Estimation of residual axial load Capacity of Pile Foundations considering ground resistance after severe earthquakes

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04698
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 23010:Building structures and materials-related
• Research Institution: Hiroshima Institute of Technology
• Principal Investigator: Kaneko Osamu 広島工業大学, 工学部, 教授 (80824135)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 建築構造 / 建築基礎構造 / 地盤工学 / 杭基礎 / 支持力 / 残存軸耐力 / 載荷試験 / 有限要素法

Outline of Final Research Achievements

Loading tests and analyses by Finite Element Method were conducted with the aim of using the bearing capacity of the building foundations considering the effect on the superstructure as index in seismic design against severe earthquakes or seismic evaluations.
According to the results of loading tests, it was confirmed that even if half of the piles were damaged settlement and inclination leading to fall or collapse of the superstructure would not be large unless the load was transferred to the ground and the bearing capacity of the entire foundation structure was finally lost. Parameter analysis was carried for the process of load transfer when the shape and pile arrangement were different, data on subsidence, inclination and the load sharing ratio of the ground and foundation slabs were obtained.
These results will lead to the establishment of a method for quantitatively evaluating the residual axial load capacity of pile foundations.

Free Research Field

工学

Academic Significance and Societal Importance of the Research Achievements

重要度が高い建物や地震後も機能維持が要求される建築物などでは，現行技術基準では義務付けられていないとしても大地震時の基礎構造の耐震性について検討が必要である．杭基礎建築物では杭体の損傷後に周囲の地盤に荷重負担が移行している状態を終局状態と考えることもできるが，杭体単体の耐震性能に関する研究は進められているものの，地盤を含む支持メカニズムの評価には至っていない．本研究により杭の損傷後の地盤も含む支持性能である残存軸耐力についてのデータを取得し，大地震に対する設計や耐震診断のための基礎構造の耐震指標としての確立につなげられれば，より合理的に建物全体としての安全性確保や機能維持が可能になる．