Bell's dynamic action on a historical masonry tower

it is well known that masonry bell towers are particularly susceptible to dynamic actions, including those produced by the motion of the bells themselves. The present work represents the natural follow-up to an earlier one which presented the first results regarding the dynamic behaviour of one example of such a structure, the Tower of Matilde. This bell tower of the Cathedral of San Miniato (Pisa) represents a considerably interesting case because of both its current structural morphology and the modifications it has undergone over the centuries. The previous studies suggested that the second fundamental frequency of the actions produced by the bells’ motion nearly coincides with the first natural frequency of the tower, but involved accurate experimental investigations and demanding numerical processing. The present report illustrates the results of a second, follow-up study aimed at defining a methodology for determining the resulting actions on the bell tower and the characteristic mechanical parameters of its response by using elementary analytical models that call for performing only simple, straightforward experimental tests.