• Title, Summary, Keyword: 매트기초

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Analysis of the Effect of Solar Radiation on Internal Temperature Distribution in Concrete Mat Foundation (태양 복사열이 콘크리트 매트기초의 내부 온도분포에 미치는 영향에 관한 해석적 연구)

  • Song, Chung Hyun;Lee, Chang Joo
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.1
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    • pp.63-72
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    • 2017
  • This research investigated the effect of solar radiation on the temperature distribution in concrete mat foundation. Zhang and Huang Model was utilized to estimate solar radiation heat at a given date and time. A one-dimensional finite element formula was derived with the fundamental laws of heat transfer and Galerkin method. Based on the formula, a one dimensional finite element analysis code was developed using MATLAB. Hydration heat analysis of mat foundation were conducted using the developed code. It was found that the solar radiation reduced the maximum temperature difference in mat foundation, and this temperature difference reduction was more prominent in case of summer season cast, a higher initial concrete temperature, and a thicker mat foundation depth. The research recommended that the solar radiation should be considered in hydration heat analysis of concrete mat foundation so as not to overestimate the maximum temperature difference in mat foundation.

Curing Method Designation System in Mat Foundation Construction (매트기초 건설을 위한 양생방법 선정시스템)

  • Lee, Tae-Gyu
    • The Journal of the Korea Contents Association
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    • v.12 no.8
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    • pp.366-372
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    • 2012
  • In most of construction work, especially mat foundation construction, it is very important that accidents be prevented at early aged construction stage. To reduce the risk of accidents, it is necessary to choose the curing method to provide instructions for safety forming work by proper curing of concrete after placing. Therefore, this paper has proposed a designation algorithm of curing method for representing curing type and period by analyzing the transient hydration heat solution, focusing on mat foundation construction. This has been implemented, moreover, using an object oriented programming language to develop structural analysis system taking account crack index. In addition, we present in this paper a safety curing management system developed to assess risk during forming work.

Case Study on Mega Foundations of Domestic and Foreign Super High-Rise Buildings (국내외 초고층 건축물의 대단면 매트기초 시공사례와 분석)

  • Park, Young-Seok;Lee, Hai-Chool;Kim, Kyoung-Min;Cho, Chang-Shik;Rhim, Hong-Chul
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.17-19
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    • 2010
  • This paper describes the possibility of the raft thickness reduction for mega foundations system of super high-rise buildings through a case study on domestic and foreign super high-rise buildings. In case of super high-rise buildings, the size of foundations, especially raft becomes wider and deeper because of heavy upper load. It is difficult to pour concrete of this kind of mega foundation, and cracks by hydration heat could happen. Therefore, there are several ways to reduce the raft thickness of mega foundations. Piled-raft could be the one because moment and shear load that the raft subjects on by soil reaction are lower. The effect of the piled-raft foundation on the raft thickness reduction could be confirmed by comparison of super high-rise buildings with pile, piled-raft and mat foundation. Furthermore, it was showed that the raft thickness could be more reduced by locating piles right under the vertical members of super structures.

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A Study on the Effect of the Construction Conditions on a Thermal Crack of Mat Foundation (매트기초의 온도균열에 미치는 시공조건의 영향에 관한 연구)

  • 이도범;김효락;최일호
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.1-4
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    • 2003
  • Recently, a structure has been larger and higher under the improvement of construction technique. So, a mass concrete constructions that a mat foundation thickness of structure is over 80cm have been many. Also, because of the reason of high strength of concrete, the matter of thermal crack have become an important task to be solved absolutely. tn a cause of a thermal crack occurrence, there are material used, mixture of concrete, construction condition and so forth. In this study, we executed temperature and stress analysis of mat foundation to know the effect of the construction condition on a thermal crack of mat foundation. And we evaluated quantitatively about the occurrence possibility of thermal crack using the hydration heat analysis program. By using of this analysis technique, we will can control skilfully the quality of a mat foundation in advance.

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A Method on the Control of Hydration Heat of Mass Concrete Considering Difference of Setting Time (응결 시간차를 활용한 매스 콘크리트의 수화열 조정 공법)

  • 심보길;윤치환;오선교;최주석;한천구
    • Magazine of the Korea Concrete Institute
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    • v.14 no.1
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    • pp.49-52
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    • 2002
  • 종전의 경우 건축물의 기초 구조는 직접 기초 및 말뚝 기초 등이 많이 활용되었으나 최근에는 말뚝 기초의 경우 소음, 진동 등의 환경 문제가 중요시됨에 따라 대부분 매트 기초로 시공하는 경우가 많아졌다. 따라서, 기초 부분의 매트 콘크리트 시공은 환경 문제를 해결하고 건물의 하부구조를 안전하게 지탱하게 하는 역할은 만족되었지만. 두께가 80cm를 넘어 매스 콘크리트로 되는 경우가 많아 수화열에 의한 균열 문제 등은 콘크리트의 품질 확보에 있어 새롭게 해결해야만 하는 중요한 과제로 등장하고 있다.(중략)

A Fundamental Test of Temperature Crack Reduction Method Application by Setting Time Control of Large-Scaled Mat Foundation Mass Concrete (초대형 매트기초 매스 콘크리트의 응결시간조정에 의한 온도균열저감 공법적용의 기초적 실험)

  • Han, Cheon-Goo;Lee, Jae-Sam;Noh, Sang-Kyun
    • Journal of the Korea Institute of Building Construction
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    • v.9 no.3
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    • pp.95-101
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    • 2009
  • Constructing large-scale mat foundation mass concrete is increasing for the stability of building structure, because a lot of high rise building are being built in order to make full use of limited space. However, It is of increasing concerns that because limited placing equipments, available job-site and systems for mass concete placement in construction field do not allow to place great quantity of concrete at the same time in large scale mat foundation, consistency between placement lift can not be secured. And also, it is likely to crack due to stress caused by the difference of hydration heat generation time. To find out the solution against above problems, this study is to reconfirm the performance of normal concrete designed by mix proportion and super retarding concrete. The Fundamental test shows what happens if low heat proportioning and control method of setting time are applied at the job-site of newly constructed high rise building. The test result show that slump flow of concrete has been somewhat increased as the target retarding time gets longer, while the air content has been slightly decreased but this is no great difference from normal concrete. The setting time shows to be retarded as target retarding time gets longer, the range of retarding time increases. It is necessary to increase the amount of mix of super retarding agent in the proportion ration by setting curing temperature high since outdoor curing is about 6 hours faster than standard curing, which means the temperature of the concrete will be higher than the temperature of the surrounding environment, due to its high hydration heat when applying in a construction site. The compressive strength of super retarding concrete appears to be lower than normal concrete due to the retarding action in the early stage. However, as the time goes by, the compressive strength gets higher, and by the 28th day the strength becomes the same or higher than normal concrete.