大跨桥梁结构损伤预警的基本原理与方法

以润扬长江公路大桥为例,系统阐述了以小波包能量谱为基础的结构损伤预警方法的理论基础和本质特征。研究了以小波包分析为基础的结构动力系统的多尺度分解原理,推导了不同分析尺度上振动结构的状态方程和观测方程,并分析了结构系统矩阵和观测噪声的小波包分解特性,从理论上证明了基于小波包能量谱的结构损伤预警的敏感性和噪声鲁棒性。指出大跨桥梁结构损伤预警的有效性须考虑结构损伤和观测噪声的共同影响,并根据噪声能量的小波包分解特性提出了大跨桥梁结构损伤预警参数的计算方法。

The Basic Principle and Method of Structural Damage Alarming for Long-Span Bridges

A systematic discussion is made on the theoretical basis and innate characters of the structural damage alarming based on wavelet packet energy spectrum with the multiscale decomposition theory of the dynamic structure. The state equation and observation equation under various analysis scales are derived using wavelet packet analysis together with the wavelet packet decomposition of system matrix and observation noise, which reveal that structural damage alarming using wavelet packet energy will have preferable damage sensitivity and noise robusticity. The effectiveness of structural damage alarming for long-span bridges is subjected to structural damage and observation noise; structural damage alarming parameters are constructed according to the wavelet packet decomposition of noise energy.