Development of Mobile Technique for Emergency Retrofit of Shear-damaged RC Columns Using Fiber-belt Prestressing

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K04794
• 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: University of the Ryukyus
• Principal Investigator: NAKADA Kozo 琉球大学, 工学部, 教授 (80347129)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: プレストレス / 横拘束 / 拘束コンクリート / 応急補強 / 軸耐力 / せん断破壊 / リハビリテーション

Outline of Final Research Achievements

The ultimate purpose of this research is development of a simple, quick, and inexpensive mobile-emergency retrofitting technique to close the cracks of shear-damaged reinforced concrete (RC) columns via applying active lateral confinement pressure using fiber belts. In this study, the shear transition mechanism, and the recovery of seismic performance of shear-damaged RC columns retrofitted using mobile emergency technique were examined under the axial compressive and lateral loading tests. The results showed that: 1) applying active lateral confinement pressure on the shear-damaged RC columns largely restored their flexural strength, but smaller stiffness recovery was observed; 2) Applying active lateral confinement pressure led to a more efficient shear reinforcement; 3) Use of epoxy resin in conjunction with applying active lateral confinement pressure resulted in a significant recovery of both lateral strength and stiffness of shear-damaged RC columns.

Free Research Field

建築構造学

Academic Significance and Societal Importance of the Research Achievements

本研究の重要なキーワードは，コンクリートをあらかじめ締付ける「能動横拘束」である。能動横拘束効果によって，コンクリートの圧縮強度は増大する。本研究では，この能動横拘束を地震によってひび割れが生じた損傷RC柱の「ひび割れ閉合」に応用する点に学術的意義がある。また，本研究の成果は，（1）連続発生する大地震や余震における震災建築物の損傷進行を阻止し得る，（2）震災建築物付近の安全確保や不動財産の保全に繋がる，（3）応急仮設住宅等の需要や災害廃棄物発生量を抑制することにも繋がる，などの点から社会的意義があると考えられる。