Seismic Design of PC Beam with Opening

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04445
• 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: Shizuoka Institute of Science and Technology
• Principal Investigator: maruta makoto 静岡理工科大学, 理工学部, 教授 (30416763)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: プレストレストコンクリート / 有孔梁 / 耐震設計法 / 円形開口 / 補強方法

Outline of Final Research Achievements

A study on a shear design method for prestressed concrete (PC) beam with an opening was perforated. Even if the current an opening of PC beam is a circular, it is regarded as a rectangular opening indicated. On the other hand, for reinforced concrete (RC) beams, a reinforcement method using only diagonal reinforcement and near-hole reinforcement is shown. Even for PC beams with a circular opening, the shear design method under the allowable stress and under the ultimate shear strength with diagonal reinforcements and reinforcements near the hole. By organizing the past experimental results, experimenting with 4 PC beams, and analyzing non-linear finite elements, the shear crack strength and ultimate strength around the opening are determined, assuming that 10% of the axial force is effective for shear. The experimental results could be evaluated well by the added evaluation formula.

Free Research Field

工学(建築構造学）

Academic Significance and Societal Importance of the Research Achievements

プレストレスが作用することで，PC有孔梁のせん断強度はRC梁より，せん断ひび割れ強度，せん断終局強度とも大きくなった。これは実験からもまた，弾塑性FEM解析からも分かった。また，開孔が片側に偏った場合でも，せん断強度は変化しないことも解析から分かった。
PC有孔梁の円形開口の補強を，斜め筋と孔際補強筋で行い，そのせん断強度の評価の方法を示すことで新たな設計方法として世の中に提示できたことの意義は大きい。