Identification of Structural Stiffness Parameters via Wavelet Packet from Seismic Response

Vibration-based damage assessment approaches are conventionally and widely adopted to monitor the structural health of a building during the bases excitation process. This study explores the possibility of using structural stiffness parameters to locate the storeys of building that are damaged in an earthquake event. A damaged storeys usually exhibits stiffness parameters variations during a strong enough earthquake, and the corresponding stiffness of storey often change in the earthquake. The wavelet packet transform is applied to the measured acceleration responses of a structure to reconstruct the autoregressive with exogenous input (ARX) model in wavelet packet domain. The modal parameters of the structure are estimated directly through the identified coefficient matrixes of the ARX model. Next, the stiffness parameters of the structure that could be reconstructed form the identified natural frequencies and mode shapes would be used to detect the damage locating of a building. The accuracy of this procedure is numerically confirmed, the effects of the wavelet parameters and noise on the ability to accurately estimate the dynamic properties are also investigated.