EXPERIMENTAL AND NUMERICAL INVESTIGATIONS ON THE SEISMIC BEHAVIOUR OF THE SAN FREDIANO BELL TOWER IN LUCCA

This paper presents a study on the seismic response of the San Frediano bell tower in Lucca. The tower's ambient vibrations were continuously monitored for about one year, from October 2015 to October 2016. During this monitoring campaign, many seismic events were recorded on the tower and the most relevant turned out to be the Amatrice earthquake, which struck Central Italy on 24 August 2016. The paper begins with a review of the experimental results obtained. Then, a finite element numerical model of the tower is presented and validated via model updating, by assuming the tower's constituent materials to be unable to withstand tensile stresses. The experimental records of the Amatrice earthquake are also included in the analysis to assess the dynamic behaviour of the finite element model under ambient vibrations. Finally, a numerical simulation is performed of the tower subjected to the Lunigiana earthquake, recorded in Fivizzano (Tuscany) on 21 June 2013: the results of the dynamic analysis are presented and discussed.