• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.387-390
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• 2008

The importance of the life cycle cost analysis for construction projects of bridge has been recognized over the last decades. Accordingly, theoretical models, guidelines, and supporting softwares have been developed for the life cycle cost analysis of bridges. However, it is difficult to predict life cycle cost considering uncertainties precisely. This paper presents methodology for optimal design of substructure for a steel box bridge. Total life cycle cost for the service life is calculated as sum of initial cost, damage cost considering uncertainty, maintenance cost, repair and rehabilitation cost. The optimization method is applied to design of a bridge substructure with minimal cost, in which the objective function is set to life cycle cost and constraints are formulated on the basis of Korean Bridge Design Specification. Initial cost is calculated based on standard costs of the Korea Construction Price Index and damage cost on the damage probabilities to consider the uncertainty of load and resistance. An advanced first-order second moment method is used as a practical tool for reliability analysis using damage probability. Maintenance cost and cycle is determined by a stochastic method and user cost includes traffic operation costs and time delay costs.

• Journal of the Korea Institute of Building Construction
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• v.2 no.1
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• pp.155-162
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• 2002

In this research, I finally came to a conclusion analyzing the connection among managing of each items in management expenses, the size of each complex and stories, and the term of using. (1) In the managing cost regarding to the management manner, although the managing cost of self-governing management is less imposed than the one of commission management, there is slight difference between those Costs. And it is more important to consider the effectiveness of management than to emphasize reduction of management cost. (2) The higher the stories, the higher the managing cost of elevator per the unit area. It Is caused by the fact that the father the distance of the elevator operating, the higher the electric charges. (3) The third of one of total management cost goes to pay the personnel expenses. So I found that the effective management of the expenses is available to reduce management cost. (4) The higher the stones, the lower the cost of personnel expenses including the cleaner cost. (5) The sum of costs assigned in repairment and management increases in proportion to the term of using. The costs assigned in special repairment and management are interacting to each other. (6) To reduce the management cost, we have to cut down the personnel in security guard that occupies one third of total management cost with application to the joint security system and operation of the self-governing guard. Through this process, it will be easy to accomplish the rationalization of contract with an outside order. Because the improvement of management service is not only the responsibility of owner but also the one of dwellers. And it Is imperative to realize the importance of cooperation and trust between the owner and dwellers. And the establishment of effective managing system which has convenience and rationality must be settled without delay.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.147-149
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• 2015

A nuclear power plant construction project normally involves a large construction work of which the total project cost is over 5 trillion Won, Such a large-scale construction project has the risks of schedule delay and quality degradation due to increase in project cost, because designs are changed due to design errors. The reasons for design changes during installation are 1) insufficient engineering capability of the owner, 2) information discontinuance due to the multiple package method, and 3) inefficient constructability review processes. Accordingly, this study proposes, through problem analysis, a method of developing a constructability review system that utilizes constructability review processes and a data-based technology (3D modeling) that are optimized for nuclear power plant construction projects. It also presents a method of establishing a system for reviewing constructability in which constructability review processes and a Database (3D model, Schedule, Design change Items) are linked each other.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.46-51
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• 2003

The government's financial subsidy system for the construction project of urban rail transit needs to be revised. In 1998, the central government raised its subsidy rate to 50$\%$ of the total cost of construction. The 'method for differentiating subsidies depending on construction type and transit System' is suggested here, so that a subsidy rate can be raised for the construction of Light Rail Transit, which costs less to construct. Such methods will force local governments to make decisions regarding construction method and project size in a more rational manner.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.261-266
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• 2007

In this research, we studied an estimating method in client's sight to estimate the total construction cost which is based on the historical cost data at the early stage of the office buildings as a public phase. It is very difficult to analyze the estimation accurately and logically. When a client estimates a project, he/she has to consider there are many issues at the planning step, according as office buildings become gradually diversified as well as their roles continuously extended. Therefore, those are usually make problems for wasting the budget in accordance with the cost estimation errors. Moreover, many kinds of public construction projects, especially such as school, office, sports complex, and the others, have been invested the private finances defined as BTL(Build Transfer Lease) method that are required to manage the detailed process more strictly from initial planning. In order to make an effective planning, the long-term users amount and the building life cycle at the beginning of project should be considered previously and then it may enable to achieve an appropriate project plan. But actually considering overall variables in a building planning is impossible. Accordingly, suggesting a regression model based on the historical cost data from many similar types of office building to support client's role known as estimating the total cost at the early stage. And then performing the test against the proposed model to research the reasonability as using the historical cost data of Japan office buildings.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.277-278
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• 2023

