Seismic soil-structure interaction: two case studies in Sant’Agata de’ Goti, Italy

The paper deals with the results of a multidisciplinary study aimed at assessing the seismic vulnerability of two historical buildings in a picturesque medieval village in Southern Italy, taking into account the interaction among structure, soil and underground cavities. The subsoil model accounted for nonlinear visco-elastic hysteretic behavior, as calibrated on the basis of past and recent geotechnical and geophysical investigations. A strain-softening constitutive model was adopted to simulate the nonlinear behavior of masonry, according to a macro-mechanical approach. Some of mechanical parameters were calibrated against experimental data resulting from uniaxial compression tests performed on single-leaf masonry prisms. 2D nonlinear dynamic analyses were performed with the FLAC code on soil-cavity-structure models by applying a reference input motion compatible with the design acceleration spectrum specified by the Italian code of practice. The building performance and its ability to restore the pre-event conditions were respectively assessed in terms of maximum and residual lateral drifts of the main walls and foundations.