FRP补强加固RC梁粘结破坏机理研究

根据FRP(Fiberreinforcedplastic)补强加固RC梁的试验结果,总结了FRP补强加固钢筋混凝土受弯构件早期破坏形态的过程和特点。FRP加固钢筋混凝土抗弯构件粘结界面的剪应力的分布在纤维截断点处存在较高的应力集中,随着离截断点距离的增大剪应力分布逐渐趋于均匀,粘结锚固长度不足和过高的应力集中是造成FRP加固钢筋混凝土构件早期破坏的主要原因。采用“齿”状块体力学计算模型和混凝土裂缝理论分析了FRP加固钢筋混凝土受弯构件时需要的有效锚固长度,并通过简化修正得出了FRP加固钢筋混凝土受弯构件最小锚固长度的计算公式,提出了FRP的容许应变值和避免FRP早期破坏应采取的措施,可供FRP加固工程设计和施工参考。

Mechanism research of debonding failure of strengthening RC beam with externally-bonded FRP

Based on the test results of RC beam strengthened with externally bonded FRP(fiber reinforced plastic), this paper summarized the premature failure form characteristic and process of reinforced concrete members strengthened with externally bonded FRP, the interfacial shear stress is maximum at the FRP cut off point and starts to decay as the distance from the cut off point x is increased, and the insufficiency and the high interfacial shear stress concentration in the plate containment region are the main causes leading to the failure of reinforced concrete members strengthened with externally bonded FRP. According to the distribution of interfacial shear stress, this paper also analyzes the effective anchorage length of FRP with the mechanical model of tooth block and crack theory of concrete, works out the calculating formula of least anchorage length of FRP for strengthening reinforced concrete beam with further simplified correction, and finally puts forward the tolerance strain value of FRP and the measures taken to avoid the premature failure of FRP, which provide theory basis for design and construction of strengthening with externally bonded FRP.