• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.201-211
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• 2003

Considering about construction projects characteristics, there Is an existing uncertainty which causes inaccuracy or invalidity under decision making situation. Therefore, cost risk analysis of numerous construction projects are Inclined to depend on expert's experiences and subjective judgements. In Korean domestic construction works, however, there is no reasonable method or process for applying subjective elements. Only probabilistic analysis using objective calculation are being used now. This research suggests a cost risk analysis method to analyze quantitatively Cost Impact by risk, and it appraises expert's subjective elements for the purpose of enhancing validity of cost estimation. Moreover, a new cost risk analysis method is introduced for providing convenient user interface in practical business.

• Structural Engineering and Mechanics
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• v.36 no.4
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• pp.513-527
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• 2010

This paper presents a three-dimensional finite element method based structural analysis model for structural analysis of reinforced concrete high-rise buildings during construction. The model considered the time-dependency of the structural configuration and material properties as well as the effect of the construction rate and shoring stiffness. Uniaxial compression tests of young concrete within 28 days of age were conducted to establish the time-dependent compressive stress-strain relationship of concrete, which was then used as input parameters to the structural analysis model. In-situ tests of a RC high-rise building were conducted, the results of which were used for model verification. Good agreement between the test results and model predictions was achieved. At the end, a parametric study was conducted using the verified model. The results indicated that the floor position and construction rate had significant effect on the shore load, whereas the influence of the shore removal timing and shore stiffness have much smaller. It was also found that the floors are more prone to cracking during construction than is ultimate bending failure.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.637-642
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• 2007

The sum of each work duration are entire period in construction project. Each work occurs to be late, the total period of construction project will delays. Therefore, the total period of construction project will not be delayed if probability of working progress makes higher. Finding each work's constraints performs constraints analysis in process of construction for checking probability of working progress. Grasp work's constraints through the constraints analysis and removes. This research will show preventing delay of consruction project, through constraints analysis process.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.678-679
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• 2015

Recently, safety accidents in construction sites are increasing. Accordingly, in this study, development of 'Big-Data Analysis Modeling' can collect articles from last 10 years which came from the Internet News and draw the cause of accidents that happening per season. In order to apply this study, Web Crawling Modeling that can collect 98% of desired information from the internet by using 'Xml', 'tm', "Rcurl' from the library of R, a statistical analysis program has been developed, and Datamining Model, which can draw useful information by using 'Principal Component Analysis' on the result of Work Frequency of 'Textmining.' Through Web Crawling Modeling, 7,384 out of 7,534 Internet News articles that have been posted from the past 10 years regarding "safety Accidents in construction sites", and recognized the characteristics of safety accidents that happening per season. The result showed that accidents caused by abnormal temperature and localized heavy rain, occurred frequently in spring and winter, and accidents caused by violation of safety regulations and breakdown of structures occurred frequently in spring and fall. Plus, the fact that accidents happening from collision of heavy equipment happens constantly every season was acknowledgeable. The result, which has been obtained from "Big-Data Analysis Modeling" corresponds with prior studies. Thus, the study is reliable and able to be applied to not only construction sites but also in the overall industry.

• Proceedings of the Korean Geotechical Society Conference
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• 1997.10a
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• pp.203-210
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• 1997

• International conference on construction engineering and project management
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• 2009.05a
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• pp.230-236
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• 2009

Double-front construction machinery, which was designed for complicated tasks, requires intelligent systems that can provide the quantitative work analysis needed to determine effective work procedures and that can provide operational and cognitive support for operators. Construction work environments are extremely complicated, however, and this makes state identification difficult. We therefore defined primitive static states (PSS) that are determined using on-off data for the lever inputs and manipulator loads for each part of the grapple and front and that are completely independent of the various environmental conditions and operator skill levels. To confirm the usefulness of PSS, we performed experiments with a demolition task by using our virtual reality simulator. We confirmed that PSS could robustly and accurately identify the work states and that untrained skills could be easily inferred from the PSS-based work analysis. We also confirmed in skill-training experiments that advice information using PSS-based skill analysis greatly improved work performance. We thus confirmed that PSS can adequately identify work states and are useful for work analysis and skill improvement.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.3
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• pp.275-283
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• 2010

Recently, the observational design and construction method in tunnels has been becoming important. Rock masses include various discontinuities such as joints, faults, fractures, bedding planes, and, cracks. The behavior of tunnels in hard rocks, therefore, is generally controlled by various discontinuities. In this study, a new key block analysis method for observational design and construction method in tunnels is proposed, and then applied to the actual tunnel with a super-large cross-section. The proposed analysis method considers finite persistence of discontinuities. The new analysis method can handle concave and convex shaped blocks. To demonstrate the applicability of this key block analysis method for observational design and construction method in tunnels, the analysis results are examined and compared with those of the conventional method.

