• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1937-1944
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• 2014

In recent years, common ducts have been installed and operated in the sidewalls of tunnels to prepare for emergencies in tunnel construction and maintenance. The installation of common ducts is done mainly by humans. Problems with cost increases are inherent in tunnel construction by humans due to the safety risks and the economic inefficiency of humans performing construction activities. Among the problems that arise are poor illumination due to the use of temporarily installed electricity, the risk of accidents due to the confined workspaces, and workers avoiding work tasks because of the poor environment in tunnel. Ideas for solving these problems were developed using a value engineering (VE) process, and mechanized construction was identified as a promising solution. To verify the effectiveness of mechanized construction of a common duct in tunnels, experimental construction work was carried out, and mechanized construction was proven to directly improve the constructability and economic efficiency of common duct construction. In addition, reducing human involvement in common duct construction in tunnels is expected to improve safety, and because of the continuous concrete placement technique used, the finish and appearance of the ductwork are improved.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.117-122
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• 2006

In spite of various approaching method to satisfy with the owner's requirements in schematic design phase, it is insufficient to evaluate intermediate process of design arithmetically with participating in design process. So the numerous changes of design after completion of design development cause a lot of loss to the design company. The designer arranges owner's requirements to prevent from this loss at the initial stage of schematic design phase systematically and lets owner and stakeholder to evaluate the value of schematic design to satisfy with owner's and stakeholder's requirements. If the evaluated value for schematic design is above a definite value index, the next design phase should be advanced. By this method, the design company can reduce the additional expenses remarkably by preventing with re-design which is occurred by not reflecting owner's intention or by changing owner's intention. Also the designer have the owner to evaluate the result of design and construction. The designer let the owner know whether the owner's requirement should well have been reflected on drawing or not. There is a strong point to be able to minimize the criticism which can be occurred after completion of construction by evaluating for owner's satisfactory degree and by having owner and designer confirm the result of design and construction arithmetically. This paper presents that the loss of design company can be minimized by going over at next step if the value is over a definite value index after evaluating value for each design from design process.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.3-10
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• 2022

An estimated investment gap of $176 billion needs to be filled over the next ten years to improve America's inland waterway transportation systems. Many of these infrastructure systems are now beyond their original 50-year design life and are often behind in maintenance due to funding constraints. Therefore, long-term maintenance strategies (i.e., asset management (AM) strategies) are needed to optimize investments across these waterway systems to improve their condition. Two common AM strategies include policy-driven maintenance and performance-driven maintenance. Currently, limited research exists on selecting the optimal AM approach for managing inland waterway transportation assets. Therefore, the goal of this study is to provide a decision model that can be used to select the optimal alternative between the two AM approaches by considering key uncertainties such as asset condition, asset test results, and asset failure. We achieve this goal by addressing the decision problem as a single-criterion problem, which calculates each alternative's expected value and certain equivalence using allocated monetary values to determine the recommended alternative for optimally maintaining navigable waterways. The decision model considers estimated and predicted values based on the current state of the infrastructure. This research concludes that the performance-based approach is the optimal alternative based on the expected value obtained from the analysis. This research sets the stage for further studies on fiscal constraints that will effectively optimize these assets condition.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.2
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• pp.103-110
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• 2002

An artificial neural network is applied to the prediction of compressive strength, slump value of concrete. Standard mixed tables arc trained and estimated, and the results are compared with those of experiments. To consider the varieties of material properties, the standard mixed tables of two companies of Ready Mixed Concrete are used. And they are trained with the neural network. In this paper, standard back propagation network is used. For the arrangement on the approval of prediction of compressive strength and slump value, the standard compressive strength of 210, $240kgf/cm^2$ and target slump value of 12, 15cm are used because the amount of production of that range arc the most at ordinary companies. In results, in the prediction of compressive strength and slump value, the predicted values are converged well to those of standard mixed tables at the target error of 0.10, 0.05, 0.001 regardless of two companies.

