Numerical Insight on the Dynamic Identification of a Reinforced Concrete Bell Tower

The dynamic identification of a reinforced concrete bell tower was investigated in this paper by analysing the case study of the tower of San Giovanni Battista church in Firenzuola (Florence, Italy). The bell tower and the church were built between 1959 and 1966 based on the project of two Italian architects, Carlo Scarpa and Edoardo Detti. Since its construction, the bell tower has shown some concerns arising from the dynamic interaction between the bells’ swinging and the tower. Currently, this phenomenon and the progression of the degradation of the reinforced concrete are leading to the necessity of conservative restoration works. The paper focused on these aspects by illustrating the results of a one-day of experimental campaign. Indeed, the integration of Structural Health Monitoring (SHM) techniques for historical structures always raises great interest in the scientific community but only a few scientific papers deal with the structural response of towers under bell-induced loads. With this aim, the signal acquisition was conducted both under ambient vibrations (wind and traffic) and under vibrations induced by the swinging of one of the five bells currently located on the tower. The results of these tests were analysed with the aim to identify natural frequencies and modal shapes.