Proposal of Emergency Retrofitting Method by Jacketing of PVA-FRM Spraying to Restore RC Columns

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04664
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22020:Structure engineering and earthquake engineering-related
• Research Institution: University of Fukui
• Principal Investigator: ISO Masato 福井大学, 学術研究院工学系部門, 教授 (60377471)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 耐震補強工法 / 応急復旧補強工法 / 既存鉄筋コンクリート柱 / ポリビニルアルコール繊維補強モルタル吹付け / スポット溶接 / 溶接組立鉄筋 / RC巻き立て補強工法 / せん断補強効果

Outline of Final Research Achievements

In this study, we developed an emergency recovery reinforcement method in which existing reinforced concrete columns damaged by earthquakes and other disasters are retrofitted into steel bar units by spot welding under highly quality control, and then polyvinyl alcohol fiber reinforcement mortar (PVA-FRM) is sprayed to improve structural performance.
It was clarified that this retrofit method is effective for shear reinforcement and can improve shear strength and toughness performance as the amount of shear reinforcement increases. In addition, the test specimen fractured by shear fracture to a degree of damage IV is repaired with epoxy resin injection and polymer cement mortar, and then the test specimen reinforced by this retrofit method can also improve the shear strength and toughness performance. And they can be sufficiently applied as an emergency recovery method.

Free Research Field

鉄筋コンクリート構造

Academic Significance and Societal Importance of the Research Achievements

本研究では，地震後に被災した既存不適格建物の鉄筋コンクリート柱を対象に，構造性能を簡易かつ迅速に回復できる応急復旧工法（スポット溶接によりユニット化した組立鉄筋を閉鎖型に組立て補強し，PVA-FRMを吹き付けてせん断補強する工法）を開発し，その設計に必要な構造性能を示すと同時に，その設計手法を提案した。
本研究及びその成果の学術的意義であるが，ユニット化した鉄筋およびPVA-FRMを用いた応急復旧工法の提案は，世の中で初めてであり，その学術的意義は大きい。また，現在は地震の活動期にあり，地震被災後には迅速な復旧が求められる。本応急復旧工法は，その一助となるものである。