• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.753-756
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• 2008

Recently, construction work period reduction is a very important topic of construction business circles. Because that is just big cost reduction. There is an important part of construction to decide the removal time of form. For prediction strength for removal form, P type schmidt hammer method and maturity method is used that. In case early strength prediction of maturity method, that is problem. Because setting duration of concrete is not proper considering. So this experimental study is a coefficient(A) of maturity method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.23-26
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• 2006

The study about the concrete to use recently a light weight aggregate, processed actively. And concrete pumping with a high pressure pump has been popularized, the mechanical development, such as high pressure pumps or pipes, is progressing rapidly. Concrete placing by pumping has the advantage of the reduction of the construction period with workability, easiness of work and the increase of placing, but the quality variation of concrete is caused by pumping is seldom considered, including the increase of the pipe length by high-rising and large-sizing, there by the loss of the unit quantity of water, with pumpability or workability deteriorated. In this research, we will compare and analyze before pumping and after pumping samples of ready-mixed light weight concrete. The result of study as follow. The case of a light weight concrete which the low slump is more decrement compared with high slump light weight concrete in after pumping samples. After pumping the water by pressure of a pump was absorbed to the aggregate inside, and it showed an increase of compression strength about $5{\sim}20%$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.42-43
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• 2019

In-situ production of PC (precast concrete) members can reduce costs by about 14.5% -21.6% compared to in-plant production due to the reduction of transportation costs, factory profits and overhead costs. However, in-situ production of PC members presents a variety of risks, including member production and yard area securing, and lead time for production within the installation period. To solve this, it is necessary be able to analyze and control and monitor the risk factors that influence in-situ production for PC member. The purpose of this study is to develop a dynamic simulation model for in-situ production and erection integrated management for PC members. For this study, risk factor identification, causal loop diagram, and dynamic simulation model construction were performed sequentially. The results of this study will be used as a basis for developing a risk management model for PC in-situ production.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.535-542
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• 2010

Various difficulties have been increased in the construction of public structure; like the road in the overcrowding urban area, because of civil complaint, cost and period of construction. In oder to overcome these social problems, the tunnel has been planned the road design. Despite the resolution, there are many technical problems when constructed near facilities. The design of new tunnel below the existing service reservoir is applied to the ambient vibration blasting using Plasma. The result of test blasting was exceeded the standard ("2kine"). So it was considered a countermeasure for the vibration reduction applied to change the controlled blasting method, reduce the charge, add the pre middle horizontal hole in the cut blasting site, and so on. The result was satisfied the standard. Accordingly, if the quality of blasting process can be managed well, the application of this alternative method is highly effective one. Also, based on cost analysis between two methods, the alternative method is very competitive.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.44 no.3
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• pp.10-21
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• 2021

Recently, the demand for atypical structures with functions and sculptural beauty is increasing in the construction industry. Existing mold-based structure production methods have many advantages, but building complex atypical structures represents limitations due to the cost and technical characteristics. Production methods using molding are suitable for mass production systems, but production cost, construction period, construction cost, and environmental pollution can occur in small quantity batch production. The recent trend in the construction industry calls for new construction methods of customized small quantity batch production methods that can produce various types of sophisticated structures. In addition to the economic effects of developing related technologies of 3D Concrete Printers (3DCP), it can enhance national image through the image of future technology, the international status of the construction civil engineering industry, self-reliance, and technology export. Until now, 3DCP technology has been carried out in producing and utilizing residential houses, structures, etc., on land or manufacturing on land and installing them underwater. The final purpose of this research project is to produce marine structures by directly printing various marine structures underwater with 3DCP equipment. Compared to current underwater structure construction techniques, constructing structures directly underwater using 3DCP equipment has the following advantages: 1) cost reduction effects: 2) reduction of construct time, 3) ease of manufacturing amorphous underwater structures, 4) disaster prevention effects. The core element technology of the 3DCP equipment is to extrude the transferred composite materials at a constant quantitative speed and control the printing flow of the materials smoothly while printing the output. In this study, the extruding module of the 3DCP equipment operates underwater while developing an extruding module that can control the printing flow of the material while extruding it at a constant quantitative speed and minimizing the external force that can occur during underwater printing. The research on the development of 3DCP equipment for printing concrete structures underwater and the preliminary experiment of printing concrete structures using high viscosity low-flow concrete composite materials is explained.

