The Earthquake Engineering Online Archive

Influence of the earthquake ground motion process and structural properties on response characteristics of simple structures

Conte, Joel P.; Pister, Karl S.; Mahin, Stephen A.

UCB/EERC-90/09, Earthquake Engineering Research Center, University of California, Berkeley, 1990-07, 341 pages (526/C66/1990)

A quantitative description of the uncertainty or inherent variability of earthquake ground motion input into structures is proposed. It utilizes a time-varying discrete autoregressive moving-average (ARMA) stochastic process able to reliably capture the amplitude and frequency nonstationarities typical of real earthquake records. Two earthquake records are analyzed and simulated using the proposed ARMA modeling procedure. The fitted earthquake models are used as seismic input into simple elastic and inelastic structural models. The resulting stochastic response processes are characterized using various elastic and inelastic response parameters. The models are checked thoroughly for: (1) "whiteness" and normality of residuals, (2) simulation of stochastic elastic response, and (3) simulation of stochastic inelastic response. A comprehensive parametric study using ARMA Monte Carlo simulation is used to assess the stochastic nature of the seismic response of structures. The sensitivities of the probability distributions of the various response parameters with respect to the earthquake process, the type of structural behavior, and the structural properties are obtained. The absolute and relative levels of variability of the traditional ground motion parameters, the elastic response parameters, and the inelastic response parameters are also investigated. The results of this study can be directly used for seismic reliability assessment of simple structures using formal reliability theory. The ARMA Monte Carlo simulation methodology can be integrated into the formulation of reliability-based seismic design procedures that can admit some tolerable degree of damage while minimizing the risk of collapse.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-90-09.pdf (21 MB)