Abstract

External bonding of fibre-reinforced polymer (FRP) plates has emerged as a method for strengthening reinforced concrete structures. The creep of the concrete, adhesive and FRP can accelerate debonding along with the interface. In this paper, an original creep model is developed to study the long-term behaviour of combined cohesive-bridging model of an FRP–concrete interface, debonding under axial loading. A combined cohesive-bridging zone model is presented to simulate long-term debonding between the FRP plate and concrete beam interface. Four zones are distinguished and thoroughly analysed: elastic, softening, bridging and debonding. An original behaviour law is proposed, combining the creep modelling of the various materials. A new analytical model of the long-term shear stress distribution along the interface is developed. For application data, the bond-slip parameters for a real-time combined cohesive-bridging model along the FRP–concrete interface are determined by calibration based on the experimental and analytical data in the pre-existing literature. The simulation of the long-term bond-slip law of the FRP–concrete interface is based on the constant fracture energy G_f and shearing rigidity of the interface. The parametric study suggests that to extend the durability of an FRP–concrete interface, loads should be in the elastic stage, and thick, highly rigid FRP plates should be used.

摘要

纤维增强聚合物 (FRP) 板的外部粘合已成为加强钢筋混凝土结构的一种方法。混凝土、胶粘剂和 FRP 的蠕变会随着界面一起加速脱粘。在本文中，开发了一个原始蠕变模型来研究 FRP-混凝土界面的组合黏聚桥接模型在轴向载荷下脱粘的长期行为。提出了一种组合的内聚桥接区模型来模拟 FRP 板和混凝土梁界面之间的长期脱粘。四个区域被区分和彻底分析：弹性、软化、桥接和脱粘。结合各种材料的蠕变建模，提出了一个独创的行为定律。建立了沿界面的长期剪应力分布的新分析模型。对于应用程序数据，沿 FRP-混凝土界面的实时组合黏性桥接模型的粘结滑移参数是根据现有文献中的实验和分析数据通过校准确定的。FRP-混凝土界面长期粘结滑移规律的模拟基于恒定断裂能G _f和界面的剪切刚度。参数研究表明，为了延长 FRP-混凝土界面的耐久性，载荷应处于弹性阶段，并且应使用厚的、高刚性的 FRP 板。