PSHA-Based Design Spectrum: An Application of the Design Spectrum Predictive Model for Seismic Regulation Purposes

This paper represents the continuation of previous research works, in which a predictive model for spectral ordinates instrumental for design was developed. In particular, the objective of the present study is to show how to apply the model within a probabilistic seismic hazard analysis (PSHA). The model, which takes into account soil nonlinearity, is based on five parameters (i.e. peak spectral acceleration and displacement, their structural periods of occurrence and a parameter that controls the spectral ordinates at the intermediate period range), which are defined as a function of three different soil classes (i.e. rock, stiff soil, and soft soil). The outcome is a PSHA-based design spectrum (PBDS), which represents a direct tool for seismic design obtained from a PSHA. Examples of PBDS for Italy are also discussed and compared with the design spectra defined by the current Italian seismic code.