Fan, Zenglei

Cross Evolutionary Power Spectra Estimation of Spatial Variable Seismic Ground Motions Using Generalized Harmonic Wavelets

Abstract eng:
Nonstationary characteristics of spatially variable seismic ground motions, which are mathematically described by cross evolutionary power spectra or evolutionary coherency, have significant effect on earthquake responses of nonlinear extended structures. Estimation and modeling of cross evolutionary power spectral density (EPSD) of spatially variable seismic ground motions are of interest in recent years for engineering purposes. This article presents an approach for estimating the cross EPSD of the spatially variable seismic ground motions by using the generalized harmonic wavelets (GHW). The cross EPSD and the evolutionary lagged coherency of the realistic spatially variable seismic ground motions are estimated by this approach. The time-varying nonstationary characteristics of these ground motions are also analyzed. First, after a brief review of the former studies in wavelets-based evolutionary spectra estimation, a cross EPSD estimation formula is derived using the GHW within the framework of evolutionary spectra estimation given by Spanos & Failla. Then, the proposed estimation formula is used to estimate the cross EPSDs of the seismic ground motions recorded at the SMART-1 array during Event 45. The cross EPSDs and the evolutionary lagged coherency between the center station and the outer ring stations, at separation distances of 2000m, are obtained. The comparisons of the estimated lagged coherency at different times indicate that the correlation of the spatially variable seismic ground motions is time-dependent. During the stable stage of the ground-motion intensity, the lagged coherency is close to 0.8 in the low frequency range and decays as frequency increasing. During the rising and decaying stages of the ground-motion intensity, the lagged coherency is fluctuant with a mean value of about 0.4.

Contributors:

Wang, Ding

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

Text je chráněný podle autorského zákona č. 121/2000 Sb.