Dynamic analysis of the interaction between bells and masonry structures

This research show the numerical and experimental results evaluated in the Fiesole bell tower in Italy. The aim of this investigation is to increase the knowledge related to the dynamic interaction between the vibration frequencies of the bells and the dynamic behavior of the masonry tower. In particular, in this paper the numerical evaluation focuses on the bell and tower interaction, taking into account the behavior of the tower as an exempt structure. In particular, the study was divided into several phases. The first phase consisted of the geometric definition of the structure, as well as the definition of the mechanical properties of the bells. In the second phase the dynamic properties of the structural system were evaluated and the numerical model was calibrated. In the third phase, lateral restrictions of the tower were released and a parametric study of the interaction of the dynamic forces of the bells with the tower was carried out. Based on these results, the velocity ranges, and swing amplitude of the bells, which could damage the tower, were evaluated according to DIN 4178-2005. The main results show that the biggest bell should not be used for velocity values near 41.53 rpm. regardless of the swing angle. Also, for smaller bells, swing angles between 50ºand 95ºand speeds between 25-40 rpm. should be avoided.