Non-Destructive Detection Method for Internal Damage and Degradation in Seismic Isolation Rubber Bearings

2024 Fiscal Year Final Research Report

• Project/Area Number: 23K19148
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
• Research Institution: Kumamoto University
• Principal Investigator: Watanabe Shinya 熊本大学, くまもと水循環・減災研究教育センター, 助教 (60980472)
• Project Period (FY): 2023-08-31 – 2025-03-31
• Keywords: 構造力学 / 非破壊検査 / 維持管理 / 免震ゴム支承 / デジタル画像相関法 / 鋼構造

Outline of Final Research Achievements

In this study, the deformation performance of seismic isolation rubber bearings with internal damage was evaluated through numerical analysis. In addition, the feasibility of detecting internal damage from the surface of the rubber cover was investigated by measuring the surface strain distribution.
Specifically, a numerical model was developed to represent seismic isolation rubber bearings used in actual bridges. Interfacial debonding between the steel plates and rubber layers was introduced into the model as a damage parameter, and a series of case studies were conducted.
The results demonstrated that, regardless of the location where the interfacial debonding occurred, it is possible to detect such internal damage by measuring the average strain distribution on the surface of the rubber cover of the seismic isolation bearing.

Free Research Field

維持管理

Academic Significance and Societal Importance of the Research Achievements

本研究では，橋梁に広く用いられている免震ゴム支承に着目し，その健全性評価手法の確立を目的とした．免震ゴム支承は，橋梁において極めて重要な免震機構であるが，現在の維持管理においては，内部の劣化や損傷を把握するための実効的な手法は確立されていない．
本研究で提案する手法は，免震支承の内部状態を可視化・定量化するものであり，これまで困難とされてきた供用下での支承内部の劣化検出を可能とする点で，新規性と独自性を有し，健全性評価の高度化を期待しうるものである．また，社会基盤施設の予防保全型維持管理を実現し，インフラの長寿命化や災害に強い社会の構築に直結するものであり，社会的意義も極めて大きいといえる．