Seismic Soil–Structure Interaction of Three Historical Buildings at the University of Catania (Sicily, Italy)

This study aimed to evaluate the soil–structure interaction of three historical buildings at the University of Catania using ambient noise. The results point out the different oscillation modes of Villa Cerami and Palazzo Boscarino buildings sharing a side. They also show different damping values, which are probably linked to the different rigidities of the structures, since one is a masonry building and the other is a reinforced concrete building without earthquake-resistant design. Villa Zingali Tetto, a reinforced concrete building without earthquake-resistant design, showed significant torsional effects, which may be related to the geometrical and material irregularities of the structure. Comparison of the buildings’ fundamental periods and site frequencies did not show potential soil–structure resonance effects. Modelling of the local seismic response confirms the obtained experimental site frequencies, suggesting that there are no important amplification factors. On the other hand, from both of the computed Spectral and Peak Ground Accelerations for an Mw 7.3 earthquake, intensity values were estimated for which Villa Cerami could suffer heavy structural damage, and Palazzo Boscarino and Villa Zingali Tetto very heavy non-structural damage. Additional engineering investigations, aimed at reducing seismic vulnerability, are necessary to improve the safety of these heritage buildings considering they are also used for educational purposes.