• Tunnel and Underground Space
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• v.11 no.1
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• pp.14-19
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• 2001

The estimation of proper prediction method and the transformation method of environmental regulation standard were carried out by measuring blasting vibration. Vibration velocity was more adequate than vibration level in the blasting design by scaled distance. Thus, design and construction mutt be controlled by vibration velocity, and it is required that the vibration velocity is transformed to vibration level to meet regulation standard. Three transformation methods were studied. First, transformation formula is derived from the shock vibration data only. The second method it the transformation by correlation equation of vibration velocity and vibration level measured at the same time. The last one is the transformation of vibration velocity by FFT. It seems to be difficult to estimate damages by these methods because that every method shows considerable error. But transformation formula of PPV component to vibration level was most practical.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1244-1249
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• 2005

Present PII(Private Infrastructure Investment) in Korea has increased up to 11% compared to the year 2003 and is expected to increase in the future. In spite of its rapid increase, we don't have any definite standard or system which distinctly presents the rate of return for domestic PII yet, and practical and scientific research is not sufficient compared to its necessity and importance. Hence, in this study we suggests methods to estimate the rate of return of PII to promote SOC PII to last successfully and present the proper level of rate of return of PII which is appropriate for domestic situations through diverse analysis. Therefore, to present reasonable rate of return, we have used 5 methods: previous research analysis, case study, financial index analysis, analysis of investor's rate of return, and analysis of rate of return in a real estate market. After comparing and analyzing these methods, at the end, we have presented the appropriate level of rate of return of PII, which can be applied in the domestic market.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1678-1688
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• 2008

In this study, dredging reclamation ground were performed to evaluate the ground improvement and liquefaction reduction effect with the result that standard penetration test(SPT) and piezo penetration test(CPT) before and after of improvement. Especially, the estimate center of the pile and factor of liquefaction safety to the position of ground around with the pile presented improvement of compaction for improved compaction of dredging reclamation ground.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.48-49
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• 2014

Green Frame is a column-beam system that uses composite precast concrete members. Previous studies have proven this system to be not only structurally safe, constructible, and economically feasible, but also environmentally-friendly. If the computerized program is used to estimate the quantity, the result of it shall be calculated much easily, quickly and exactly than manual estimation, because precast concrete members of Green Frame has standard size and connection method between it. Therefore, this study suggest quantity survey concept for column-beam structure comprised of composite precast concrete members. Hereafter, the quantity survey of Green Frame shall be much quickly and accurate, if the system would be made based on the result of this study.

• Korean Journal of Construction Engineering and Management
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• v.9 no.6
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• pp.235-243
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• 2008

Construction projects have unique characteristics that these may be carried out by contractors thus, cost should be estimated before execution. The importance of cost estimation and cost check has become increasingly emphasized in all phases of construction project that would be performed numerously. It is needed that owner have to estimate reasonable budget, and contractor should predict the bid price. However, there are lack of standard cost estimation method before quantity takeoff, cost analysis method, and cost database thus, the method of area cost, such as square foot method, is as used as ever in Korea. Therefore, this research suggested standard cost database structure CUBE, and analysis method of item quantity per one household categorized by area type. Whereafter, database of all item quantity of finish work has been built with 90 building cost data, and validated it's availability. In this respect, the suggested method and the findings from this research are expected to help enhancing the efficiency and productivity of cost estimation in Korea.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.143-152
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• 2016

To estimate the stability of a debris flow it is necessary to know the mass of surface soil, cohesion, slope, and friction angle. Given that the mass of surface soil is a function of soil thickness and mass density, it is important to obtain reliable estimates of soil thickness across a wide area. The objective of this paper is to estimate soil thickness using the elastic wave velocity with a new standard velocity. Tests are performed in debris-flow hazard areas, after which four profiles are selected to obtain the elastic wave velocity. Dynamic cone penetration tests are carried out to find the soil thickness at 18 points. The elastic wave velocity shows the area consists of 3~4 layers, and soil thicknesses are predicted by utilizing the new standard. The elastic wave velocity and dynamic cone penetration tests yield large differences in soil thickness. Therefore, this study shows that the new standard is useful not only in estimating soil thickness but also in improving the reliability of estimates of soil thickness.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5D
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• pp.677-684
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• 2008

The paper provides an approximate cost estimating model that can be used for tunnel. Based on the previous study analyzed critical factors that have impact on tunnel construction cost, this paper establishes a cost variance index table that reflects the cost impacts due to the change of the critical cost factors. An estimating procedure is described utilizing the index table. For the verification of the suggested model, the comparison of the estimated construction cost with real project cost is performed. The estimated results range from 95%~111% of the real project costs. As an approximate tunnel cost estimating model, the model can be utilized to quickly estimate tunnel construction costs based on the conceptual information at the planning stage and to efficiently make a decision on design alternatives.

• Journal of the Society of Disaster Information
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• v.8 no.4
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• pp.319-327
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• 2012

This research collected work drilling report of TBM method site developed by WRITH company to TBM equipment company in Germany and analyzed work operating productivity. Based the data analyzed TBM operating productivity, This research derived and presented excavation speed(m/day) by TBM diameter (2.6m, 3.0m, 3.5m, 5.0m, 8.0m) and rock. Also, based on the excavation speed(m/day) by TBM diameter, This research estimated a day direct construction cost and total direct construction costs by applying a direct construction cost which spent on per 1m. Based on hard rock 40.0%, soft rock 30.0%, usually rock 20%, weathered rock 10.0%, TBM boring velocity, m per cost, total construction period shall estimate the construction cost and the construction period by the effective use by diameter when future applying TBM method to the basic planning stages and in the preliminary design phase.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.4
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• pp.53-62
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• 2012

U-City means the high-tech city that applied ubiquitous technology and information communication technology. U-City aims to intensify urban competitiveness and to improve the quality of residents' life through efficient management of the urban. Currently, 77 U-City projects is underway. The each project cost and scale estimate is not clear in the absence of the U-Service Standardization Model. So, many of the project are trouble about making a production the proper number of U-Service or the cost of project. The excessive service construction is reflected on the construction costs, which leads to the rise of sales price and passes onto the executor of a project as a burden of the project costs, and the problem of the delay of the change-over occurs due to supporting the operation costs for the operation of the constructed service and the demand for additional installation of facilities between a local autonomous entity and the executor of a project. In this paper, we suggested the U-Services Construction Standardization Methods and proposed the standardization services guideline of crime prevention services. U-City services in the future are able to maintain the consistency of the system through the utilization of the proposed standard model. As a result, the U-City project's pre-estimated cost and scale can be extracted.

• International Journal of Concrete Structures and Materials
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• v.2 no.1
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• pp.57-62
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• 2008

When the yield line theory is used to estimate the ultimate strength of a concrete barrier, it is of primary importance that the correct assumption is made for the failure mode of the barrier. In this study, a static test was performed on two full-scale concrete barrier specimens of Korean standard shape that simulate the actual behavior of a longitudinally continuous barrier. This was conducted in order to verify the failure mode presented in the AASHTO LRFD specification. The resulting shape of the yield lines differed from that presented in AASHTO when subjected to an equivalent crash load. Furthermore, the ultimate strengths of the specimens were lower than the theoretical prediction. The main causes of these differences can be attributed to the characteristics of the barrier shape and to a number of limitations associated with the classical yield line theory. Therefore, a revised failure mode with corresponding prediction equations of the strength were proposed based on the yield lines observed in the test. As a result, a strength that was more comparable to that of the test could be obtained. The proposed procedure can be used to establish more realistic test levels for barriers that have a similar shape.