• Tunnel and Underground Space
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• v.9 no.1
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• pp.20-26
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• 1999

The completion of the Bakun Diversion Tunnel is subsequently to the Main Dam construction. Therefore, the completion date is very important for the Bakun Hydroelectric Project. Generally, the tunnel lining work as a finishing phase of the tunnelling project occupies a important portion as well as an excavation and a support work of the tunnels in respect to the construction cost and period. Internal section of Bakun Diversion Tunnel is designed circular shape to reduce the roughness of the water flow with 12 meters in diameter of total length 4314.6 meters of 3 tunnels. The lining thickness is varied between 500 mm and 700 mm depending on the structural condition. From the original Tender design of the Bakun tunnels, the required quantity of steel bars was 5,985 ton designed by Reinforced Concrete (RC) through the entire tunnel linings. During the detail design stage by the consideration of the rock conditions and various load conditions, we could suggest five kinds of RC lining type including plain concrete lining type. Through the detail design modification, we could reduce the required amount of steel bars to 2,178 ton, as a half of original Bill of Quantity. Finally, this design modification give us the time and cost saving effect to catch up the construction progress in time.

• 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.

• Journal of the Korea Institute of Building Construction
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• v.10 no.6
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• pp.49-60
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• 2010

Cost Estimating allows each entity in a construction project to plan, distribute, and control its required construction cost for the project. However, existing 2D design based estimating has problems, such as inaccuracy and inefficiency caused by missing, duplicated, or erroneous calculations. In this situation, current estimations for school facilities have more difficulties in forecasting construction costs due to an inadequate work breakdown structure for BOQ (Bill of Quantity) and insufficient guidelines for Basis of Estimate. In this study, therefore, an effort was made to increase the efficiency of estimating for school facilities by applying a 3D modeling based BIM tool to quantity and cost estimates. In addition, this study suggested a reasonable work breakdown structure for BOQ that was appropriate when 3D modeling was applied, and verified it through a case study. The authors tried to provide a BIM-based estimating method for school facilities to obtain greater accuracy and efficiency by having more information in an earlier stage.

• Korean Journal of Construction Engineering and Management
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• v.20 no.6
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• pp.89-97
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• 2019

Recently, BIM has been actively introduced in construction projects. In particular, the introduction of BIM in cost estimating process is expected to improve the accuracy and efficiency of the cost estimate. However, the quantity calculation and BoQ documents preparation process still require manual work. Although the BIM model may support quantification process, it is still problematic that the level of detail of the model must be very detailed to meet the items in BoQ. To address this, it is necessary to analyse the LOD criteria and to analyze the extent to which quantity can be computed according to the level of detail in the BIM model. For the analysis of LOD-based work items, the work item grades were divided into A,B, and C. In this study, the ratio and cost of each item that can be calculated at the LOD level in the detailed design phase are reviewed for each type of work, and the method for improving the quantity calculation using BIM is proposed. In the LOD 300 stage(Detailed design stage), the largest number of items in the class B, the major improvement class, are window and glass work. In addition, the most expensive type of work was analyzed by reinforced concrete work. In the future, it is necessary to suggest appropriate improvement way for items with high item ratios and items with high cost ratios. The results of this study are expected to be used as a BIM-based cost estimation or as basic data for improving the current BoQ system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.105-113
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• 2006

Construction cost index is generally used to estimate the new project cost based on past construction data and to adjust the contract cost when the price change of various articles and items of expenditure composing the contract occurs. In Korea, it is mostly used for modulation of construction contract cost due to fluctuation of prices. However the method for making cost index had some problems in calculating cost index of each expenditure item that could not properly reflect the change of construction cost. To supplement these problems, the research of developing construction cost index has been executed. Through the precedent research, these problems were partially resolved but still remain. Therefore this research proposes the method for making cost index that utilizes representative items of labor, material, equipment by analyzing bill of quantity of road construction, through analysis and comparison of precedent studies. By using this method, it is expected to solve the problems which were not reflected in preceeding studies.

