Numerical modelling of the seismic response of a tunnel-soil-aboveground building system in Catania (Italy).

Seismic design of structures is commonly performed by using design spectra by national technical codes or, in some ‘‘advanced’’ designs, by using design acceleration time-histories given by 1D free-field soil response analyses. These procedures can lead to erroneous evaluations of the ‘‘real’’ inputs, which hit aboveground and underground structures due to complex interactions involving the soil and the structures. Great attention has recently been devoted to separated tunnel–soil interaction analyses and soil-aboveground structure interaction analyses. Analyses involving tunnel–soil–aboveground structures (full-coupled systems) are still very rare. The present paper deals with the dynamic interaction that occurs between a tunnel, the soil and an aboveground building, it also investigates the effects of the tunnel on the response of the soil and/or of the building and vice versa. The study has been performed using full-coupled FEM modelling. A casehistory of the Catania (Italy) underground network has been analysed. A cross-section of the underground network in Catania including an aboveground building has been modelled, by studying its behaviour during the expected scenario earthquake (MS = 7.0–7.4). The authors have investigated the seismic behaviour of the system in terms of acceleration time-histories, amplification ratios, Fourier amplitude spectra, as well as seismic bending moments and axial forces of the tunnel lining