• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.35-44
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• 2010

For efficient maintenance management of bridges, an establishment of asset management system is necessary which helps prediction of maintenance cost and strategic allocation of budget in consideration of top priority. The main purpose of this study is to suggest asset valuation method, which is practical in conformity with domestic situations, through researches on asset valuation method of bridges. This study has researched asset valuation method of bridge, which is appropriate for domestic situations by finding out advantages and disadvantages through investigating domestic and foreign application examples of asset valuation method for bridge facilities. In this study, asset valuation method by historical cost and replacement cost were suggested and a valuation model for bridges was established. In addition, two suggested valuation methods were applied to actual bridges which is used in Korea. As the result, it was analyzed that bridge asset valuation method in consideration of historical cost is desirable for the accounting purpose. And, it was analyzed that valuation method utilizing depreciated replacement cost(DRC), which could consider various factors, is desirable for the maintenance decision supporting purpose.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.317-322
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• 2004

As a construction project in urban area tends to be high-rise and huge, the importance of the project's underground work, in terms of the cost and the schedule, is gradually increasing. It's extremely significant to choose a proper filing method, at the stage of underground work. However, in piling work many change orders have been occurred since a piling method is experientially selected based on uncertain information and many earth factors to consider. It has effects on the cost and the schedule of the project. In this study, we have suggested a decision model for piling method that can be used to determine and verify the suitable piling method in design and pre-construction phase of a project. Based on historical data, a neural network model has already proven to be efficient. The tests of the model for selecting a suitable piling method have progressed exactly with the data of 150 piling works which were done room 2000 to 2004 in Korea. The optimization or the developed neural network model has progressed with the data for teaming. The validity of the neural network model has been verified.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3D
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• pp.457-468
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• 2011

Recently, the non-vibration mass excavation method is used on sewage pipes and road construction sites in Jeju. However, a construction cost estimation based on the unit quantity does not provide a proper unit price. In this study, a comparison of the productivity of the standard quantity-per-unit costing method and the one of the work crew combination method was made based on the site monitoring of the non-vibration mass excavation method that is used in construction sites near Jeju. For this, data of 35 sites were collected: a regression equation was derived from the 30 data, and verification was carried out through the remaining 5 data. The analysis concluded that a day's workload is $16.43m^3$. In addition, a combination of the equipment considering the site conditions and the amount of labor, which varies with the number of work crew was obtained in order to estimate the construction cost of the work crew combination method. The construction cost was calculated based on the one-day workload ($16.43m^3$) derived from the regression analysis. The cost then was analyzed and compared with the standard quantity-per-unit costing method.

• Korean Journal of Heritage: History & Science
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• v.50 no.4
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• pp.82-103
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• 2017

Systems operating construction expenses for preservation and repair of the architectural heritage may be divided into two in the Japanese colonial era. They are preservation cost nd preservation cost-aided constructions, according to the ownership of a building. Preservation cost construction refers to preservation and repair of government-owned buildings that Japanese Government General of Korea had the ownership and the right of management, and preservation cost-aided construction means preservation and repair of private buildings such as Buddhist temples. In the case of preservation and repair of buildings owned by the government, it was done by the Japanese Government General of Korea, so the same agent executed the budget and managed the properties. They included royal tombs and relics, old government offices, Hyanggyo and some Seowon. On the other hand, in the case of preservation and repair of private buildings, they were private properties, so Japanese Government General of Korea had rights only for permission of preservation and repair. If there was a request for .preservation and repair by an owner, the Japanese Government General of Korea decided on whether it would support its expenses or not and played a role of management and supervision. It applied to Buddhist shrines and pagodas owned by Buddhist temples and shrines and temples owned by individuals and families. Hence, in the case of government-owned buildings, because the preservation cost was spent from the Japanese Government General of Korea's budget for investigation expenses of historical remains or repair expenses of Jeolleung and ruins, they were classified into preservation cost constructions. As for private buildings, the cost was spent from their budget for aiding preservation expenses, so they were classified into preservation cost-aided constructions. Because preservation cost construction and preservation cost-aided construction were conducted by two different agents, there were a little difference in procedures for executing a construction. There was no big difference in the general progress of constructions but was an administrative difference in the kinds of documents submitted and the roles of field supervisors. Such dual systems remained unimproved throughout the Japanese colonial era. The Japanese Government General of Korea was the colonial government so much influenced by the Japanese Government. Most Japanese architectural heritage was owned by Buddhist temples and Shinto shrines and there was almost no building owned by the government, resulting in a unitary system unlike Korea. Heritage system by the Japanese Government General of Korea was established under the influence of Japan regardless of the situation in Korea. Accordingly, Japanese Government General of Korea could not present a definite solution in the bisected system of preservation and repair expenses for the heritage. It shows the limits of the Japanese Government General of Korea in the colonial era.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.654-657
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• 2008

