• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.75-77
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• 2013

In this study, the characteristics of temperature history was evaluated for three hot wires with different capacity installed in slab concrete which are relatively thin. Results can be summarized as follows. First, for the case of material using 5W hot wire, all decreased to below zero at or around 24 hours. Similarly, the material using 20W hot wire decreased to 2℃ below zero at or around 80 hours but satisfied the accumulative temperature of 45° D·D at 7 days of material age. On the other hand, the case of 30W hot wire, the biggest capacity, showed the high temperature history of 5℃ in average at all areas except the corners. Thus, the target accumulative temperature was secured at or around the 3 days of material age. Considering the above, the initial damage by freezing can be prevented only if 20W or higher hot wires are used for the slabs at -10℃ of extremely low temperature environment.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.631-636
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• 2002

It is common in multistory flat-plate structures that newly cast slabs are supported by a number of previously cast floors. Then the weight of newly cast slabs is imposed on shored previously cast floors as load, and this load may be large as double as dead load. Because early-age construction loads cause large immediate deflection and creep deflection with cracks, this loads influence long-term behavior of slabs. In current provision, the minimum thickness is required to satisfy serviceability But this minimum thickness based on historical precedent is determined by span length, therefore the minimum thickness of current provision can not includes properly the effect of construction scheme including the number of shored floors and construction cycle. In the present study, a minimum thickness criterion, which includes the effect of concrete strength, geometry of slabs and construction scheme, was developed from computer-based iteration using deflection calculation procedure of current code method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2002년도 학술논문발표회
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• pp.61-64
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• 2002

The present age, it takes an interest in maintenance and preserve of the aged constructive materials cause destruction of environmental reason and a loss of resource. As answering question given to candidates at a civil examination, it is carbonated concrete construction materials to give alkalization agent to seek the plan to be extended durable life. The representative material, it was known for a chemical compound of alkailzation-Silica acid with Lithium and also used on inside and outside the country. But, it is so difficult to decide the effect because the work is to be repeated for a processing of construction. So, in this study, to investigate recovery faculty on a period of incubation that restrain processing of carbonation by impregnation alkalization agent, we were made good progress from basic test through comparative and analysis at laboratory and the spot of construction.

• 한국안전학회지
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• 제19권4호
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• pp.161-165
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• 2004

철근콘크리트조 공사의 안전성과 효율성은 동바리-슬래브거푸집의 최적의 운영에 달려있다. 철근콘크리트공사에서의 사고는 주로 가설공사에 과도한 하중이 작용하였거나 동바리를 조기에 철거하기 때문에 발생한다. 콘크리트의 조기압축강도발현이 공사중구조체의 안전에 중요하다. 슬래브-동바리의 상호작용에 관한 연구는 주로 무량슬래브 구조에 대하여 이루어 졌다. 본 연구에서는 전단벽식 철근콘크리트조 아파트에서 슬래브와 동바리에서의 하중분포를 유한요소법을 이용하여 조사하였다.

• Steel and Composite Structures
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• 제6권2호
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• pp.123-138
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• 2006

This paper proposes a model for the analysis of the construction sequences of steel-concrete composite decks in which the slab is cast-in-situ for segments. The model accounts for early age shrinkage, such as thermal and endogenous shrinkage, drying shrinkage, tensile creep effects and the complex sequences of loading due to pouring of the different slab segments. The evolution of the structure is caught by suitably defining the constitutive relationships of the concrete and the steel reinforcements. The numerical solution is obtained by means of a step-by-step procedure and the finite element method. The proposed model is then applied to a composite deck in order to show its potential.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.563-564
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• 2009

Ultra-High Performance Concrete (UHPC) compared to normal concrete is exhibiting extremely high strength characteristics with compressive strength and tensile strength reaching 200MPa and 15MPa, respectively. The mechanical characteristics of UHPC can be thus exploited advantageously in the construction of structure through the reduction of the cross-sectional area and fabrication of slim and light-weight of the structural members. In the case where the structural member is made of UHPC, the occurrence of crack can be prevented by releasing the restraint provided by the form in due time. This research performs parametric study of the failure characteristics of concrete such as failure energy and softening curve suggested by the viscous crack model approximating the failure of concrete. The scope of this research contains the results of tests performed to investigate the strength of UHPC during early elapsed time.

