• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.12-13
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• 2013

Free-form building is increasing because of request that an order to raise the value and request of the local residents and the government trying to own iconic and beautiful buildings. In addition, the installation and production of free-form concrete segment are now available because of development of construction technology, such as the development of materials and equipment. However, the production of free-form concrete segment requires a lot of time and manpower than shaping. In particular, resources of the mold for the production of free-from segment will be invested excessively because mold can not be recycled. Thus, the problems of increased costs, construction periods and loss of productivity occur. To solve these problems, this study proposes a technique of making the mold of for variable within a short time. Technique proposed in this study can be recycled die and will realize fast and accurate free-form concrete segment.

• Journal of Ocean Engineering and Technology
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• v.17 no.6
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• pp.16-22
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• 2003

In this paper, the method of determining the economically-optimal design section of rubble mound breakwater, using ADS program, was studied to supplement the deterministic approach. First of all, the design waves are computed, according to the return periods, using the Weibull distribution from the data of waves at the location of the breakwater. In order to take an optimal section, according to the return periods, the ADS program was used. The restriction conditions and objective functions are decided from the references of the specifications and standard manuals for Coastal and Harbor Construction Work. Results from this study support the ADS program as an appropriate method for determining the economically-optimal section of rubble mound breakwater, comparing the construction costs and the initial and damage repair costs for its life time.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.73-74
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• 2020

Predicting the compressive strength of concrete is important for shortening construction time and reducing construction costs. In this study, the coefficients required for maturity method and compressive strength prediction equation were calculated by measuring the cement hydration reaction rate, concrete setting time and ultimate strength. The experiment was conducted in an isothermal environment of 10℃, 20℃ and 30℃ using a normal Portland cement, and the experiment was conducted with a total of 9 levels of W/C (40%, 50%, 60%) of 3 levels for each temperature. As a result of comparing the predicted strength and the measured strength for each blend, only an error of less than 5% was found for all blending and curing periods.

• Journal of Korea Port Economic Association
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• v.24 no.3
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• pp.23-35
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• 2008

The purpose of this paper is to suggest a rational cost allocation method that is efficient and fair. Cost allocation by taking cooperative game theory shows fair allocation considering marginal cost by ship type. Current berth occupancy charging method can not recover quay construction costs. Because it levies charges according to berthing time and tonnage of ships without considering the recovery of quay construction costs. And there are also cross subsidies among ships. This paper suggests the cost allocation method of cooperative game theory as a fair and efficient method.

• 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 Korean Society of Safety
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• v.30 no.5
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• pp.29-36
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• 2015

Common utility tunnel is essential to the daily lives of people underground utilities (electricity, gas and supply facilities such as water, communication facilities, sewer facilities, etc.) to improve the appearance by co-acceptance and disaster prevention, important for the conservation of the city's population was concentrated road construction the city-based facilities. There is recognition of the importance of the various supply treatment facilities in common utility tunnel as infrastructure to accommodate joint according to the city expanded, the demand for infrastructure. In this paper, a cost-benefit analysis using a one-time occurrence, without simply relying on cost or current cost, project manager for the city-dimensional feasibility study conducted, the user level of the maintenance costs and user costs, including social costs items from various angles can be investigated and proposed a mechanism of economic feasibility common utility tunnel. Evaluation of the proposed technique is cost-benefit and cost caused by installing common utility tunnel the existing pipeline area - was investigated by the benefit analysis, extended and repeated common utility tunnel installation depends much affected by the excavation, so users of reducing the number of repeat excavation convenience can be seen that this occurs.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.130-135
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• 2001

In this study, I have researched into the causes of defects in apartment house, The results of this study are listed below. (1) Water leakages which result from land sinking and cracks, results of misuse of back filling method, are the main reason of defects in civil engineering work and architectural work. (2) Inexperience and unwillingness are the main reason of defects in plaster work. (3) In windows work and painting work, the main reasons are lacks of precision construction and efflorescence resulting from outdoor air, respectively. (4) Defects in waterproofing work and electric work result from fault construction by low unit Costs. (5) Equipment work requires uses of standardized construction materials and management, and landscape architecture work requires minimizing human mistakes, for instance, degin carelessness. For the reasons stated above, the causes of defects in apartment house are insufficient construction labors, inferior construction materials, urgent construction process time, and conscientiousless industrialists who only seek after a profit margin.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.277-278
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• 2021

Conflict in public construction projects has increased for the last decades. It not only entails enormous social and economic costs but also makes stakeholders suffer from unnecessary expense and time waste. This study defines the the conflict index for public construction projects based on news data, and calculates conflict index for representative past and current public construction projects that has been deepened conflicts at the national level. The result indicates that the major conflict issue of the 2nd Jeju Airport Project are the environment and location whereas that of the Gaduk New Airport Project are the safety, location and necessity. This approach is expected to enable construction project managers to manage conflicts quantitatively based on comparing with past cases.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.728-731
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• 2007

In-planned duration and cost at project closing are the two of criteria of successful project and successful project management. In Vietnam, regularly, construction projects are delayed and their costs are overrun. This research employed a questionnaire survey to elicit the causes of this situation by interviewing 87 Vietnamese construction experts. After processing data, 21 causes of delay and cost overruns appropriate with building and industrial project in construction stage were inferred and ranked. Spearman's rank correlation tests showed that there're no differences in the viewpoints between parties in project.

• Journal of the Korea Institute of Building Construction
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• v.4 no.4
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• pp.117-126
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• 2004

Construction industry is faced with the problems such as the quickly changeable circumstance and increasing construction companies due to regulation mollification of company registration. In order to overcome these problems, new estimation system based on historical estimation cost is ready to introduce by government step by step. But the time of transition for estimation system causes another problems such as chaos addition to simultaneity of a standard of estimation system and new estimation system, lack of related regulation, accumulation of historical extensive cost data, and adjustment methodology when historical estimation data is applied to next projects. The purpose of this study is to suggest the change factors by activities for estimating historical cost for apartment housing projects. New estimation system is based on historical construction data. For application of this system, the standard adjustment methodology system is necessary. and extensive cost data should be accumulated under an unified construction work classification system. Therefore in this study, according to the construction work classification system, every apartment housing project was classified to 16 work classifications, and 7 major composed items which occupy more than 85% of construction costs are analyzed by detailed activities and by average ratio and maximum ratio each of them. In the result of the study, furniture work, foundation work and masonry work are the works which have big gap of costs between average ration and maximum ratio. In addition to suggestion of change factor by work species, 5 qualified construction specialists are interviewed and change factors in 7 major works are analyzed.