Equivalent modal parameters in monitored buildings during the recent Italian seismic events

This paper investigates the dynamic response of a real-scale masonry building structure severely damaged during the recent 2016 Central Italy seismic events. The building is the Visso (MC) school, and the analysed data are those collected during both main shocks and minor shakings by the Seismic Observatory for Structures (OSS), the network for the permanent seismic monitoring of strategic structures, managed by the Italian Department of Civil Protection. The dynamic response data of the building are analysed through an input-output linear modal identification technique based on the N4SID algorithm. The adopted methodology is the same recently applied to analyse data trends obtained in terms of equivalent modal parameters and damping ratios, from three OSS network buildings subjected to the 2013 Lunigiana–Garfagnana seismic swarm. The investigation highlights the limitations of standard input-output stochastic subspace identification techniques in analysing the seismic response of severely damaged buildings monitored under intense shaking levels.