The Recorded Seismic Response of the Santa Maria Di Collemaggio Basilica to Low-intensity Earthquakes

The seismic response of masonry monumental structures is a debated matter. In this paper, the authors compare the dynamic response of the Santa Maria di Collemaggio basilica under low-intensity earthquakes to the dynamic response under operational conditions. A permanent number of accelerometers records the dynamics of the Santa Maria di Collemaggio basilica under both operational and seismic excitation. It is questioned whether the earthquake intensity and the ambient parameters affect the modal parameters. The Least-Squares Complex Exponential (LSCE) method leads to the FRF function estimation. The stable frequencies identify the linear modal parameters which are likely to reproduce the seismic response. The authors endeavour to discuss whether the detected variations of the modal parameters are due to possible structural or material non-linearities. A time-frequency analysis confirms the results of the linear identification method. Further, the estimate of the dynamic amplification factors gives a glance over the global response by evidencing the possible existence of a macro-element response pattern.