2007 Fiscal Year Final Research Report Summary
Evaluation on spatial variability of corrison of steel bar in marine concrete structure
| Project/Area Number |
18360221
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural engineering/Earthquake engineering/Maintenance management engineering
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| Research Institution | Independent Administrative Institution Port and Airport Research Institute |
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Principal Investigator |
YOKOTA Hiroshi Independent Administrative Institution Port and Airport Research Institute, LCM Research Center, Director (50344312)
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| Co-Investigator(Kenkyū-buntansha) |
IWANAMI Mitsuyasu Independent Administrative Institution, Port and Airport Research Institute, Geotechnical and Structural Engineering Department, Senior Researcher (90359232)
KATO Ema Independent Administrative Institution, Port and Airport Research Institute, LCM Research Center, Senior Researcher (90371765)
SHIMOMURA Takumi Nagaoka University of Technology, Faculty of Engineering, Associate Professor (40242002)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Concrete / Corrosion of steel bar / Localization / Anisotropy / Marine structure / Structural performance / Acceleration of corrosion / Cross-sectional loss of steel bar |
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| Research Abstract |
Corrosion of steel reinforcement embedded in concrete has a great influence on structural performance and durability of reinforced concrete(RC) structures. However, the relationship between the degree of steel reinforcement corrosion and structural performance has not been made clear adequately because of wide variations in corrosion within a structural member and anisotropy within a structure.
In this study, through measurement of the cross-sectional areas of corroded steel bars taken from real structures, variations in corrosion of steel reinforcement were quantitatively made clear. Moreover, an influence of the variation of corrosion on mechanical properties of RC structures was experimentally investigated by reproducing various variations of steel reinforcement corrosion.
As a result, it was made clear that strengths of corroded steel reinforcement are estimated by using the maximum cross-sectional loss. Regarding the structural performance, the first yield load was accurately evaluated by using the maximum loss in cross-sectional area of steel reinforcement, but it was not greatly influenced by the spatial variation of corrosion. After the first yield, an influence of localized corrosion of steel bars on structural performance was varied depending on the diameter and number of steel reinforcement and position of corrosion. In particular, the load-carrying capacity of RC member was influenced by the mechanism of bond stress transfer between corroded steel reinforcement and concrete at the corroded position. Therefore, it was not possible to estimate the structural performance by the maximum loss in cross-sectional area of steel bar.
Based on these results obtained in this study, finally, the concept of simplified assessment was proposed regarding the structural capacity of deteriorated RC members and structures. The life-cycle management system was developed taking into account the variations in corrosion of steel bars in RC structures.
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