• Journal of the Korea Institute of Building Construction
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• v.20 no.2
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• pp.183-190
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• 2020

Currently, the multi-unit houses are the largest in the ratio of housing types, and the number of households in multi-unit houses is steadily increasing. As the multi-family housing project continues, the accuracy of estimates for decision-making and feasibility assessment are required in the early stages of the project. Therefore, this study selected the influential factors affecting the estimated estimate and showed the relative importance of each factor through weight analysis and suggested the method of calculating the estimated estimate to improve the accuracy. The calculation plan presented through this study will be used as a useful data for project feasibility review and is expected to make a great contribution in preventing the economic loss of the client.

• Journal of the Korea Institute of Building Construction
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• v.20 no.2
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• pp.147-153
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• 2020

It is important to estimate the optimal construction cost at the early stage of the project. In this regard, conceptual cost estimate is an important factor for estimate optimal construction cost. However, domestic conceptual cost estimate are only used as cost per unit area according to the building type, and it's accuracy is not high. Hence, the purpose of this study is to calculate the approximate quantity and cost for reinforcing bars, concrete, and formwork by presenting a regression formula based on the total floor area of the common work items in the frame work. In order to verify the accuracy and validity of the regression formula presented in this study, a comparative analysis was performed by applying the regression formula and the traditional approximate quantity take-off method to real cases. As a result, the estimated error rate of the traditional method was -102~+55%, and exceeded the estimated conceptual cost estimate accuracy range of -50~+100% suggested by AACE(American Association of Cost Engineering). On the other hand, the error rate of the regression formula method presented in this study was -6.4~+11.62%. This can be used not only for conceptual cost estimate range of accuracy, but also for detailed estimates. However, it is necessary to analyze the factors that affect the unit price as well as quantity in order to calculate the appropriate cost.

• Korean Journal of Construction Engineering and Management
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• v.1 no.1 s.1
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• pp.63-71
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• 2000

The paper considers two non-deterministic methods of analysing the risk exposure in a cost estimate The fist method(referred to as the 'conventional statistical' method) analyses cost data directly, to describe a probability distribution for total cost. The second method(referred to as the 'Monte Carlo simulation' method) interprets cost data directly, to generate a probability distribution for total costs from the descriptions of elemental cost distribution. The common practice of allowing for risk through an all-embracing contingency sum or percentage addition is challenged. Rather than excluding conventional, non-deterministic methods, they are here presented as possibly the only of effective foundation on which to risk management in cost estimating.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.218-221
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• 2010

발주자는 건설 프로젝트의 주요 의사결정을 초기단계에 내리게 되므로 정확한 예산을 예측하는 것이 중요하다. 그러나 건설 프로젝트의 대형화, 복잡화 그리고 건설산업계의 새로운 패러다임인 BIM(Building Information Modeling)의 등장에도 불구하고, 초기단계에서 정확한 공사비를 예측할 수 있는 표준화된 산출방법이 없어 아직까지도 대부분의 설계사무소에서는 실시설계단계에서 확정된 설계안에 따른 견적을 이용하며 초과된 비용에 대해 통합품질을 저해하는 행위를 통해 조정하고 있다. 초기단계에서 보다 정확한 공사비를 예측하므로써 발주자는 의사결정을 함에 있어 올바른 판단을 내릴 수 있으며, 이 단계에서 발생한 정보를 활용하여 이후 단계에도 유용하게 쓰일 수 있을 것이다. 본 연구에서는 발주자 의사결정 지원시스템 상에서 BIM기반으로 개략공사비를 산출할 수 있는 프로세스를 제안한다.

