Analytical developments for a probabilistic seismic hazard analysis which allows a separate treatment of different sources of uncertainties

In this paper a specific Probabilistic Seismic Hazard Analysis is developed, which allows to obtain a relationship between given hazard levels and the statistical characteristics of the ensemble of the response spectral ordinates, as computed at multiple periods, of a group of earthquake inputs, herein referred to as “spectral cloud”. This statistical characterisation may be used for the identification of groups of design seismic records for Performance-Based Seismic Design applications. The here developed characterisation of the spectral cloud is rooted on the definition of the “epsilon” parameter which basically encompasses the uncertainties related to the error of the ground-motion prediction (attenuation) model.