On the schematization of design response spectra as a stochastic model

This paper focuses on the identification of the characteristics that a group of earthquake inputs must possess in order to be associated to a given exceedance probability, for seismic design applications. The identification of the characteristics of the “group of uniform hazard time-histories” is deeply rooted upon their probabilistic identification and is here made with reference to the elastic response spectral ordinates, takes advantage of the information carried by the “epsilon” parameter, and is rooted on a separate treatment of the aleatory (intrinsic) variability and the epistemic uncertainty considered in the hazard analysis. The response spectra of the time-histories are described as a stochastic model: both (1) the probabilistic distribution functions of the spectral ordinates of given hazard (which depend on the period) and (2) the autocorrelation function of the spectral or-dinates are obtained.