Recently, construction projects have become bigger and complicated and the construction business scale has enlarged. Therefore a project cost size is increasing. The historical data can be easily saved by advanced technologies of IT industries. Utilizing those make us to be able to manage construction project more effectively. These days, PMIS (Project Management Information System) has supplied widely at construction companies for integrating cooperation system of Web environment. and it is being used. However the most PMIS is limited at construction phase. Actually it isn't applied to a construction project Life-Cycle(planning, design, construction and maintenance). To control manage a construction project Life-Cycle effectively, BPMS (BIM-based PMIS Modeling) should be considered. This paper suggests the ways for applying BPMS.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.109-113
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• 2007

This paper introduces a system, Simulation based Stochastic Markup Estimation System (S2ME), for estimating optimum markup for a project. The system was designed and implemented to better represent the real world system involved in construction bidding. The findings obtained from the analysis of existing assumptions used in the previous quantitative markup estimation methods were incorporated to improve the accuracy and predictability of the S2ME. The existing methods has four categories of assumption as follows; (1) The number of competitors and who is the competitors are known, (2) A typical competitor, who is fictitious, is assumed for easy computation, (3) the ratio of bid price against cost estimate (B/C) is assumed to follow normal distribution, (4) The deterministic output obtained from the probabilistic equation of existing models is assumed to be acceptable. However, these assumptions compromise the accuracy of prediction. In practice, the bidding patterns of the bidders are randomized in competitive bidding. To complement the lack of accuracy contributed by these assumptions, bidding project was randomly selected from the pool of bidding database in the simulation experiment. The probability to win the bid in the competitive bidding was computed using the profile of the competitors appeared in the selected bidding project record. The expected profit and probability to win the bid was calculated by selecting a bidding record randomly in an iteration of the simulation experiment under the assumption that the bidding pattern retained in historical bidding DB manifest revival. The existing computation, which is handled by means of deterministic procedure, were converted into stochastic model using simulation modeling and analysis technique as follows; (1) estimating the probability distribution functions of competitors' B/C which were obtained from historical bidding DB, (2) analyzing the sensitivity against the increment of markup using normal distribution and actual probability distribution estimated by distribution fitting, (3) estimating the maximum expected profit and optimum markup range. In the case study, the best fitted probability distribution function was estimated using the historical bidding DB retaining the competitors' bidding behavior so that the reliability was improved by estimating the output obtained from simulation experiment.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2120-2121
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• 2011

현재 정부가 추진하고 있는 전기분야 실적공사비 적산제도와 관련된 최근의 움직임은 당초의 취지와 달리 실적공사비에 대한 개념 부족과 임의적 해석 등으로 실적공사비 적산제도 도입의 바람직한 방향성에도 불구하고, 실적단가 축적의 기초 자료인 계약내역서의 직접 공사비 낙찰률 적용 관계 등 실적단가의 적정성에 대한에 근본적인 접근보다 예산절감, 물가안정 측면으로 접근하여 시장단가 반영에 대한 왜곡현상이 발생 할 수 있는 제도상의 문제점으로 실적단가 축적에 대한 적정성 판단에 따른 실적단가의 보정 수단이 미약하여, 현행 법제도 하에서 실적단가의 적정성 확보를 위한 대응 방안을 제시하여 실적공사비를 정착시킬 필요가 있다. 왜냐하면 품셈에 의한 문제점 등으로 실적공사비 적산제도로 공공 건설공사의 예정가격산정 방식을 전환 하였다고 볼 때, 본 제도의 실패는 또 다른 제도로의 전환 또는 보완이 필요하다고 판단된다.

