基于宏应变监测的CFRP板桥梁加固预应力评估理论研究

Theoretical Study on Prestress Evaluation of CFRP Slab Bridge Reinforcement Based on Macro-Strain Monitoring

为实现对预应力CFRP板桥梁加固初期和后期预应力损失进行快速监测评估,采用新型分布式监测手段,推导了桥梁结构在端锚全粘贴预应力CFRP板加固后的梁底混凝土的长标距应变数值求解方法,并在此基础上提出了静、动态预应力CFRP板的预应力损失监测评估指标;然后通过数值算例,建立了精细化预应力CFRP板加固多片小箱梁的三维数值分析模型,研究不同车辆参数和不同预应力加固水平对上述静、动预应力损失评估方法精度的影响。研究结果表明:各预应力损失工况下静态预应力损失评估方法误差小于2.0%,动态预应力损失评估方法误差小于2.8%,证明所提方法的准确性和理论可行性,为相关试验研究奠定理论基础。

To quickly monitor and evaluate the prestress loss of Prestressed CFRP plate bridge in the early and late stage of reinforcement, a new distributed monitoring method is adopted to derive the long gauge strain numerical solution method of the concrete at the bottom of the beam after the end anchor is fully bonded with prestressed CFRP plate. On this basis, the prestress loss monitoring and evaluation indexes of static and dynamic prestressed CFRP plate are proposed;Then, through numerical examples, a three-dimensional numerical analysis model of multi piece small box girder strengthened with refined prestressed CFRP plate is established to study the influence of different vehicle parameters and different prestressed reinforcement levels on the accuracy of the static and dynamic prestress loss evaluation method. The results show that the error of static prestress loss evaluation method is less than 2.0%, and the error of dynamic prestress loss evaluation method is less than 2.8%,which proves the accuracy and theoretical feasibility of the proposed method.