基于纤维增强复合材料(FRP)与混凝土之间界面的粘结一滑移双线性模型,推导了预应力FRP片材加固受弯钢筋混凝土(RC)梁弯曲裂缝间界面的粘结剪应力,考虑了FRP预应力水平和裂缝间距对构件承载力的影响;以界面断裂能所对应的临界滑移量作为剥离判据,建立了界面起始剥离和剥离破坏的预测模型,并进行了实验验证.研究结果表明:利用该模型可以有效地预测受弯FRP片材加固RC梁的剥离状况及剥离破坏时的承载力;FRP的预应力水平越高或裂缝间距越小,加固梁的抗剥离承载力越大.
Based on the bilinear bond-slip model of the interface between fiber-reinforced polymer (FRP) and concrete, the interfacial bonding shear stress in the intermediate cracking zone of the reinforced concrete (RC) beam strengthened with prestressed FRP laminates under bending load was analyzed, and the effects of the prestress level and the crack spacing on the debonding load-carrying capacity were discussed. Moreover, some theoretical models to predict the initial debonding and the debonding failure were established, with the critical slip corresponding to the interfacial fracture energy as the debonding criterion. Some experiments were finally performed to verify the models. It is indicated that the proposed models effectively predict the debonding and the corresponding load-carrying capacity of RC beams strengthened with prestressed FRP laminates under bending load, and that the debonding load-carrying capacity improves with the increase of the prestress level of FRP and with the decrease of the crack spacing.