2022 Fiscal Year Final Research Report
Evaluation of residual load carrying capacity of pre-tensioned prestressed concrete girders after a fire considering the effect of explosion of concrete cover
| Project/Area Number |
20K04651
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 22010:Civil engineering material, execution and construction management-related
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| Research Institution | Osaka Institute of Technology |
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Principal Investigator |
Inoue Susumu 大阪工業大学, 工学部, 教授 (30168447)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | プレテンションPC桁 / 火災 / 耐荷力 / 爆裂 / PC鋼材 / 最高受熱温度 |
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| Outline of Final Research Achievements |
Unless the maximum temperature of prestressing steels reaches 400℃, which is a guideline for reducing the residual strength after cooling, and the explosion of concrete does not reach the prestressing steels, the load carrying capacity of the member will not be significantly reduced under a normal external fire. On the other hand, it is necessary to appropriately evaluate the decrease in steel strength in situations where the remaining cover is less than 20 mm after being subjected to a hydro-carbon fire with temperatures exceeding 900℃.
In this study, the relationship between the residual cover after explosion and the maximum temperature of the prestressing steels, and the relationship between the maximum temperature and the residual strength of the prestressing steels are obtained. If the maximum temperature of prestressing steels can be obtained analytically, the results of this research could be used to evaluate the residual load carrying capacity of PC girders after fire damage.
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| Free Research Field |
コンクリート工学
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| Academic Significance and Societal Importance of the Research Achievements |
火災被災後のプレテンションPC橋の的確な健全性評価に際しては，爆裂の影響（深さ・範囲等）を考慮することが重要である。本研究では，爆裂後の残存かぶりとPC鋼材の最高受熱温度の関係，PC鋼材の最高受熱温度と残存強度の関係を示すことができた。これにより，火災の種類と被災後の残存かぶりからある程度の残存耐荷力評価が可能となるとともに，爆裂を考慮した熱伝導解析等によりPC鋼材の最高受熱温度を計算で求めることできれば，本研究成果を用いてより精緻な評価が可能となる点に学術的・社会的意義が存在すると考えている。
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