Author
C. GENTILE, A. SAISI and L. BINDA Department of Structural Engineering, Politecnico di Milano, Milan, Italy

Abstract
The dynamic characteristics of an historic masonry bell tower are investigated using full-scale testing and finite element analysis. The tower, about 74m high, is adjacent to the Cathedral of Monza (Italy) and exhibits major cracks on the western and eastern load-bearing walls. The experimental program includes ambient vibration tests of the tower; full details of the dynamic experimental procedures, instrumentation and data analysis techniques are reported. In the theoretical study, vibration modes were determined by using a 3D finite element model. The comparison between measured and predicted modal parameters was then used to verify the assumptions adopted in formulating the model. Specifically, a good match between theoretical and experimental modal parameters was reached for relatively low stiffness ratios of the model in the zones of the Tower which were most damaged.