2020 Fiscal Year Final Research Report

Development of diagnosis method of load capacity of high strength bolted joint structure with corrosion and high endurance corrosion prevention technology

Research Project

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Project/Area Number	18H01525
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 22020:Structure engineering and earthquake engineering-related
Research Institution	University of the Ryukyus
Principal Investigator	SHIMOZATO TETSUHIRO 琉球大学, 工学部, 教授 (90452961)
Co-Investigator(Kenkyū-buntansha)	田井政行琉球大学, 工学部, 助教 (70646596) 押川渡琉球大学, 工学部, 教授 (80224228) 有住康則琉球大学, 工学部, 教授 (90109306)
Project Period (FY)	2018-04-01 – 2021-03-31
Keywords	腐食 / 高力ボルト継手構造 / 高力ボルト軸力 / 連結板耐力 / 耐力診断 / 防食 / 低温低圧型金属溶射
Outline of Final Research Achievements	The purpose of this study is to construct a strength diagnosis method for corroded high-strength bolt joint structures and to develop highly durable anticorrosion repair technology. Corrosion analysis between the corroded thinning shape and the residual axial force was performed, and a method for evaluating the residual axial force was derived. In addition, the effect of the corrosive shape peculiar to the connecting plate, which is severely corroded and thinned around the high-strength bolt, on the residual yield strength of the joint structure was evaluated. Based on the above results, a diagnostic method for corroded high-strength bolt joint structures was constructed. Furthermore, we verified the Cold Spray technology, which is a new anticorrosion technology using a mixed powder of alumina, which has a rust removing effect, and zinc, which has a sacrificial anticorrosion effect, in various experiments, and developed a practical and highly durable anticorrosion repair technology.
Free Research Field	鋼構造工学、橋梁工学、維持管理工学、腐食防食学
Academic Significance and Societal Importance of the Research Achievements	本研究では、腐食した高力ボルト継手構造の実用的な耐力診断法の構築および腐食した高力ボルト継手構造の高耐久性の防食補修技術の開発を目的として、耐力診断と防食補修技術の両方の成果を達成し、腐食した高力ボルト継手構造の維持管理技術を確立した。本研究の成果に対する学術的意義としては、先ず、高力ボルトおよび連結板ともに特徴的な腐食減肉形状を示すことから、その耐力評価は容易ではなく、鋼構造工学・維持管理工学の分野で研究途上であったが、本研究により、その腐食減肉形状に応じた残存軸力および継手耐力評価法の構築により、鋼構造物の腐食の弱点である高力ボルト継手構造の安全性評価法を提示したことは学術的価値が高い。