2019 Fiscal Year Final Research Report

Characteristics and control of progressive collapse behavior of bridges under unexpectedly large earthquakes

Research Project

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Project/Area Number	16H02359
Research Category	Grant-in-Aid for Scientific Research (A)
Allocation Type	Single-year Grants
Section	一般
Research Field	Structural engineering/Earthquake engineering/Maintenance management engineering
Research Institution	Nagoya Institute of Technology
Principal Investigator	Yoshiaki Goto 名古屋工業大学, 工学(系)研究科(研究院), 教授 (90144188)
Co-Investigator(Kenkyū-buntansha)	野中哲也名古屋工業大学, 工学(系)研究科(研究院), 教授 (20772122) 小畑誠名古屋工業大学, 工学(系)研究科(研究院), 教授 (30194624) 海老澤健正名古屋工業大学, 工学(系)研究科(研究院), 助教 (90332709) 吉田純司山梨大学, 大学院総合研究部, 准教授 (90345695)
Project Period (FY)	2016-04-01 – 2020-03-31
Keywords	進行性破壊 / 耐震設計 / 崩壊制御 / 連続高架橋 / CFT橋脚 / 上路式トラス橋 / 振動台実験 / ロバスト性
Outline of Final Research Achievements	Collapse-control design is proposed to reduce the fatal damages of bridges caused by the progressive failure that may occur in case when structural responses exceed the safety limit states under unexpectedly large earthquakes. First, collapse tests were conducted on three 1/7 scale models of continuous elevated-girder bride specimens and two 1/5 scale models of upper-deck type truss bridges to assess their progressive failure behaviors precisely. Then, numerical models were presented such that the dynamic collapse behavior of the bridge models observed in the tests can be simulated accurately. Collapse criterions were also proposed to predict the failure of the bridges by the numerical models. Finally, the validity of the two methods to improve the resistance to the progressive failure was investigated. One is to increase the energy dissipation capacity of structural members in the post-peak range. The other is to install collapse prevention devices.
Free Research Field	耐震工学，構造工学，計算力学
Academic Significance and Societal Importance of the Research Achievements	橋の耐震設計では，通常，想定した地震動に対して，橋の応答が終局限界を超えないことの照査のみがなされる．このため，想定外の地震動で応答が終局限界を超えた場合には，崩壊などの深刻な被害が発生する恐れもある．しかし，橋の崩壊挙動の実態はほとんど未知であるので，問題を解決する有効な方策は提示されていない．したがって，本研究で，橋の崩壊挙動特性を実験で解明し，崩壊挙動を予測する精緻な解析モデルや崩壊判定法を構築したこと，さらに，崩壊制御設計の新しい枠組を提示したことには学術的意義がある．また，想定外の地震に対する橋の致命的崩壊を減災の観点から回避する具体的方策を提示したことには社会的意義があると考える．