Dynamic Behavior of a Medieval Masonry Bell Tower. II: Measurement and Modeling of the Tower Motion

Abstract

The work described herein was conducted within the framework of an ongoing research program on the dynamic behavior of the Tower of Matilde, the bell tower of the Cathedral of San Miniato, Pisa, Italy, an interesting case study for its current structural arrangement and the modifications it has undergone over the centuries. This is Part 2 of a more extensive publication dealing with the results of such research and presents the experimental measurements and analyses conducted in order to determine the motion of the tower subjected to the actions produced by the motion of the two largest of its six bells. The numerical and analytical models adopted to interpret the experimental results, from the most elaborate and complex to the simplest ones, have all confirmed that the third harmonic frequency of oscillation of the largest bell is very close to the first eigenfrequency of the bell tower structure. Such studies moreover have enabled making a first approximation of the values of the global mechanical parameters characterizing the tower’s dynamic behavior.