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

Abstract:

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.