基于大应变FRP加固的RC桥墩抗冲击性能研究

本项目采用一种新型的大应变FRP材料（Large-rupture-strain FRP, 简称LRS FRP, 断裂应变大于5%）来实现RC桥墩抗冲击性能提升。大应变FRP材料断裂应变大的特点可以增加RC桥墩的延性，防止桥墩垮塌；而其低弹性模量的特点使外包FRP在侧向荷载作用的初始阶段可能随RC桥墩共同变形，在一定程度上实现“柔性”加固。以大应变FRP加固RC桥墩为研究对象，逐步开展大应变FRP约束混凝土动态压缩性能、大应变FRP-混凝土界面动态粘结关系和大应变FRP加固RC桥墩侧向抗冲击性能研究。探索应变率对大应变FRP约束混凝土抗压性能、FRP与混凝土界面粘结性能及FRP加固桥墩抗冲击性能的影响，揭示冲击荷载作用下大应变FRP约束RC柱中FRP与内部钢筋的相互作用机理，发展大应变FRP加固RC桥墩抗冲击性能评估方法，建立大应变FRP加固RC桥墩的在冲击荷载作用下的承载力经验公式。

This project innovatively adopts a new kind of FRP named large-rupture-strain FRP (LRS FRP, with rupture strain >5%) to enhance the anti-impact capacity of bridge piers. The large rupture strain characteristic of LRS FRP may lead to a favorable deformability and the low elastic modulus will induce synchronous deformation of the FRP wrapping with the RC column at the initial stage of impact loading, thus to some extent , resulting a flexible anti-collision pier structure. This project will start with the dynamic compressive behavior of LRS FRP-confined concrete, followed by the dynamic bond behavior of LRS FRP-concrete interface, and the impact behavior of LRS FRP strengthened RC piers. The strain rate effects on the compressive behavior of LRS FRP-confined concrete and bond behavior of LRS FRP-concrete interface will be explored. The interaction mechanism between FRP and internal steel reinforcement in LRS FRP-strengthened RC piers will also be investigated. The implementation of this project will provide a better understanding of the impact behavior of LRS FRP-strengthened RC piers and finally lead to the further establishment of the design equations for loading capacity of and the evaluation method for the anti-impact capacity of LRS FRP- strengthened RC piers.