Masonry bell towers: dynamic considerations

The building of masonry bell towers was customary in Europe until the beginning of the twentieth century. At the present time, most of the work carried out on these structures involves either conservation or rehabilitation, owing to their considerable historical value. One of the forces that can have an influence on the behaviour of a bell tower is that caused by the turning/oscillation of the bells themselves. This is a dynamic force and may interact with the tower's natural frequencies. This paper describes the effect of bell-ringing on masonry towers. The towers are classified and a series of data are offered to characterise their behaviour. Finally, a procedure is described that permits an assessment to be made of this type of structure.