small capacity pump. As the results of sensibility test, if the product is developed in the direction of improving pump efficiency and increasing the replacement cycle of consumables, it is predicted that the effect on LCC will be large.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.6
• /
• pp.131-142
• /
• 2007

The road user cost in indirect costs as well as direct costs such as the inspection/ diagnosis cost and the repair/reinforcement cost should be considered as one of the important items in the life-cycle cost-effective design and maintenance of the bridges. To estimate the road user cost, this paper formulates the road user cost as a sum of the user delay cost and the vehicle operating cost considering the detour effect. A numerical traffic simulation and a regression analysis are performed to develop a regression model due to a time delay. The proposed regression model is applied to the generation of the maintenance strategy based on the life-cycle cost and performance, and its effectiveness and applicability is investigated. The road user cost has a great influence on establishing the maintenance strategy, and the proposed regression model could be successfully utilized to estimate the road user cost of a bridge.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.15 no.4
• /
• pp.557-566
• /
• 2002

This paper presents an optimum deck and girder system design for minimizing the life-cycle cost(LCC) of steel box girder bridges. The problem of optimum LCC design of steel box girder bridges is formulated as that of minimization of the expected total LCC that consists of initial cost, maintenance cost and expected retrofit costs for strength, deflection and crack. To demonstrate the cost effectiveness of LCC design of steel box girder bridges, the LCC optimum design is compared with conventional design method for steel box girder bridges. From the numerical investigations, it may be positively stated that the optimum design of steel box girder bridges based on LCC will lead to mote rational, economical and safer design.