基于地震激励的混凝土桥梁模态参数识别

为探讨基于地震激励下自然激励技术(NExT)结合特征系统实现算法(ERA)对于混凝土桥梁模态参数识别的可行性,对某一预应力混凝土连续梁桥进行了数值仿真分析。通过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,并利用强震记录实现地震激励,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采用NExT/ERA方法识别预应力混凝土桥梁的模态参数。通过数值仿真分析,识别出结构前4阶模态参数,与有限元模态分析得到的模态参数相比较,二者误差较小,吻合较好。

Concrete bridge modal parameter identification under seismic excitations

To study validity of NExT/ERA method which be used to identify modal parameter of concrete bridge under seismic excitations,the number simulation of one pre-stressed concrete bridge was carried out.3D model of the bridge was established by FEM software.FEM analysis and time-history analysis of 3D model of PC continuous beam bridge were carried out.Seismic excitations was generated by strong earthquake records.During the simulation,practical factors such as acceleration measuring and white noise were taken into account.In the only case of the output signal modal parameter of bridge can be identified.Four-order modal parameters of the structure were identified by the number simulation.The error of the modal parameters between number simulation and FEM analysis is small.