• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.891-892
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• 2005

• Journal of the Korea Institute of Building Construction
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• v.14 no.2
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• pp.118-126
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• 2014

The establishment of the technology for evaluating friction resistance and pipe pressure and the relation of the fluid characteristics and pumpability of concrete is essential for concrete pumping performance for the rapid construction of super-tall buildings. In this study, a quantitative evaluation of concrete fluid characteristics and surface friction resistance was performed, applying different concrete mix proportions and pumping conditions. To achieve this, we developed a temporary horizontal pumping evaluation system to measure pipe pressure and surface friction characteristics, and performed an experiment to investigate the relations between concrete rheology characteristics and friction resistance in pipe. The experiment found that in terms of the rheology characteristics, plastic viscosity was reduced remarkably after pumping. As well, high regression between the surface friction and pressure gradient was confirmed. This means that it is possible to evaluate the friction resistance between concrete and pipe by means of a pumping system that includes a frictional resistance testing pipe. In addition, high regression between the plastic viscosity of concrete after pumping and friction resistance coefficient was confirmed. Finally, it is considered that pumping pressure can be predicted using the friction resistance coefficient derived in this study, and it has high regression.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.89-100
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• 2022

The development of the Construction Production Rates System for appropriate construction cost calculation has recently come to the fore as a means of invigorating OSC based PC structure which currently needs institutional frameworks. PC structure based construction expenses consist of the factory-built assembly, transportation and on-site installation. Recently, in the field of transportation and site installation, research on product structure development is being conducted, such as presenting the standard product calculation system reflecting the results of field survey for each subsidiary materials (Lee et al., 2021). On the other hand, there is no ongoing research on estimating construction expenses of Factory-built assembly. This study suggests Construction Production Rates System which can be used for PC subsidiary materials based Factory-built assembly cost estimations. For the research, work types for the construction procedures have been categorized, and the standard input manpower suitable for the corresponding work characteristics has been derived from analyzing the associated Construction Standard Production Rates for each work type. Also, as the research referred PC subsidiary materials (such as columns, beams, walls, and slab, as well as on-site installation) and the standard number of workforce based on work types, one can calculate direct labor cost, using what the research shows. In addition, it suggests that the size of individual subsidiary materials be the extra cost factor, by using the characteristics that productivity changes depending on the size(m³) of subsidiary materials. It is expected that the research can contribute to objectively verifying factory-built assembly cost through of PC structure, which currently relies on estimates.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.143-150
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• 2009

The bar-shaped electrode is very popular in earth construction for its easy obtainments of the regulative grounding resistance values on power distribution systems in many countries. For these reason, a lots of researches are being proceeded on its deformation and materials. But the grounding construction has limit for improvement the grounding resistance characteristics not only by the improvement of the driven electrode, because that the grounding characteristics are very sensitive to soils(hard, soft). This study is about the construction methods on which the driven electrode can be serially or parallely connected using by hollow screw rod for obtaining the regulative grounding resistance values. The experimental results show that the grounding resistance values are reduced more than 30[%] comparing with the other construction methods under the same conditions(earth resistance, numbers of driven electrode, construction method of serial and parallel, chemicals for reducing grounding resistance, water).

• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.24-34
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• 2010

Benchmarking is an effective tool supporting improvement of corporate competitiveness and development of management strategy, however, its effectiveness may be compromised if its target and approach are not appropriate. Notably, the construction industry of Korea is unique in that it has a number of competitors sharing the same category and is significantly exposed to changes in external environment in terms of legal, regulatory and policy frameworks. Such characteristics make target corporate category rather than single company more suitable as benchmarking target and necessitate analysis of external environment. This study intends to analyze the characteristics of construction industry in Korea and conditions of domestic companies in order to propose a benchmarking process for construction industry differentiated from conventional ones.학교 건축공학과, 산학협력기술연구원;경희대학교 대학원;경희대학교 대학원;

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.553-557
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• 2007

In general, material cost of a construction project is more than 30$^{\sim}$40% of total construction cost, thus on site material control is very important. The factthat buildings have recently become higher and bigger also increases the importance of on site material control. However, on site material control has not been considered as an important management issue. This study classifies building construction materials considering the material delivery characteristics such as ETO, ATO, MTO and MTS and the unique characteristics of each materials. Using the classification, this study examine the requirements for on site material control of each materials. Finally, this study suggests on site material control systems for each construction material.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.257-262
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• 2003

This study is aimed to research the management methodology for the process of GIS database construction. In general, used methodologies are made for the purpose of application program development. And the methodologies reflected GIS characteristics are also applied for GIS software development. But the software methodologies are never introduced to construction of GIS database. In this study, various common methodologies are investigated and analyzed, and the methodology which include the characteristic of GIS database construction process as work steps and detail paths is developed and suggested.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.121-128
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• 1991

The changes of stuctural systems in constructing prestressed concrete bridges are investigated according to several construction methods. Based on these investigation, structurally meaningful works are summarized and defined as "Construction Commands". And time-dependent characteristics of concrete and prestressing steels are fully considered. For the static and/or dynamic analysis of three dimensional prestressed concrete bridges at ant construction stages, it is propoesd to use "Comstruction Commands" directly as user's input data. A example of cable syayed bridges is presented by the computer program developed by the present simulation method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.5
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• pp.601-608
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• 2021

Recently, despite a decrease in the number of working days and an increase in the number of non-working days due to an increase in the abnormal climate and the revision of the Labor Standards Act, a standard construction period reflecting this has not been established. For this reason, even if the appropriate construction period is calculated at the site, there is a situation where delays occur due to unexpected circumstances. Therefore, this study proposes a method of calculating the number of non-working days for railway bridgework construction that reflects changes in construction conditions and climate change and reflects this to railway bridgework construction, and the number of working days was calculated. As a result, the number of non-working days by region and month in Korea was derived, and through this, the necessity of regulations and standards for appropriate construction periods reflecting regional characteristics and characteristics of each construction type was presented.

• Journal of the Korea Institute of Building Construction
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• v.4 no.4
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• pp.103-108
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• 2004

In order for concrete as a basic material constituting reinforced concrete structure to meet the required performance, it is necessary to satisfy various requirements in concrete construction. Among them, form work has significant effects not only on the process of molding fresh concrete but also on the quality and performance of hardened concrete. Recently, the decrease and aging of form workers is becoming a great problem in the construction industry and, as a result, it is required to rationalize form works and reduce labor costs for employing form workers. Because form construction methods decide the type of form according to required performance, it is necessary to develop various form construction methods and examine their performance. Thus the present study purposed to expand the scope of application of form construction methods and, for this purpose, investigated the basic characteristics of rib- lath form and presented a system form construction method.