Free-Field Seismic Response Analysis

Abstract

This paper shows the results of free-field seismic response analyses (SRA), that were performed for the subsoil conditions of Piazza dei Miracoli in Pisa. The site investigation and in particular the shear wave velocity profile is extended down to 120 m below the ground level. One-dimensional SRA were carried out by using three computer codes, EERA, STRATA and ONDA. The first two codes perform the analyses in the frequency domain considering a linear-equivalent soil model. ONDA analyses the problem in the time domain assuming a true non-linear soil behaviour. In particular, the Ramberg-Osgood constitutive model, coupled with a modified Masing criterion was assumed. The computed elastic response spectra were compared to those prescribed by the Italian Building Code, which represents the Italian implementation of Eurocodes. Some details concerning the response spectra prescribed by Italian Building Code are also given.