• Korean Institute of Interior Design Journal
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• v.25 no.1
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• pp.93-100
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• 2016

Long-life housing means a housing which structural members (Support) such as columns and floor are maintained for a long period of time and the housing can be used for approximately 100 years by replacing components (Infill) such as walls and furniture. The government established "Certification standards of long-life housing construction" on December 24, 2014, requiring the long-life housing certification for construction of apartment houses for over 1,000 households. However, it is necessary to prepare an incentive measure which could be granted to construction related personnel and housing owners due to the effectiveness of such system and recognition that the initial construction cost of long-life housing is high. The purpose of this study is as follows. First, the reasons and necessity of long-life housing cost increase for each construction company, housing owner, infill component manufacturer and designer which are long-life housing related personnel are determined. The direction of incentive grant for supplying long-life housing based on the determined items is established. The result of this study is as follows. First, a special treatment which is higher than the alleviation of construction standards according to the previous ordinance is necessary for construction companies to secure the business feasibility. Also, incentives such as the provision of service space and wide balcony are necessary to improve the preference level of parceling out. Second, financial incentives such as financial support for housing purchase, reduction and exemption of tax (acquisition tax and registration tax), and support of maintenance cost are required for house owners. Third, it is essential to increase opportunities to participate in the market for infill component manufacturers by applying additional points for PQ. Fourth, it is needed to provide compensation for additional human resource and time at the time of designing to designers by preparing the long-life housing design cost standards.

• Korean Journal of Construction Engineering and Management
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• v.11 no.2
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• pp.116-123
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• 2010

Since the Enforcement Decree of the Housing Act was changed in 2007, remodeling demands have increased. For this reason, many research studies are actively discussed for vitalizing remodeling, but countermeasure plan for generated construction waste is not enough. This study aims to provide basic data for the reduction plan of construction waste caused by the remodeling project through the investigation of apartments residents' priorities about remodeling elements for reducing construction waste. In this study, remodeling elements have been drawn through the literature investigation. As a result, subordinates were classified into 21 elements and superordinate were classified into 6 elements. Expert interviews were conducted to check the reliability about subordinate and superordinate elements of remodeling and the questionnaire survey were conducted to determine the residents preference of apartments remodeling elements. As a result of the questionnaire survey, we found out the characteristic of preference for apartments remodeling elements such as the period of apartment, the location and the financial condition respectively. This study presents a basic data for considering the remodeling as well as the apartment plans for the resident's preference. Further, many studies about the reduction plan of construction waste caused by the remodeling project will have to be discussed.

• Korean Journal of Construction Engineering and Management
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• v.16 no.6
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• pp.3-11
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• 2015

The current real estate market is in a state that is considerably shrink due to the recession and long-term reduction of trading. In response, the government recently announced an innovative way for the middle-class residential housing and it is taking the lead to activate the real estate market. Meanwhile, the domestic housing market is entering a transition period, including structural changes of household structure, changes from joeonse to rent increasingly. Also single-member households will rise steeply, so that makes the high demand of small houses. In addition, the domestic construction industry is interested in new technology called Modular building. The Modular construction is an off-site construction system that shorten construction period, eco-friendly building technology and mobility etc, which can be used in various field. Overall, there are two major issues of the current market, one is the change of the real estate market, and the other is the modular construction. This study will propose modular business model in the rental market through the analysis the profitability of the modular business scenarios and IRR analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.4
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• pp.705-713
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• 2016

For the soft ground construction, the factors not considered in the design stage occurs in the construction stage so that they cause the increase of the construction cost due to the structural stability and the design change. The subject of the study is the construction section of the industrial complex access road made in the Ochang region of Chungcheongbuk-do. The study is concerned with selecting the soft ground handling method such as the replacement method using rock debris and the surcharge reflecting the service load as the soft ground handling measure and analyzing the effect of reducing the construction cost with the stability of structures and the reduction of the construction period. The soft ground in the study section consists of sandy and cohesive soil and is 2.4m to 5.5m deep. It is distributed unevenly between the 1.5m to 5.9m stratums under the ground surface. Settlement is not serious, but the future uneven settlement and difference are expected so that the future settlement behavior is estimated by analyzing the site measurement results after the soft ground treatment. Moreover, in consideration of the regional characteristics and economic efficiency, soil with good quality is replaced with rock debris as the replacement material so that 29% of the construction cost is reduced due to the increase of stability and the reduction of duration. If the estimation of the dispersion of the pore water pressure within the dam body and the change of the underground water level and the relation of the actually measured soft ground with consolidation is studied further on the basis of the study, it is expected that the behavior of the soft ground will be correctly estimated in various site conditions.

• Journal of the Society of Disaster Information
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• v.18 no.4
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• pp.828-838
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• 2022

Purpose: Through the establishment of a computerized system of risk assessment, the purpose is to analyze the case of whether the co-workers who are subject to the risk assessment at the construction site can easily fill it out and expect disaster reduction through efficient risk assessment activities. Method: By providing the risk factors and safety measures for the work by selecting the type of work, the risk estimation and the establishment of countermeasures can be made, and a system has been established to enable practical disaster prevention activities by presenting disaster cases for the work. Result: Through the analysis of the change in the scaled disaster rate for the years following the on-site application after the establishment of the risk assessment computer system of H Construction Company, it was confirmed that the scaled disaster rate of the domestic construction industry increased, while the conversion disaster rate of H Construction Company decreased. Conclusion: Through the computational systemization of risk assessments, workers in the field can easily access the risk assessment, evaluate the risk factors of the process and establish risk prevention measures, and it has been analyzed that there is an impact on the reduction of the disaster rate during the operational analysis period.