2021 Fiscal Year Final Research Report
Welding Residual Stress and Fatigue Performance Improvement in Narrow Part between Vertical Stiffener and Longitudinal Rib of Steel Plate Deck
| Project/Area Number |
19K04577
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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 22020:Structure engineering and earthquake engineering-related
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 溶接 / 残留応力 / 疲労 / 局所加熱 |
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| Outline of Final Research Achievements |
The purpose of this study is to clarify the characteristics of welding residual stress and to improve fatigue resistance of steel bridge decks in which fatigue cracks are prone to occur, especially in the region between vertical stiffeners and longitudinal ribs at the edge of narrow slabs. Thermal elastic-plastic analysis was performed on a small specimen modeling the target structure to confirm that local heating reduces welding residual stresses. Fatigue tests were performed on the specimens as welded and with local heating. As a result, the fatigue life of the locally heated specimen tended to be significantly longer than that of the as-welded specimen. It was found that the effect of fatigue life improvement was strongly influenced by the condition of cyclic external loads.
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| Free Research Field |
構造工学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究成果により，局所加熱による溶接残留応力の低減が道路橋鋼床版の端部垂直補剛材とデッキプレートのまわし溶接部に適用可能であることが明確になった．また，局所加熱による残留応力の低減が疲労寿命の向上効果にどのように寄与するのかを明らかにしたことは学術的に大きな意義を有する．また，既存の疲労寿命向上技術と，本研究で注目した局所加熱の疲労寿命向上効果を比較することで，その位置づけを明確にしたことは，実用化に対する具体的な知見を示したものであり，その社会的意義は大きいと言える．
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