Improvement of fatigue strength in welded joints by externally bonded carbon fiber sheets using VaRTM technique

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06538
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Structural engineering/Earthquake engineering/Maintenance management engineering
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: Nakamura Hitoshi 首都大学東京, 都市環境科学研究科, 准教授 (70264596)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 構造工学・地震工学 / 構造・機能材料 / 維持管理工学 / 補修・補強 / 疲労対策 / CFRP / 溶接継手 / 疲労強度

Outline of Final Research Achievements

Fatigue damages have been frequently reported on urban steel bridges and their countermeasures are urgently required. As a preventive maintenance against fatigue damage, this study proposes a new repair method using externally bonded carbon fiber sheets using by the vacuum assisted resin transfer molding before initiation of fatigue cracks, and the validity and usefulness have been verified by experiments and analysis. Finally, for practical use to existing steel bridges, the strengthening design method using externally bonded CFRP will be established.

Free Research Field

土木工学

Academic Significance and Societal Importance of the Research Achievements

提案工法は，接着接合を基本としているため，当て板のボルト接合や溶接接合と比べて，母材への孔明けによる欠損や残留応力が生じないこと，母材への影響が極めて小さいことから，疲労対策としては有利であり，本研究の成果から補強効果が示されたため，溶接接合部の種々のディテールへの応用も十分に期待できる．