• Computers and Concrete
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• v.14 no.5
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• pp.599-612
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• 2014

This paper presents the effects of the construction stages using time dependent material properties on the structural behaviour of concrete arch dams. For this purpose, a double curvature Type-5 arch dam suggested in "Arch Dams" symposium in England in 1968 is selected as a numerical example. Finite element models of Type-5 arch dam are modelled using SAP2000 program. Geometric nonlinearity is taken into consideration in the construction stage analysis using P-Delta plus large displacement criterion. In addition, the time dependent material strength variations and geometric variations are included in the analysis. Elasticity modulus, creep and shrinkage are computed for different stages of the construction process. In the construction stage analyses, a total of 64 construction stages are included. Each stage has generally $6000m^3$ concrete volume. Total duration is taken into account as 1280 days. Maximum total step and maximum iteration for each step are selected as 200 and 50, respectively. The structural behaviour of the arch dam at different construction stages has been examined. Two different finite element analyses cases are performed. In the first case, construction stages using time dependent material properties are considered. In the second case, only linear static analysis (not considered construction stages) is taken into account. Variation of the displacements and stresses are obtained from the both analyses. It is highlighted that construction stage analysis using time dependent material strength variations and geometric variations has an important effect on the structural behaviour of arch dams. The maximum longitudinal, transverse and vertical displacements obtained from construction stages and static analyses are 1.35 mm and 0 mm; -8.44 and 6.68 mm; -4.00 and -9.90 mm, respectively. In addition, vertical displacements increase from the base to crest of the dam for both analyses. The maximum S11, S22 and S33 stresses are obtained as 1.60MPa and 2.84MPa; 1.39MPa and 2.43MPa; 0.60MPa and 0.50MPa, respectively. The differences between maximum longitudinal, transverse, and vertical stresses obtained from construction stage and static analyses are 78%, 75%, and %17, respectively. On the other hand, there is averagely 12% difference between minimum stresses for all three directions.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.459-462
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• 2015

Korean construction industry made a huge growth over several decades. However, domestic construction market has shrunk in recent years due to the domestic political environments and global economic crisis. Today, the international construction markets become more important to be investigated, and demands for international construction study have risen. The purpose of this study is to search for measures to compare the potential of Southeast Asian countries' construction markets and select strategic target countries where the Korean construction companies pursue to explore for future investments. The research team investigated a range of selection factors which can represent the construction market condition of each country. These factors included the size of the construction industry, economic growth potential, current relationship with Korea, the level of infrastructure development, political situation, etc. After collecting data, each selection factor was scored by experts' analyses and the total score was given to each country. As a result, the rating identified attractive countries for future investments: Myanmar, Vietnam, and Sri Lanka. For the target countries, analytical methods were used for in-depth market analysis that can provide comprehensive insight and strategic clue for development of short-/mid-/long-term roadmap and action plans. The research findings would be used to support rational decision making of construction investment advancing to the Southeast Asian economic growth.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.315-320
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• 2013

The aim of this study is to compare efficiency and Total Factor Productivity(TFP) between Korean and Japanese construction firms in Korea and Japan over the period of 2005-2011. The results of this study are as follows. Efficiency scores of Korean construction firms are 0.797, and Japanese construction firms are 0.921. Second, annual total factor productivity growth of Korean construction firms is 0.5% and technical progress do much for TFP decrease. However Japanese construction firms marked annual increasing of 2.5% of TFP. Third, technical progress contributed in TFP increase of construction firms in Korea. Korean construction firms, however, relatively lagged behind Japanese construction firms in technical progress. Therefore, Korean construction firms need strategies to achieve technical advances including adopting new technology or process innovation to maintain competitiveness, survive, and develop in the future competition with Japan.