预应力混凝土桥梁模态参数识别方法

目的为探讨基于环境激励下功率谱峰值法对于混凝土桥梁模态参数识别的可行性和方法的有效性．方法对某一预应力混凝土连续梁桥进行了数值仿真分析．借助通用有限元分析软件建立了桥梁的三维实体模型，对模型进行有限元模态分析和时程分析，并借助随机行车荷载模拟环境激励，利用加速度信号、考虑外界白噪声的影响，在仅有输出响应信号的情况下利用功率谱峰值法识别预应力混凝土桥梁的模态参数．结果通过数值仿真分析，得到了结构前六阶模态参数，与有限元模态分析得到的理论模态参数相比较，二者误差平均在5％以内，吻合较好．结论研究表明功率谱峰值法适合于环境激励下桥梁结构的监测、诊断，具有重要的实际工程应用价值．

Research on Modal Identification Method of Pre-Stressed Concrete Bridge

To study validity of power spectrum density peak method used to identify modal parameter of concrete bridge under ambient excitation,number simulation of one pre-stressed concrete bridge is carried out. 3D model of the bridge is established by FEM software, FEM analysis and time-history analysis of 3D model of PC continuous beam bridge are done. During the simulation, practical factors such as acceleration measuring and white noise are taken into account. In the only case of the output signal, modal parameter of bridge can be identified. Six-order modal parameters of the structure are identified by the number simulation whose average error is less than 5%. It is revealed that power spectrum density peak method is suitable for bridge＇ s monitoring and diagnosis and it is valuable in the application to practical engineering.