On the soil-structure interaction in the seismic response of a monitored masonry school building struck by the 2016-2017 Central Italy earthquake

The paper discusses the effects of Soil-Foundation-Structure (SFS) interaction on the seismic response of the “Pietro Capuzi” school in Visso, a village located in the Marche region (Italy) that was severely damaged by the 2016-2017 Central Italy seismic sequence. The school is a two-story masonry structure founded on simple enlargements of its loadbearing walls, which are only partially embedded in the alluvial loose soil of the Nera river. The structure was moni-tored as a strategic building by the Italian Seismic Observatory of Structures. The dynamic be-havior of the school under both ambient noise and the recently occurred seismic events was interpreted and compared with numerical simulations. A 3D structural model of the school was realized according to the equivalent frame approach with addition of springs that simulate a compliant base. The spring stiffness, representing the real part of soil-foundation dynamic im-pedance, was calibrated on the soil shear modulus mobilized during the seismic excitation, in-ferred from the deconvolution up to the bedrock of the accelerogram recorded at the under-ground floor of the school. The amplitude of the acceleration and the evolution with time of the frequency resulted from the analyses of the compliant-base and fixed-base models under the three main events of the Central Italy earthquake were compared to the actual records.