端部混锚CFRP加固混凝土界面黏结性能模型

现阶段工程实际中CFRP加固钢筋混凝土构件采用的纯粘贴CFRP的方法，容易发生CFRP片材的早期剥离破坏，大大降低了加固效果，采用端部混锚技术可以有效改善该问题。为丰富端部混锚技术加固理论，研究端部混锚技术对CFRP加固混凝土界面黏结性能的影响，结合指数型双参数黏结-滑移本构模型，利用叠加法建立了端部混锚CFRP加固混凝土界面黏结行为理论模型，得到了界面荷载-滑移曲线、界面黏结剪切应力、CFRP正应力和应变分布表达式。并设计进行了端部锚固加固混凝土试件的单面剪切试验，将试验数据与理论公式进行了对比分析，验证了解析推导公式的正确性。此外，经参数分析可知，界面参数A对界面剥离荷载值和相对应滑移值的影响最大；当黏结长度小于有效黏结长度时，剥离荷载及对应的加载端滑移都会明显减小。

Bond performance model of concrete-to-CFRP interface with hybrid end anchorage

For the external bonded CFRP strengthening method in engineering practice, the premature peeling damage at the end of CFRP sheets is easy to occur, which may greatly reduce the strengthening effect. Through the experimental study, it is found that the hybrid end anchorage technology can effectively solve this problem. In order to enrich the theory of hybrid end anchorage technology and to study the influence of end anchorage technology on the bond performance of CFRP-to-concrete interface, combining the exponential two-parameter bond-slip constitutive model, the superposition method was used to establish the bond performance models of the CFRP-to-concrete interface with hybrid end anchorage. With this method, the analytical expressions of the interfacial load-slip relationship, the corresponding interfacial bond shear stress distribution, and the stress and strain distributions of CFRP were obtained. The proposed analytical expressions were verified by comparing the experimental data with the predictions of the theoretical formula for the designed single shear tests of CFRP-to-concrete interface. In addition, according to the parametric analysis, the interface parameter A has the greatest influence on the debonding load value and the corresponding slip value of the interface. When the bonding length is less than the effective bonding length, the debonding load and the corresponding load end slip are both significantly reduced.