• Korean Journal of Construction Engineering and Management
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• v.8 no.4
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• pp.110-118
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• 2007

For deciding the owner's budget of the building construction in the predesign stage, the probabilistic methodologies for estimating the cost are often studied, however these parameter-based conceptual estimating methodology has limitation of applying it to the practical business because it hardly can link the design decision-making and the cost estimating and control. Besides if the result of detail estimating after detail design is over the budget, locally and arbitrarily control the level of interior design and fix the design. This research proposed the prototype-based cost estimating model for building interior construction which leads to estimate the interior cost easily linking with design decision-making and supports to evaluate the design alternatives in the schematic design and the design development stage for office buildings. The model divides the building on the design process by Element Breakdown Structure and presents the design alternative by selecting the elements of each room from the database accumulated the historical office buildings' prototypes and estimates the cost. The 2 case studies presented to validate the effectiveness of as the linking tool integrating the design and construction data and applicability to the practical design on the presented prototype-based model.

• Korean Journal of Construction Engineering and Management
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• v.15 no.2
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• pp.53-61
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• 2014

Previous studies reveal the need for a tool to cost estimation of building design in early design stages. This paper proposes an internal finishes cost model tool to address this need. The tool allows users to evaluate the functionality, economics and quality of finishes concurrently with high-rise building design. Lack of information in the early stages of the project enables a relatively accurate estimates of work to raise up. Measurements are automatically extracted from simple design information and profile driven estimates are revised in real-time. The data model uses a flexible unit rate system that can easily be extended to other estimate dimensions such as mix-use building surcharge rate estimation. The approach illustrated in this paper is applicable to BIM tool conceptual estimation that support for massing purposes other than the one chosen for this study.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.212-215
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• 2008

When managers predict exact construction cost at early stage and design phase, they can reduce construction cost in a more efficient way than to predict at construction stage. But present of public construction cost estimation and management almost after the construction documents design phase. Therefore, construction cost management in the early stage and schematic design phase to generally use approximate estimating is not correct. Accordingly, this study analyze problem of current cost estimating method and a concrete cost plans make using case information of actual cost to analyze in schematic design phase. Possible to check going on the suitable design, this study conducts the preliminary research for the development of cost estimating model.

• Korean Journal of Construction Engineering and Management
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• v.15 no.1
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• pp.3-10
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• 2014

High-rise buildings need thorough cost management because of large size and high risk. Cost management makes a budget by establishing and analyzing detail element at planning phase, needs cost control as each design phase, then reflected to next design. This research develops a schematic estimation model based on vertical and horizontal elements at design phase for structure cost of high-rise buildings to reduce error range and use data as design management. Usability of the model is confirmed by case study. The estimation model is expected to contribute to making the cost model more effective and satisfactory to concerned in construction or budget department and manage keeping track of the cost.

• Korean Journal of Construction Engineering and Management
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• v.15 no.4
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• pp.95-106
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• 2014

The outer surfaces of free form buildings contain panels with two-directional curvatures. To construct these panels, complex geometric surfaces should be divided into forms and sizes that can be manufactured and constructed efficiently. Because the bigger the curvatures of these panel, the more expensive the construction costs, these complex curvatures should go through optimal process of reinterpretation to minimize the curved surfaces with complex two-directional curvatures, which is called panel optimization. Small construction and design companies have trouble in calculating even rough estimate and cannot adjust expected construction cost of the panels based on comparison of design alternatives in conjunction with panel optimization process due to lack of knowledge and experience. This study conducts the research that can support designers' cost decision-making in the design stage of the free form buildings with respect to the panel optimization process. A 3D commercial application specialized to modeling free form shapes is used for the purpose.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.2
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• pp.125-134
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• 2015

Spherical type LNG carrier has many advantages, but has a demerit it is more expensive than membrane type one. Therefore, when calculating the initial estimate of spherical type LNG carrier, high accuracy calculation of tank weight has to be carried out. In this study the simplified analysis method which is able to calculate stresses of all the tank zones is established and has special feature to deal with static and dynamic loading. In order to verify the established method, the design results obtained through the method in this study have been compared with those of existing ship obtained from finite element analysis. As a result, the usability of simplified analysis method has been confirmed.