Influence of geotechnical parameters and numerical modelling on local seismic response analysis

Following the new Italian Technical Standards for Constructions, in-situ tests for determining shear wave velocity profiles are performed by designers, with the aim of evaluating the local seismic response analysis of the soil. It happens, in some cases, that Vs profiles obtained with different types of investigation, performed even at close distances, give different results with each other. This inevitably involves some uncertainty on seismic response analysis. Further uncertainties arise from the different behaviour of soil non-linearity, about the de-cay of the shear modulus and the increase of the damping factor with deformation progresses. To these uncertainty factors, related to soil properties, are added the uncertainties arising from the different computational codes used for the numerical analysis. In the present work has been executed an extensive local seismic response analysis by comparing different methods of investigation for the estimation of shear wave Vs, including Seismic Dilatometer Marchetti Tests SDMTs, with particular reference to soils of Emilia Romagna (Italy), affect-ed by the earthquakes of May 20-29, 2012. For what concerns the codes for the numerical analysis, two codes that perform 1-D analysis are compared, easy to use even in professional practice: the EERA code and the STRATA code. Results of seismic response analyses ob-tained by the two codes have been compared and discussed