Simplified seismic assessment of eight historical masonry towers in the North-East of Italy

During the last decades, the safeguard of historical masonry structures has become paramount, especially for all the technicians involved in the protection of the built heritage against earthquakes. In many European countries, such as Italy, which are prone to earthquakes the protection of the national heritage is of strategic importance. In this context, the seismic vulnerability assessment of eight historical masonry towers, mainly built during the medieval age and located in the North-East region of Italy, is carried out by means of simplified approaches. Three-dimensional finite element models of the eight towers are created on the basis of geometrical data deduced from both existing available documentation and in-situ surveys. Preliminary eigen-frequency analyses are performed in order to obtain some basic information about the structural behavior of the different towers. Then, a simplified approach based on non-linear static pushover analyses is adopted for the seismic verification of the global performance of the eight towers. Numerical results provide useful hints into a more accurate understanding of the behavior of such type of structures under horizontal loads, especially in relation to some geometrical features, such as slenderness, thickness of the perimeter walls, cross-section area, presence of perforations, internal vaults and irregularities in general.