Location

Arlington, Virginia

Date

16 Aug 2008, 8:45am - 12:30pm

Abstract

This paper aims to determine the dependence of seismic response on the shape of the time-domain filter used in the stochastic method of ground motion prediction. Brune’s single-corner point source model was used in conjunction with the current attenuation relationships developed for hard rock sites in the Eastern North America (ENA) to obtain the target ground motion spectrum. A total of three hundred synthetic accelerograms were generated by filtering the Gaussian white noise with exponential, triangular and trapezoidal windows. For each accelerogram, displacement response of the Duffing’s oscillator was calculated, and its average amplitude spectrum was constructed in the joint time-frequency domain using Mexican hat wavelets. This procedure was repeated for three levels of nonlinearity. Among the three shapes examined, the trapezoidal window was associated with longer durations of sustained energy, thereby increasing the level of the expected damage. The dependence of the seismic response to the particular filter shape became more pronounced with increased levels of nonlinearity. This study concludes that ground motions with the same Fourier Amplitude Spectrum could cause substantially different levels of seismic damage on the same structure, depending on the time-frequency localization of the energy imparted to the structure.

Department(s)

Civil, Architectural and Environmental Engineering

Meeting Name

6th Conference of the International Conference on Case Histories in Geotechnical Engineering

Publisher

Missouri University of Science and Technology

Document Version

Final Version

Rights

© 2008 Missouri University of Science and Technology, All rights reserved.

Creative Commons Licensing

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Aug 11th, 12:00 AM Aug 16th, 12:00 AM

Generating Realistic Ground Motions for Nonlinear Seismic Hazard Analysis — An Application to Hard Rock Sites in Eastern North America

Arlington, Virginia

This paper aims to determine the dependence of seismic response on the shape of the time-domain filter used in the stochastic method of ground motion prediction. Brune’s single-corner point source model was used in conjunction with the current attenuation relationships developed for hard rock sites in the Eastern North America (ENA) to obtain the target ground motion spectrum. A total of three hundred synthetic accelerograms were generated by filtering the Gaussian white noise with exponential, triangular and trapezoidal windows. For each accelerogram, displacement response of the Duffing’s oscillator was calculated, and its average amplitude spectrum was constructed in the joint time-frequency domain using Mexican hat wavelets. This procedure was repeated for three levels of nonlinearity. Among the three shapes examined, the trapezoidal window was associated with longer durations of sustained energy, thereby increasing the level of the expected damage. The dependence of the seismic response to the particular filter shape became more pronounced with increased levels of nonlinearity. This study concludes that ground motions with the same Fourier Amplitude Spectrum could cause substantially different levels of seismic damage on the same structure, depending on the time-frequency localization of the energy imparted to the structure.