| Project/Area Number |
18H01520
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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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| Review Section |
Basic Section 22020:Structure engineering and earthquake engineering-related
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| Research Institution | Nagoya University |
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Principal Investigator |
Hanji Takeshi 名古屋大学, 工学研究科, 准教授 (80452209)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Project Status |
Completed (Fiscal Year 2020)
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| Budget Amount *help |
¥13,910,000 (Direct Cost: ¥10,700,000、Indirect Cost: ¥3,210,000)
Fiscal Year 2020: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2019: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2018: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
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| Keywords | 疲労き裂 / 維持管理手法 / 鋼橋 / き裂進展 / 残留応力再配分 / 橋梁システム / 疲労限界状態 / き裂進展性 / 面外ガセット溶接継手 / 残留応力 |
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| Outline of Final Research Achievements |
In order to maintain and manage existing steel bridges rationally and strategically, it is desirable to evaluate fatigue cracks generated in welded joints from the viewpoint of its propagation behavior. In this study, for evaluating fatigue crack growth occurring from welded joints in actual steel bridges, first, the re-distribution behavior of welding residual stress due to crack growth was examined by experiments and analysis. As a result, it was revealed that when a crack initiate and propagate from a weld toe, which is usually in a tensile residual stress field, the residual stress is re-distributed so that the tensile residual stress always acts near the tip of the crack. Based on the results, the growth of a fatigue crack from a web-gusset welded joint in a typical multiple girder bridge was simulated, and the load redistribution behavior due to the crack growth and the fatigue limit state for this type of crack were investigated.
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| Academic Significance and Societal Importance of the Research Achievements |
疲労き裂の進展やそれを起点としたぜい性破壊を評価する際には溶接残留応力の影響は無視できないが，本研究により得られたき裂進展に伴う残留応力の再配分挙動に関する知見は，構造物の疲労限界評価の精緻化につながるものである．
鋼橋に発生した疲労き裂に対して，その進展性に基づき部材や橋梁の健全性を評価する考え方は性能照査型のき裂管理といえ，橋梁管理者の人的・財政的資源が限られる中で，維持管理の合理化，持続可能な維持管理の実現に資するものであり，その社会的意義は大きい．
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