一种基于冲击响应的装配式板梁桥铰接缝病害动力评估方法

摘要

提出一种基于冲击响应频响函数和模型修正理论的装配式板梁桥铰接缝病害动力评估方法.将铰接缝整体平均刚度作为待识别变量,以特定频率段内的频响函数相关性指数构造目标函数,改进既有的有限元模型修正技术,从而实现对病害铰接缝的定位以及损伤程度的定量识别.数值分析结果表明:利用文中所提方法可实现对全桥多个铰接缝不同程度病害的同步识别,且计算效率高;所提方法抗噪能力较强,可保证收敛到全局最优解;冲击荷载施加位置和测点布置位置对病害识别结果影响较小.对某装配式板梁桥进行现场动力试验,更新改造前后评估结果与桥梁实际状态相符,从而从实际应用角度证明所提方法的可靠性和实用性.%A dynamic evaluation method for damage evaluation of hinged joints in fabricated slab-girder bridge using frequency response function (FRF) and model updating theory is proposed. The integral average stiffness of hinged joints is taken as the identification variable, the correlation indexes of FRFs (COFRF) between adjacent girders is used to construct the objective function, based on which the model updating method is improved and optimized for localization and quantitative identification of hinged-joint damage at different locations. A numerical simulation example is given, in which the influence of some factors, including the damage degree, number and locations of damaged joints, locations of impact load, locations of measurement points and the noise on the damage identification results, is analyzed. The analysis results show that multiple hinged-joint damage with different degrees can be identified simultaneously by the proposed method with good anti-noise ability and good calculation efficiency. Locations of impact load and measurement points have little influence on the identification results. A fabricated slab-girder bridge was tested before and after renovation. The evaluation results agree well with the actual damage, which proves the reliability and effectiveness of the proposed method from the view of practical application.