| Project/Area Number |
03555105
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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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 | UTSUNOMIYA UNIVERSITY |
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Principal Investigator |
SATO Ryoichi UTSUNOMIYA UNIVERSITY,FACULTY OF ENGINEERING,ASSOCIATE PROFESSOR, 工学部, 助教授 (20016702)
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| Co-Investigator(Kenkyū-buntansha) |
SOGO Shigeyuki OHBAYASHI CORPORATION,TECHNICAL RESEARCH INSTITUTE,CHIEF RESEARCHER, 技術研究所, 主任研究員
UJIKE Isao UTSUNOMIYA UNIVERSITY,FACULTY OF ENGINEERING,RESEARCH ASSOCIATE, 工学部, 助手 (90143669)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1992: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1991: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | THERMAL STRESS / FREE FLEXURAL DEFORMATION / RESTRAINING MOMENT / CRACK WIDTH / REINFORCEMENT STRESS / FLEXURAL CAPACITY / DESIGN METHOD / 鉄筋コンクリ-ト / 温度ひびわれ / たわみ / 鉄筋ひずみ |
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| Research Abstract |
In order to help establish design method of reinforced concrete structure subjected to external load combined with thermal stress due to hydration heat of cement, investigations were performed experimentally and unmerically on thermal stress and flexural deformation of concrete beams constructed in two stages. Furthermore, the effect of thermal stress on reinforcement stress, crack width and yielding moment of the beams were investigated, which were restrained flexurally and perfectly, and thereafter loaded.
(1) The average curvatures at peak temperature and at stabilized temperature depend on rigidity of the first stage concrete. All three creep models (CEB/MC 90, JSCE,Iwaki et al) did not predict the average curvatures both at peak and at room temperature with satisfactory accuracy.
(2) Temperature change in young concrete block produced higher reinforcement stress and wider crack width in serviceability state than those in the companion beams cured in room temperature when residual flexural deformation was restrained perfectly, which were underestimated by conventional method.
(3) Larger existing block did not necessarily cause higher reinforcement stress as well as wider crack width due to temperature change than smaller one because residual flexural deformation of the beam with smaller existing block is considerably larger than that with larger one.
From the results the necessity considering the effects of thermal stress in serviceability limit state design for concrete members made in two stages were shown. The effects are estimated based on free flexural deformation, degree of restraint and flexural rigidity considering cracks of reinforced concrete members.
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