• 한국산업융합학회 논문집
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• 제22권2호
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• pp.125-135
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• 2019

In recent years, the digital transformation age represented by the "Fourth Industrial Revolution", which is a universalization of digitalization across all industries, has become a reality. In the construction sector in 2018, the Ministry of Land, Infrastructure and Transport established the Smart Construction 2025 vision and established the 'Smart Construction Technology Roadmap' aiming to complete construction automation by 2030. Especially, in the construction stage, field monitoring technology using drones is needed to support construction equipment automation and on-site control, and a 3D geospatial information model can be utilized as a base tool for this. The purpose of this study is to investigate the factors affecting earthworks work in order to manage changes in site conditions and improve communication between managers and workers in the earthworks plan, which has a considerable part in terms of construction time and cost as a single type of work. Based on this, field management procedures and applications were developed.

• 교육시설
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• 제12권5호
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• pp.47-56
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• 2005

Reports on population movement(2000-2030) by the National Statistical Office show that the number of elementary school age population will be decreased by 1.4million from 2005 to 2020. It will effect both school size and the policies for school facilities, which have focused on downsizing class as the high standard of OECD nations. As the unfolding evidence is emerging that a number of schools and classes will be emptied out by 2030. This study aims at developing a model for evaluating the validity of school establishment, which would help more reasonable decision-making for new school construction and the class extension in the existing schools. It classifies two different ways in founding a new school - school establishment in a residential developing site and school establishment for solving a overcrowd class. It proposes the assesment items and the methods for evaluating its validity. In the end, it suggests an assesment model which the district educational offices can use in the course of planning the student accomodations to schools and making decisions for new school construction and the class extension in the existing schools. This study would be expected to help the reasonable expenditure for school facilities and to restrict overbuilding of surplus classes.

• 건축역사연구
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• 제5권2호
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• pp.9-24
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• 1996

Owing to the energitic studies of the leading shcolars, some paradigmatic theories on the history of Korean dwellings have been suggested. They constructed periodization of their own and defined characteristics of each period with very limited historical materials. However the new historical materials have been discovered in the neighboring academic fields, which require to review the existing theories. This study aims at restructuring periodization in the history of Korean dwellings during the age of The prehistory and The ancient Kingdomes. Through the study, the existing theories on the same period are revived and evaluated based on the new materials. I suggest a new theory on the periodization and the characteristics of each period: a. the paleolithic period(6,000,000 B.P.-10,000 B.P.) : natural shelter, the emergence of man-made dwellings b. the neolithic period(10,000 B.P.-1,000 B.C.) : construction of pit house c. the bronze period(1,000 B.C.- 300 B.C.) : construction of semi-pit house d. the early metalic period(300 B.C. - 300 AD.) : construction of house on the ground level development of the Ondol system e. the ancient kingdomes period(300 AD - 700 AD): classification of housing type

• 한국주거학회논문집
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• 제17권1호
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• pp.97-105
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• 2006

The purposes of this study are to find out the current status and features of earth housing, and to explore users' level of satisfaction and needs of improvement about earth housing. Primary findings are as follows: (1) The area of earth housing is generally 25-34 pyong and the construction cost of earth housing is usually 3,000,000-3,400,000 won per pyong. (2) The age of earth house users is generally forties, fifties, and sixties. And their occupation is usually retiree and farmer. The age of earth based pension users is generally twenties and thirties. (3) The construction method of earth housing is usually earth brick structure reinforced with wood structure and earth brick structure(adobe). (4) The finish of outer wall is generally earth brick laying and earth plaster. And the finish of inner wall is usually wall paper and earth plaster. Roof tile and asphalt shingle is frequently observed as roof finish. (5) Users' satisfaction about earth housing is investigated high level. Especially, the satisfaction degrees about faculty of humidity control, stink elimination, prevention from sick house syndrome, support for psychological stabilization and deep sleep are observed very highly. (6) Reduction of construction cost and prevention of crack is investigated as needs of improvement about earth housing.