Dynamic Response of the Giotto’s Bell-Tower, Firenze, Italy

An ambient vibration survey of a structure represents an efficient and accurate technique for the characterization of its dynamic response to wind and seismic excitation. The dynamic response of the Giotto’s bell-tower has been monitored with four velocimetric stations placed along the tower. The frequencies values and modal shapes have been evaluated by analyzing the data in the frequency domain and time domain respectively. Two translational modes for each direction and a torsional mode have been detected. An iterative back-analysis procedure has been set up to define a realistic elastic modulus of the stone masonry. The soil-structure interaction has been included in the identification process. The elastic modulus of the stone masonry represents an important mechanical parameter for the definition of reliable finite element models of the structure, that could be an useful tool for further investigations on the tower seismic behavior.