大跨度斜拉桥模态参数识别时频方法对比研究

利用苏通大桥结构健康监测系统(SHMS)记录的台风期间大桥加速度响应,分别基于希尔伯特-黄变换(HHT)和小波变换(WT)方法对该桥进行了模态参数识别,并将2种识别结果进行对比.在此基础上,进一步研究了模态阻尼比与桥址区实测平均风速的关系.结果表明:基于HHT和WT方法识别出的模态频率值基本一致;模态阻尼比差距较大,基于HHT方法识别的阻尼比均值略大于基于WT方法的识别结果;基于HHT和WT方法识别的模态阻尼比随风速的变化趋势类似.

Comparison Study on Modal Parameter Identification of Large Span Cable Stayed Bridge With Time frequency Method

Acceleration responses of Sutong Bridge during typhoon Haikui were recorded by structural health monitoring system (SHMS). On the basis of recorded data, the modal parameter identification of the bridge was conducted with Hilbert Huang transform (HHT) and wavelet transform (WT) methods, and the identified results were compared with each other. Then, the relationship between modal damping ratios and measured mean wind speed at the bridge site was studied. Results show that the identified modal frequencies based on the HHT method are almost the same with the WT based modal frequencies. However, the difference between modal damping ratios is larger, which exhibits that the mean values of HHT based damping ratios are larger than those WT based results. Besides, the wind speed related varying trends of modal ratios identified by the HHT method are identical with those by the WT method.