• 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.

• Journal of the Korea Institute of Building Construction
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• v.14 no.5
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• pp.415-422
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• 2014

There is growing difference between a planned value and an actual cost for increasing as an risk of construction cost. A construction cost index is an alternative to redeem a problem, but it is still very difficult to reduce an actual differential as a price fluctuation. Furthermore an existing theory of a construction cost index is overly complex, and is unsuitable for using in working-level. This study suggests an optimum correction rate in respect of a total construction cost. It is analyzing the actual cost of 53 public buildings that the Public Procurement Service ordered. The objects are main processes that include architectural works, mechanical works, electrical works, telecommunication works, and service facilities. It is compared a total construction cost based on absolute error rate using the median from frequentist principle. For this, it is selected the suitable regression model and set a correction rate.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.43-52
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• 2018

Generally, research on construction cost has been done mostly regarding its direct cost, thus model regarding indirect cost lacks attention. This research seeks to introduce a model to predict on-site overhead cost for apartment construction projects, which constitutes a big portion in Korean construction industry. We devised an equation of 9th degree via curve-fitting, using multiple on-site actual expense data, which can be used to calculate per-progress rate, per-day on-site overhead cost. We further show prospective usage of the model by applying it on construction projects sizing about 30 billion won. Regarding the fact that previous studies could not recognize pattern changes of a total on-site overhead cost, this model is worthy of its conveniency and thoroughness, as well as providing reasonal ground for its derivation in predicting on-site overhead cost of apartment construction projects.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.120-125
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• 2003

The estimated construction costs derived at the Planning stage of a project are utilized as important data determining the feasibility of overall project. Therefore the clients usually expect to have estimations of the construction cost as precise as possible and there has been extensive studies carried out by the cost specialists worldwide to satisfy this client's specific need whereas the local estimators still heavily rely on producing quantities and detail quotations only. This paper is to introduce a case study where elemental/functional area cost analysis is incorporated into a database system for the improved accuracy in cost estimations.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.149-152
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• 2007

최근 모든 분야에 대한 전산화가 가속화됨에 따라 업무 처리 능력의 향상과 함께 시간 비용의 절감을 이루고 있다. 이러한 추세와 함께 건설 분야에서의 전산화가 진행 중이다. 본 논문에서는 굴착장비의 전류 값과 굴착 깊이 계측을 통해 깊이에 따른 지반 강도를 전산화 시켜 추정함으로써 보다 합리적으로 말뚝 기초를 시공하는 방법 개발하고자 한다. 본 시스템은 건축, 토목, 건설 분야에서 국내 최초로 시도되는 것으로, 실제 공사 현장에서 획득되는 데이터의 분석을 도와 측정 오류(Human Error)를 최소화함은 물론 공사비 절감, 신속한 공사 정보 제공 등의 파급효과를 기대할 수 있다.

• Korean Journal of Construction Engineering and Management
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• v.21 no.1
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• pp.50-60
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• 2020

Estimates of project costs in the early stages of a construction project have a significant impact on the operator's decision-making in important matters, such as the site's decision or the construction period. However, it is difficult to carry out the initial stage with confidence because information such as design books and specifications is not available. In previous studies, case-based reasoning was used to predict initial construction costs, and genetic algorithms were used to calculate the weight of the inquiry phase among them. However, some say that it is difficult to perform better than the current year because existing genetic algorithms are calculated in random numbers. To overcome these limitations, correlation numbers using correlation analysis rather than random numbers are reflected in the genetic algorithm by method of local search, and weights are calculated using a hybrid genetic algorithm that combines local search and genetic algorithms. A case-based reasoning model was developed using the weights calculated and validated with the data. As a result, it was found that the hybrid GA-CBR applied with local search performed better than the existing GA-CBR.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.2
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• pp.97-111
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• 2012

This study aims to find a proper construction cost calculation method by comparing unit prices of cost estimate in landscape construction among other public ordering construction projects. There were 7 out of 12 items from the actual work cost in the first half of 2011 were compared. The 12 items were classified as landscape Architectural construction and the 7 items were the approximate standard. As applied construction types, the comparable 35 items out of the 80 actual work cost items applied to 5 sites were compared to the unit price of the standard quantity per unit in March 2011, which was the approximate standard. Actual construction rate of the 7 items in the category of landscape sector was 104.86% for each item and 92.09% as a total construction cost. The high actual construction rate was caused by the high rate of seed spray depending on the status of applying rocks. However, there were more fundamental reasons for the cost generated from aslope treatment for grass and seed spray. So, it requires more detailed regulations on the modification factors for each soil type, the standard and needs to improve theillogical standard quantity per unit system. Actual construction rate of the 35 items in the applied sectors of civil engineering and architecture was 78.65% for each item and 71.31% (70.17%) as a total construction cost. This shows that actual unit cost cannot reflect actual cost structurally and standard quantity per unit system lacks practicality in terms of construction due to thelabor force. 85.1~91.2 % actual construction rate announced by the Ministry of Land and Maritime Affairs referred to the newly switched items. So the result was estimated as actual construction rate. This requires supplementation after verification in order to make the actual work cost produce at a proper rate. Also, standard quantity per unit system needs complementation with these actual data and so on.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.871-879
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• 2008

Recently, as there are a rise in the standard of living and higher concerns of an electromagnetic wave and environment, undergrounding the aerial cables which are supported by large pylons and generally considered as the least attractive feature of an urban area is on an increasing trend to improve aesthetic benefits and electric reliability. This study applied Contingent Valuation Method (CVM) which is expected to become an effective tool to measure indirect benefit to estimate the substantial benefits of undergrounding overhead power line projects in an urban area. The tunneling construction project of the 345kV Shinsungnam electric power cable in Seongnam city was selected and a hypothetical scenario was given to respondents to determine their levels of Willingness to Pay (WTP) for undergrounding overhead power lines. The result from the estimation of the WTP of undergrounding overhead power lines in Seongnam city was calculated as approximately 17.1 billion won. Placing existing overhead lines underground is difficult to justify economically. Most undergrounding costs appear to be justified by aesthetic and public policy considerations. Therefore, considering the result of this study, undergrounding overhead power lines is of great benefit to public.

• Korean Journal of Construction Engineering and Management
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• v.6 no.6 s.28
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• pp.98-106
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• 2005

The construction cost index and the forecasting model of apartment house can be efficient for evaluating the validness of the fluctuating price, and for making guidelines for construction firms when calculating their profit. In this study the previous construction cost index of apartment house was improved, and the forecasting model based on X-12 ARIMA was developed. According to the result, during the last five years the construction cost, excluding labor expense, has risen approximately to 22.7%. And during next three years, additional 16.8% rise of construction cost is expected. Those quantitative results can be utilized for evaluating the apartment house's selling price in an indirection, and be helpful to understand the variation pattern of the price.

• Tunnel and Underground Space
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• v.21 no.6
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• pp.427-438
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• 2011

Segment lining is a key permanent lining structure to maintain the shield tunnel stability in shield tunnel operation. Moreover, segment lining generally accounts for the largest proportion in the shield tunnel construction costs. As a result, technical improvements to increase its economic feasibility have been actively carried out. This study aims to propose the development directions of high-performance segments from their recent cutting technologies. In addition, based on over 2,100 world-widely collected segment design data, a series of statistical analyses of segment key design parameters such as thickness, width and the number of divisions as well as segment materials were carried out to approximately estimate them in a design stage.