• Korean Journal of Construction Engineering and Management
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• v.19 no.1
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• pp.74-79
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• 2018

The establishment of an effective bidding system is critical to ensure both the high quality of civil infrastructure and proper earning of contractors. However, the continuous changes of a bidding system in South Korea reveal that problems such as a dumping or high price winning have not been fully resolved yet. This study thus aims at understanding the bidding behavior and strategies of contractors by analyzing a tender ratio in historical data. Multiple regression analysis is conducted to understand the effect of internal and external factors (e.g., estimated cost, combined value of construction performance evaluation) on a tender ratio. The results statistically show that such factors affect the tender ratio an individual bidder determines and have the varying effect on the tender ratio by contractors' firm size.

• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.70-79
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• 2016

The current remodeling cost estimation process is not only dependent on the historical data of new building construction, but it also has a poor linkage with risk-based estimation approach. As such, there is a high risk of falling short of initial budget. To overcome this, a risk-based estimation approach is necessary by providing a probabilistic estimation in consideration of the potential risk factors in conducting the remodeling projects. In addition, the decision-making process should be linked with the risk-based estimation results in stead of intuitive and/or experience-based estimation. This study provides a probabilistic estimation process for residential remodeling projects by developing a detailed methodology in which a step-by-step approach can be achieved. The new proposed estimation approach can help in decision-making for remodeling projects in terms of whether to proceed or not, by effectively reflecting the potential risk factors in the early stage of the project. In addition, the study can enhance the reliability of the estimation results by developing a sustainable estimation process model where a risk-based evaluation can be accomplished by setting up the cost-risk relationship database structure.

• Journal of architectural history
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• v.15 no.1 s.45
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• pp.7-27
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• 2006

This study aims to identify and analyze the factors that influenced the construction of London Eye which was led by private groups, including characteristics in progress, differentiated value in design, the combination of technology and design, and construction costs. The results of this study were the followings. 1) London Eye provides a new construction method for a landmark in the downtown in that the architects became the clients of the project which might have been hoarded, procuring the construction costs and completing it by themselves. 2) London Eye presents a space utilization method where undeveloped spaces in the downtown are used in three-dimensions by erecting a structure on the river with a minimum land. 3) The process of design, production and erection is propelled the realization of technical intention design with one system and from at the initial stage, the participation of the engineer where the designer is equal with you must accompany. 4) London Eye is endowed with strong shape by a circle in design concept, which is the simplest geometrical figure, and it provides organic relationship between the past and the present by utilizing historical elements in various ways. 5) The construction was completed through four phases including idea phase, promotion phase, turn-key contract phase, and design-build phase. The most critical factor to the success is derived from the direct contact with Involved companies from the production phase. 6) In a project facing many challenges in terms of technology, the design-build method proves to be a more effective method than turn-key contract in that it may more allocate risks and enable coherent implementation of the core concept in design. The organization for the design-build method was composed of three phases including general affairs, responsible contracting by sector, and cooperative system by sector. Since that was a new concept structure, high-level contractors who hadn't had existing cooperative relationships with one another formed new cooperative relationship, while collaborating companies who had long cooperated led the responsible contracting and sub-cooperative system, which resulted in reduction of risks and time. 7) The major factors to change design were the design characteristics, derived from a technically great combination, and the opening time. 8) A new erection method was applied to London Eye, a structure that overcame the limitation in land and period, and the process of installation demonstrated that it is an important value for the construction of a landmark in the city. 9) In spite of many visitors and tremendous operational income, the factors that London Eye fails to free itself from debts include the construction costs expended double than expected, and interest burden to the investments, which occurred in the course of procuring the costs. Absolute limit in time increased the construction costs, resulting in being a great obstacle in the course of operation.