Peak Displacement Response Induced by Bell-Swinging on the Masonry Tower in Castel San Pietro Terme, Bologna

The dynamic identification of masonry bell towers has been deeply investigated in the literature, mainly targeting the effect of seismic actions on the structures. However, new research horizons are still to be widened in terms of the interaction between the bell-swinging system and the structure itself, and specifically in terms of simplified experimentally-based methods that can be adopted by practitioners for the structural assessment and possible strengthening interventions on such towers. Indeed, the motion and the excitation forces, generated by the activation of the tower carillon, are often responsible for resonance phenomena causing high amplitude dynamic vibrations in slender structures which may trigger the development of structural vulnerabilities. This paper analyses the data collected during an experimental campaign investigating the effect of different bell-loading conditions on the historical masonry bell tower in Castel San Pietro (Bologna, Italy). The research proposes an original simplified method to take into account the dynamic response of the structure by extracting, from the displacement time histories, equivalent static displacement fields to be implemented inside a manually calibrated finite element model. The results show useful indications for the design of strengthening interventions.