| Project/Area Number |
01550377
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
コンクリート工学・土木材料・施工
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| Research Institution | Kyushu Institute of Technology |
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Principal Investigator |
IDEMITSU Takashi Kyushu Institute of Technology, Civil, Mechanical and Control Engineering, Associate Professor, 工学部, 助教授 (30039078)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAYAMA Shunichi Kyushu Kyouritsu University, Civil Engineering, Associate Professor, 工学部, 助教授 (50039137)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1990: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Partially prestressed concrete / Reinforcing bar / Crack restraint / Precast member / Transfer bond / 伝達長 / ひびわれ / プレキャストコンクリ-ト / プレストレス |
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| Research Abstract |
When a precast RC member is fabricated in a factory, the cracks due to the impact load during transportation and the shrinkage of concrete occur very often. The authors tried to prevent the occurrence of these cracks by prestressing the reinforcing bars like PC tendons. From the results of some basic experiments, it has been made clear that by applying prestressing force in bars, not only the less cracking RC members but also the partially prestressed PC members can be obtained.
Further experiments were carried out and the following results were obtained :
(1)The partially prestressed PC members can be got by prestressing the bars up to a value larger than 60% of the yield point when SD30 is used
(2)Only about 30% of initial prestressing force remains in the bars after a few years, but it can considerably restrain the development of the crack width.
(3)The mechanism of transfer bond between reinforcing bars used as prestressing tendons and concrete at the end parts of precast members has been made clear and it's also confirmed that the prestressed bars can be anchored at the end parts, even the compressive strength is lower than 200 kgf/cm^2.
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