2018 Fiscal Year Final Research Report

Cumulative Damage Estimation of Steel Piles under High-rige Buildings due to Dynamic Buckling Subjected to Long Period Earthquake

Research Project

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Project/Area Number	16H04445
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	Building structures/Materials
Research Institution	Tohoku University
Principal Investigator	Kimura Yoshihiro 東北大学, 未来科学技術共同研究センター, 教授 (60280997)
Co-Investigator(Kenkyū-buntansha)	古川幸東北大学, 工学研究科, 助教 (30636428) 田村修次東京工業大学, 環境・社会理工学院, 准教授 (40313837)
Project Period (FY)	2016-04-01 – 2019-03-31
Keywords	鋼管杭 / 動座屈 / 累積損傷評価 / 液状化 / 高層建築物 / 遠心載荷実験
Outline of Final Research Achievements	The estimation method of the steel pile’s ultimate strength in the liquefied soil collapsing due to the significant earthquake is suggested. However, there are some cases, in which the steel piles do not fail and can carry the dead load of the building due to the seismic motion. On the other hand, the steel pile, which has accumulated the damage due to long period earthquakes, might collapse when it experiences the subsequent massive earthquake. In this research, the centrifugal tests are conducted to clarify the steel piles' collapse behavior in the liquefied soil subjected to the multiple earthquakes. Moreover, the steel pile’s ultimate strength and cumulative damage estimation are estimated by numerical analyses.
Free Research Field	耐震構造
Academic Significance and Societal Importance of the Research Achievements	杭基礎の損傷の再現及び杭基礎の損傷度を予測するために，様々なパラメータに対して地盤・杭基礎－建物系の縮小模型実験を行うとともに，これまでの研究成果研究業績の知見を踏まえ，地震動特性や地盤特性と杭の損傷度との関係を明らかにし，高層建築物下における鋼管杭の累積損傷度評価法を提案できた。この評価法を元に，将来の予測地震動に対する杭の残存保有性能評価法を確立することで，大地震後に新たに生じる予測地震動に対する杭の保有性能と要求性能の関係性を把握し，杭の補強や取り替えの有無を提示することができた。以上より，大地震に対して安心・安全な社会を構築するための新たな設計法の確立に寄与することができた。