Estimation of residual seismic resistance of damaged steel member in buildings

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06635
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Building structures/Materials
• Research Institution: Yokohama National University
• Principal Investigator: Matsumoto Yuka 横浜国立大学, 大学院都市イノベーション研究院, 教授 (70313476)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 鋼構造 / 被災建築物 / 塑性変形 / 局部座屈 / 面外変形 / 残余耐震性能

Outline of Final Research Achievements

The aim of this study is to derive the estimation method of residual seismic resistance of steel members which have been plastically damaged by severe earthquake. A measuring method of section shape was proposed for on-site inspections in order to detect out-plain deformation due to slight local buckling.
The target is square-HSS members manufactured from BCR295, and I-shaped members manufactured from SN400B. A series of cyclic loading tests and finite element analysis was carried out and the out-plain deformation of the section’s flange,δo, and cumulative plastic deformation was investigated. The width-to-thickness ratio and axial force were taken as parameters. As the result, δo /B, the normalized δo by flange width was proportional to fourth power of the width-to-thickness ratio and square of the axial force ratio, and an equation　for square-HSS column was derived to approximate the relation between the δo /B and cumulative plastic deformation.

Free Research Field

鋼構造

Academic Significance and Societal Importance of the Research Achievements

近年、被災後の建築物の継続使用や迅速な復旧、交通などの都市機能の保全を求める機運が高まり、従前よりも巨大地震に対する構造骨組の損傷を低減させる設計が志向されるようになった。これらの良質な建築ストックを被災後も有効に活用するためには、構造骨組の損傷や残余耐震性能を判定する技術が必要となる。
一方、鋼構造建築物は損傷の度合いを段階的に推定することが困難であり、被災後の残余耐震性能を判定する技術は確立されていない。本研究は、鋼部材の局部座屈波形を計測する方法を提案し、塑性変形による損傷と局部座屈波形の関係を解明したものであり、残余耐震性能の判定方法を改善する上で有用な知見を与えている。