The design analysis of a reinforced concrete building, seismically isolated at its base by a combined system of steel-teflon sliding bearings and silicone-fluid viscous spring-dampers, is reported in this paper. The influence of the friction-like be-haviour of sliders on the global system response is initially examined, by exploiting the results of an experimental programme carried out to this aim within the European Community funded Research Project “DISPASS”. The application of a prelimi-nary design criterion, formulated in previous studies dedicated to this special protection strategy, is then presented. The damping coefficient of fluid viscous dissipaters capable of optimising the seismic response is particularly located by this cri-terion. A synthesis of the analyses developed by the finite element model of the structure is after-wards proposed. The performances obtained for the seismic action levels corresponding to the damage and ultimate limit states, according to the most recent Italian Standards (Ordinanza 3274) requirements, as well as to a third – so called maximum considered – earthquake level, are finally discussed.