• Architectural research
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• v.21 no.2
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• pp.49-57
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• 2019

Risk assessment during pre-construction phase is important due to the uncertainty of the risks that may exist in projects. Risk checklist is a method to systematically classify and organize the risks that have been experienced in the past, and to identify the risk factors that may be present in the future projects. In addition, risk value assessment based on checklists plays a key role in risk management, and various risk assessment researches have been conducted to carry out this systematically. However, previous approaches have limitations in common, this is because risk values are evaluated individually in risk checklists, which ignore interdependencies among risk factors and neglect the emergence of co-occurrence of risks. Hence, when multiple risk factors cooccur, they cannot be far off from the conventional method of summing the total risk value to establish the risk response strategy. Most of risk factors are interdependent and may have multiple effects if occurred than expected. In particular, specific cause can be overlapped if multiple risks co-occur, and this may result in overestimation of the risk response for the future project. Thus, the objective of this research is to propose a model to help decision makers to quantify the risk value reflecting the interdependency during the identification phase using existing risk checklist that is currently being practiced in actual construction projects. The proposed model will provide the guideline to support the prediction and identification of the interdependency of risks in practice. In addition, the better understanding and prediction of the exceeding risk response by co-occurring risks during the risk identification phase for decision makers.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.445-449
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• 2015

Construction industry is one of the most significant sector in national economic, but the portion of construction has been falling regularly with the regional development. In spite of decrease in economic portion, role of construction industry does not changed irrespective of development, as the foundation of development. To distinguish each state of the maturity, countries are grouped on GDP per capita, than compared with variance of GVA in construction and GFCF per GDP as level of construction industry. GVAc% and GFCF% shows corn-shaped plotting in increase of GDP per capita, and each value converge to around 20% and 5% as GDP per capita increase. The definition of maturity is consist of 4 stages; pre-developing, ascending, stabilization, and maturement. Maturity of construction industry is a term of broad sense of construction industry that is easily to figure current state of regional construction and shows what normal condition of construction is in regional economy.

• Journal of Korean Society of Rural Planning
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• v.16 no.3
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• pp.11-17
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• 2010

With international attention to the rural landscape, there have been landscape management and conservation efforts. Because it contains characteristics of rural area, rural landscape has been recognized as an important component of rurality. With rural amenity resources survey projects launched since 2005, rural landscape categorization and evaluation such as resource value, use value, beauty, originality, traditionality, maintenance are performed by expert questionnaire survey and 100 rural amenity resources are selected. In this study, we performed fractal analysis for developing evaluation system of the rural landscape photographs. In evaluating processes, main and surrounding landscape are separated and fractal indexes are calculated and analyzed with beauty value scoured by experts. Results show that beauty value is not significantly related with fractal index but differences of main and surrounding landscape fractal index.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.27-30
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• 2006

This study investigated influence of organic fiber type and contents on engineering properties of concrete. Test showed that increase of fiber contents decreased fluidity of fresh concrete and it was even worse in concrete adding cellulose fiber. It is decided that concrete containing more than proper level of fiber should be considered. In addition, concrete adding more fiber, nylon and cellulose, resulted in increase of air content but it was satisfied in aimed value. Bleeding capacity of concrete containing more fiber significantly declined and setting time of that was also slightly retarded. For the properties of strength, both compressive and tensile strength of fiber containing concrete were indicated at similar value to control concrete. However, it is clear that if those concrete containing fiber revised the value of increased air contents at fresh state, the strength value of that would be slightly increased.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.2242-2249
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• 2008

A severe problem in VE study of a project is to reduce value due to loss of performance, caused by focusing on cost reduction. Also a lack of understanding performance concept, no trial VE workshop as well as cost saving-based policy have not satisfied customer needs. A efficient VE job plan for especially large scale railroad construction project is proposed in this study. This study developed a more objective performance evaluation system for value engineering study of mega projects and suggested a systematic process of performance quantitative analysis for value improvement. The proposed performance measurement method would be very useful for better communication and consensus between decision makers and VE team.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.40-47
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• 2003

The main purpose of Construction Management(CM) is the improvement of efficiency and effectiveness of the project with construction methodologies systematically and technically. This pilot project Dong Myeong Service Area and Gas Station project among 5 projects designated and supervised by Ministry of Construction and transportation(MOCT), is to reduce cost, to maintain and control schedule, to keep proper quality, Claim and Risk through Partnering, Design Review, Constructability, Value Engineering and Project Management Information System(PMIS) and so on. Major factors of CM Plan are introduction of the phased and classified Construction Management Services from initiation of project to completion and adaptation of CM technologies and guide the implementation methodologies of the CM Pilot Project in CM construction market.