Improvement of ductility of rectangular cross-section steel members by using high performance steel.

Research Project

Project/Area Number	18K04331
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 22020:Structure engineering and earthquake engineering-related
Research Institution	Waseda University
Principal Investigator	ONO Kiyoshi 早稲田大学, 理工学術院, 教授 (60324802)
Co-Investigator(Kenkyū-buntansha)	穴見健吾芝浦工業大学, 工学部, 教授 (30272678) 宮下剛長岡技術科学大学, 工学研究科, 准教授 (20432099)
Project Period (FY)	2018-04-01 – 2021-03-31
Project Status	Completed (Fiscal Year 2020)
Budget Amount *help	¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000) Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000) Fiscal Year 2019: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000) Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Keywords	高性能鋼 / シャルピー吸収エネルギー / 高じん性 / 耐荷力 / 曲げ加工 / ひずみ時効 / SBHS / 橋梁用高性能鋼 / 残留応力 / ＳＢＨＳ / 機械的性質
Outline of Final Research Achievements	It is thought that rectangular cross-section steel members with cold-formed corner parts are effective for preventing the fracture of welding at corner parts in the huge earthquakes. In order to propose this type of structures by using high performance steel ‘SBHS’, the Charpy absorbed energy of cold-formed corner parts and the load-carrying capacity of the targeted structures were investigated. The results of Charpy impact tests indicated that Charpy absorbed energy at cold-formed corner parts is sufficiently high judging from the values specified in the design specifications for high bridges. The information on the load-carrying capacity was obtained by the experimental and numerical results and the evaluation method was proposed. Consequently, results obtained in this study indicate the feasibility of the targeted structures.
Academic Significance and Societal Importance of the Research Achievements	本研究で提案した，高性能鋼の特性を活用して角部から溶接部を無くして曲げ加工鋼板とした構造ディテールは，今後発生することが指摘されている東南海地震等の巨大地震に対しても，角部の溶接部が破壊することによって発生する鋼部材の倒壊を防止できる構造であるため，国土強靱化に資するものである．よって，本研究は高性能鋼の特性を活用した新たな構造の実現可能性を示すとともに，橋梁の地震に対する安全性を高める上で有用な情報を与えているため，学術的意義や社会的意義の高い研究であると言える．