Structural dynamic and aerodynamic parameters identification for a tall building with full-scale measurements

Based on the two sets of acceleration response data, full-scale measured on a 270 m tall building in Hong Kong during Typhone Kammuri and 512 Wenchuan earthquake in 2008, the dynamic modal properties of the tall building were identified by two methods. One is the traditional method of empirical mode decomposition (EMD) combined with the random decrement technique (RDT), the other is the recently proposed fast Bayesian method using the fast Fourier transform (FFT). The natural frequency of each mode identified by these two different methods is very close to each other, while noticeable difference is observed between the damping ratio results corresponding to each mode. The identified results under the two excitation events were also compared. As expected, the wind-induced acceleration data suggest almost the same natural frequency values as those identified from the acceleration data under the long-distance earthquake. However, the damping ratios of the tall building corresponding to Wenchuan earthquake are found to be larger than those under typhoon excitation. The subtraction results between these two sets of damping ratios might be considered as the estimation values of aerodynamic damping ratios.