Advanced Seismic Assessment of Four Masonry Bell Towers in Italy after Operation Modal Analysis (OMA) Identification

The paper presents an advanced seismic assessment of four masonry bell towers located in Northern Italy based on detailed 3D FE models on which elastic parameters were previously identified by operational modal analysis. The numerical assessment includes a preliminary identification of the elastic moduli of the different volumes of each tower made by means of a fast-micro-GA approach. After proper identification of the main four eigenfrequencies, non-linear static (pushover) and full non-linear dynamic analyses are performed adopting a material model for masonry which is characterized by softening and two distinct damage parameters in both tension and compression. The results obtained with non-linear static and non-linear dynamic analyses in all the simulations performed exhibit a satisfactory match, suggesting similar conclusions in terms of general dynamic response and seismic vulnerability of the towers.