| Project/Area Number |
05650432
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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 |
土木材料・力学一般
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| Research Institution | Gifu University |
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Principal Investigator |
ROKUGO Keitetsu Gifu University, Faculty of Engineering, Professor, 工学部, 教授 (40127155)
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| Co-Investigator(Kenkyū-buntansha) |
KURIHARA Norihiko Gifu University, Faculty of Engineering, Assistant, 工学部, 助手 (50262746)
UCHIDA Yuichi Gifu University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (20213449)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1993: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Concrete / Size-Dependent Properties / Size Effect / Strength / Deformation / Fractal |
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| Research Abstract |
The load carrying capacity of concrete members is not always proportional to their size. The load normalized with the size (for example, the strength expressed with the force per unit area) as well as the deformation normalized with the size often tend to decrease with the size. In this investigation, the size effects on strength and deformation of concrete and reiforced concrete members are investigated and the mechanism of size effects is discussed through experiments and numerical analyzes.
1. The relationship between the failure behavior of the portion (element) and that of the whole (system) is investigated. The following mechanisms of the size effect on strength are derived :
-Weaker portions, which tend to appear in the system of a larger number of elements, decreases the strength.
-Unevenness of deformation in the layr of the system decreases the strength.
2. In case of singly reinforced beams, the deformation capacity decreases with the increase in the effective depth and hence the size effect is recognized. the localization of the curvature becomes remarkable after the peak load.
3. It is shown that the tension softening diagrams are effective to deal with the flexural failure behavior of various kinds of concrete. The testing method to determine tension softening diagrams is proposed.
4) It is pointed out that the size effect on the shear strength of RC beams without web reinforcement is remarkable when super-high strength concrete is used.
5. The strain distribution due to micro-cracks is measured on tension surface of concrete beams in bending.The shape of strain distributions highly depends on the gauge length. This phenomena can be well explained through the fractal approach.
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