Dynamic identification and automatic updating of the numerical model of a masonry tower

The actual dynamic behavior of the masonry civic Clock tower in a little village, heavily damaged by the recent 2016 seismic sequence of central Italy, is thoroughly investigated by means of a detailed numerical model built and calibrated using the experimental modal properties obtained through Ambient Vibration Tests. The goal is to update the uncertain parameters of the Finite Element Model (elastic moduli, mass densities, constraints, and boundary conditions) to minimize the discrepancy between experimental and numerical dynamic features. Due to the high nonlinear dependency of the objective function of this optimization problem on the aforementioned parameters, and the likely possibility to get trapped in local minima, a fully automated Finite Element Model Updating procedure based on genetic algorithms and global optimization is used, leading to the successful estimation of the uncertain parameters of the tower. The results allowed to create a reference digital replica of the current structural condition of the tower and to set the performance standards that will help to optimize the control of the structural integrity over time.