Bell Tower Dynamic Motion: Latest Research

Presentation delivered by Gordon Breeze on Wednesday 3 February 2021.

The primary motivation behind the work described in this talk relates to bell handling. When ringing bells generate large horizontal peak forces, and these forces set the bell tower into dynamic motion. The handling of bells depends upon the magnitude of the bell tower motion. A great deal of theoretical study has been undertaken into the forces generated by bells. There are text books that consider from a theoretical standpoint the dynamic motion of structures and buildings. Nevertheless, it is only by bringing these two matters together that a bell tower motion can be predicted when a bell (or bells) is being rung.

This talk describes testing that was recently undertaken at Wingrave Church. Dynamic testing was undertaken with a rotary shaker; this testing is the industry-standard approach to determining the dynamic structural characteristics of buildings and structures. At a peal-ringing speed, the theoretical horizontal forces of the 8 Bell (tenor) were combined with these dynamic characteristics to predict the response of the tower. This predicted tower response is compared with the actual measured response – the results and findings are presented in the talk.

The rotary shaker is a specialised piece of test equipment, and so a natural question is: can the bells themselves be used to determine the dynamic characteristics of a bell tower? Watch the talk for the unequivocal answer.

Click to download slides: Bell Tower Dynamic Motion: Latest Research (PDF – 1.42MB)