• Korean Journal of Construction Engineering and Management
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• v.8 no.6
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• pp.178-187
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• 2007

As the government has enforced recently the policies on the distribution of the housing, the construction cost of multi-family housing projects has increasingly become very sensitive and political issue. However, it is difficult to predict the construction cost in planning and design phase of the project because the Bill of Quantity of the multi-family housing projects was composed of breakdown structure based on each work package. To predict the construction cost in planning and design phase for multi-family housing projects in more effective and reasonable way, this study developed the cost breakdown structure based on spaces using Delphi method. The Cost Breakdown Structure (CBS) based on spaces for multi-family housing projects basically consists of three parts: (i) Building part; (ii) Non-building part; and (iii) Additional part. The characteristics of spaces in multi-family housing projects are fully taken into consideration. Then these three parts were subdivided into work packages in terms of work tasks. Additionally, the usefulness and effectiveness of Space CBS in this paper were validated by analyzing the BOQs of several collected sample projects and matching with Space CBS afterwards.

• Korean Journal of Construction Engineering and Management
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• v.11 no.1
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• pp.160-169
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• 2010

In domestic public works, there are several problems in the measurement of payments based on the bill of quantity, which doesn't match with the activity progress rate, heavy paper works and complicated procedures. It can be classified formal and simplified method. By using the simplified method, it can be solved many problems by summarizing the procedure, but is not generally used. This paper proposes a payment method by progress measurement for specified activity based on WBS(Work Breakdown Structure) verifying efficiency which reduced cost account and advanced work on payment compare to method of domestic public works using the data about construction of eco-river. This method will be an important contribution on being a base for cost-schedule integrated management which were verified and also improving efficiency on measuring payment.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.5
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• pp.428-434
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• 2016

A lot of drawings for pipe construction and installation are needed to construct plant process system on the offshore plant structures. Depending on their scale or complexity, the required number of drawings related pipes sometimes amounts to several hundreds of thousands. Most major shipyards, therefore, have their own system which can automatically depict pipes’ geometric, manufacturing, and BOM(Bill of Material) information on the drawings. However, as the complexity and absolute quantity in the isometric region on the drawings is increased, the information extraction from the customized DB and positioning at the typical locations does not get to be enough to avoid the overlap between geometric contours, labels, and symbols. For this reason, the novel methods to arrange additional annotations without overlaps are presented in the paper. This approach is expected to increase the readability and legibility of the drawing and prevent the human error, and finally decrease the time-consuming and tedious jobs which are unnecessarily required to designers.

• Korean Journal of Construction Engineering and Management
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• v.13 no.3
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• pp.99-108
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• 2012

The rough design information is only available from BIM(Building Information Model) based schematic design. So, it is difficult to obtain sufficient information for generating BOQ. Like 2D design, there are some problems that the results are depend on what the choice of cost estimator. However, the most research of BIM based cost estimation are focus on quantity takeoff, the consideration of work item for generating BOQ is insufficient. Therefore, this paper present automatic inference process of work items in a BOQ using ontology. The proposed process and ontology is validated through applying tiling construction. If the proposed process is utilized, it is expected the basis of developing generation method for consistent BOQ by resolving intervention of cost estimator's arbitrary decision.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.297-305
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• 2016

This study aims to analyze characteristics of environmental load for the construction phase of PSC beam bridge based on Life Cycle Assessment. For detail computation of environmental load, the construction materials and energy consumption are derived from the BOQ, also connecting with environmental load by Korea LCI Database Information Network. The characteristic of environmental impact was analyzed by 25 cases and cut-off ratio was 80% to 94%. The result sorted by construction materials revealed that environmental load were 53.3% for ready-mixed concrete, 9.6% for wire rod, 7.8% for rebar, 6.8% for cement, 5.5% for plywood, and 5.2% for energy. Furthermore, the result of environmental impact revealed that 45.5% for global warming, 30.4% for abiotic resources depletion, 10.5% for human toxicity, and 8.9% for photochemical oxidant creation. In the future, we can make a decision considering environmental load based on LCA at design phase.