Seismic actions according to the recent Italian and European codes

This paper compares the elastic response spectra, prescribed by EC8 (2003) part 1, to those inferred by means of 1D equivalent - linear analyses in a number of well characterized sites in Tuscany (Italy). Soil characterization has been done in the framework of a program supported by the Regional Government of Tuscany and devoted to the assessment of local site effects and to the reduction of seismic risk. Reference spectra have been selected according to the type of soil and expected Magnitude. Influence of the variability of soil properties and input motion on the response spectra is considered. Identification of the type of soil has been accomplished by means of both shear wave velocity profile (Vs30) and penetration test results (Nspt). The relevant prescriptions of recently established Italian codes (OPCM-3274/2003, Norme Tecniche per le Costruzioni 2005), which represent a partial implementation of EC8 in Italy, are also discussed.