Synthetic Pulse Model for Near-Fault Effects on Structures

Abstract

The inclusion of near-fault effects is now required for building structures designed in accordance with ASCE 7-16 using nonlinear time history analysis. It is also a recognized problem for bridge structures, particularly those with long natural periods. Although existing ground motion databases contain thousands of records, this article shows that just a small percentage contain near-fault pulse-like ground motions. Hence a model for generating synthetic pulses to supplement the available near-fault ground motion data set is necessary and examined in this article. A family of analytic wavelets, known as generalized Morse wavelets, is considered for this purpose. This wavelet family is capable of modeling pulse-like ground motions, using the continuous wavelet transform, by varying two parameters that control wavelet shape and number of oscillations. Using a suite of ground motions that satisfy ASCE 7-16’s near-fault criteria, a model for generating synthetic pulses is created. A series of regression equations for the synthetic pulse model are presented to show the relationship between pulse parameters, peak ground acceleration, and moment magnitude.