The need for maintenance of bridge infrastructure is increasing due to aging, and the cost of maintaining the infrastructure must be calculated for effective budget distribution. Therefore, in this study, representative defects according to bridge superstructure type are derived to calculate the cost for each repair method. First of all, the representative bridges, PSCI girder bridge, Rahmen bridge, Steel box girder bridge, and RC slab bridge, were selected as superstructures using BMS data, and repair methods for defects were presented. In addition, the cost of the repair method by superstructure type was compared. This result is expected to predict total maintenance costs in consideration of the maintenance cycle.

• Journal of KIBIM
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• v.7 no.3
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• pp.40-48
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• 2017

It only takes one failed project to wipe out an entire year's profit, when the projects are not managed efficiently. Additionally, escalating costs of materials and a competitive local construction market make subcontractors a challenge. Subcontractors have finite resources that should be allocated simultaneously across many projects in a dynamic manner. Significant scheduling problems are posed by concurrent multi-projects with limited resources. The objective of this thesis is to identify the effect of productivity changes on the total cost resulting from shifting crews across projects using a descriptive model. To effectively achieve the objective, this study has developed a descriptive cost model for a subcontractor with multi-resources and multi-projects. The model was designed for a subcontractor to use as a decision-making tool for resources allocation and scheduling. The model identified several factors affecting productivity. Moreover, when the model was tested using hypothetical data, it produced some effective combinations of resource allocation with associated total costs. Furthermore, a subcontractor minimizes total costs by balancing overtime costs, tardiness penalties, and incentive bonus, while satisfying available processing time constraints.

• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.135-144
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• 2009

The primary focus of this study has been directed towards assessing the potential impact of construction method improvement on a reduction in project cost. A total of 90 actual application cases were collected from a public organization and private construction firms, and 32 cases were used in analysis by adopting a synthetic approach. The level of cost reduction was measured in terms of material and labor cost by comparing the existing method and the improved method. An analysis of the results indicates that project cost can be reduced by up to 5.26 percent compared to a normal project by adopting a synthetic approach. Additional benefits include the assurance of uniform quality, savings in terms of labor and/or materials, and improved productivity. The potential of the applicability of this approach to other types of buildings and the implications of research findings were discussed in detail.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.151-158
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• 1998

This paper presents an optimal decision model for minimizing the life-cycle cost of steel box girder bridges. The point is that it takes into account service life process as a whole, and the life-cycle costs include initial (design, testing, and construction) costs, maintenance costs and expected failure costs. The problem is formulated as that of minimization of expected total life-cycle cost with respect to the design variables. The optimal solution identifies those values of the decision variables that result in minimum expected total cost. The performance constraints in the form of flexural failure and shear failure are those specified in the design code. Based on extensive numerical investigations, it may be positively stated that the optimum design of steel box girder bridges based on life-cycle cost approach proposed in this study provides a lot more rational and economical design, and thus the proposed approach will propose the development of new concepts and design methodologies that may have important implications in the next generation performance-based design codes and standards.

• Korean Journal of Construction Engineering and Management
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• v.6 no.2 s.24
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• pp.111-119
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• 2005

Although the life-spans of most apartment buildings are over fifty years, they are often demolished and retrofitted only after twenty years, in spite of its remaining life expectancy, resulting in economical waste. The purpose of this paper is to estimate optimum remodeling period of apartment buildings using total cost. In this study it is seen that total sum of running cost of life-span on the buildings is about 4.69 times of initial cost till the fifty years of the life expectancy. The optimum remodeling period of the apartment building is thirty years applying the discount rate of $4.17\%$ and the discount rate should be $6.122\%$ to obtain the forty years of the optimum remodeling period. From the sensitivity analysis based on the change of the discount rates, it is seen that if discount rate decreases the optimum remodeling period can be extended, or vice versa. As a result, a time of the demolished and remodeling can be expected and the basic data can also be established for lengthening life-span of the apartment buildings.