2021 Fiscal Year Final Research Report

Proposal of seismic evaluation method for existing bridge footing considering the influence of piles and seismic retrofitting method corresponding to its fracture mode

Research Project

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Project/Area Number	20K14819
Research Category	Grant-in-Aid for Early-Career Scientists
Allocation Type	Multi-year Fund
Review Section	Basic Section 22020:Structure engineering and earthquake engineering-related
Research Institution	Public Works Research Institute
Principal Investigator	Yang Yong 国立研究開発法人土木研究所, 土木研究所(構造物メンテナンス研究センター), 専門研究員 (20867733)
Project Period (FY)	2020-04-01 – 2022-03-31
Keywords	フーチング / 杭列 / 破壊形態 / 破壊メカニズム / 耐震評価 / 耐震補強
Outline of Final Research Achievements	In this study, we proposed a seismic evaluation method for footing considering the influence of piles and a seismic retrofitting method corresponding to its fracture mode, by loading test and numerical analysis. In the proposed seismic evaluation method, the influence of the pile arrangement on the fracture mechanism of the footing was investigated. The effective width was set as the full width to accurately evaluate the bending strength of the inspection cross section of the footing. In addition, a correction coefficient has been newly introduced to consider the increase of bending strength of footing due to the influence of pile arrangement. In the seismic retrofitting method, a grid-like reinforcing material was adopted corresponding to the footing fracture mode, and the reinforcement details were designed for practical bridge structure. The reinforcement effect was confirmed from the viewpoint of crack restraint and integration of reinforcing material and footing.
Free Research Field	構造工学　耐震工学
Academic Significance and Societal Importance of the Research Achievements	本研究では、フーチングを単純な梁部材として耐震評価及び耐震補強を行う現状に対して、杭の影響を新しく考慮したフーチングの破壊メカニズムを解明した上で、高精度な耐震評価法を、また、施工性の高い、かつ有効的な耐震補強法を提案した。限られた財源を効率よく利用する観点からみると、高精度な耐震評価法により膨大な数の既設道路橋基礎の耐震補強優先順位を合理的に決めることが期待できる。また、耐震補強法を実橋に適用することにより、自然災害に負けない社会づくりに貢献することも期待できる。