Stress transfer mechanism of RC beams with large web-opening, and proposal of shear capacity evaluation and reinforcing arrangement design method around web-opening

Research Project

Project/Area Number	25420574
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Building structures/Materials
Research Institution	University of Fukui
Principal Investigator	Kobayashi Katsumi 福井大学, 学術研究院工学系部門, 教授 (40150297)
Project Period (FY)	2013-04-01 – 2017-03-31
Project Status	Completed (Fiscal Year 2016)
Budget Amount *help	¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000) Fiscal Year 2015: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000) Fiscal Year 2014: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000) Fiscal Year 2013: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords	鉄筋コンクリート構造 / 開孔梁 / 人通孔 / 開孔周囲補強筋 / 終局せん断耐力 / 応力伝達メカニズム / せん断終局耐力 / 建築構造・材料 / 鉄筋コンクリート
Outline of Final Research Achievements	The shear force transfer mechanism around the web-opening was experimentally discussed, and the shear force transfer model was proposed. The diagonal bars form a truss structure and carry a part of shear force independently. The truss and arch mechanism of two stage beams upper and lower side of the web-opening carry the other part of shear force. The stirrups on the side of the opening balance with the strut of the arch mechanism. According to the shear capacity formula based on the proposed shear force transfer model, the calculated shear capacity corresponds to the experimental results with almost constant safety margin. The postulated formula in this study is found to be able to evaluate the shear capacity of RC beams with large web-opening accurately.