Dynamic identification and seismic assessment of medieval masonry bell towers.

Most part of Mediterranean area has been classified seismic. For the new buildings a suitable code can be followed and the material and the technology can give an effective contribution to the seismic resistance of the structure. On the contrary, for the old masonry monument only a reliable structural analysis and some specific and not much invasive retrofitting can be adopted. In this context, towers are a very interesting case study because highly vulnerable to horizontal actions, but also because more emblematic to study some peculiar aspects of the material behavior. In this paper the vibration measurement, the structural identification and the seismic assessment of two Middle Age’s towers have been presented and analyzed. Compressive tests, flat jacket tests and environmental vibration measurement are used for the structural identification. Soil profile, semi-destructive test and “on site” recorded measurement, as well as preliminary historic and technical archive documentation of the monument have been collected and used in order to understand the dynamic behavior of the towers. A critic evaluation of all these results and information have been cross linked and an iterative analysis has been carried out calibrating and refining the finite element model of the structure.