On site investigation and continuous dynamic monitoring of a historic tower in Mantua, Italy

The paper describes the strategy applied to assess the structural condition and the seismic vulnerability of the Gabbia tower in Mantua, after the seismic sequence of Spring 2012. The post-earthquake investigation highlighted the poor state of preservation of the upper part of the building and suggested the installation of a simple dynamic monitoring system, as a part of the health monitoring process helping the preservation of the historic structure. The results of the continuous dynamic monitoring for a period of about 15 months highlighted the effect of temperature on automatically identified natural frequencies as well as the non-reversible structural effects determined by a far-field earthquake.