Decoding the Dynamic Behavior of Twin Church Bell Towers Through Ambient Vibration Analysis

Italy is home to numerous monumental structures of great historical and architectural value that require preservation. To ensure their protection, it is crucial to adopt minimally invasive yet effective techniques capable of assessing their current structural performance and monitoring their health. Among the most suitable methods is ambient vibration monitoring, which analyzes accelerometric recordings under operational conditions to determine the dynamic properties of the structure. This study presents the results of short-term monitoring conducted on the two towers of the San Francesco church in Ascoli Piceno. Modal identification allowed for the determination of frequencies, mode shapes, and damping ratios. These data were then used to calibrate the Finite Element Model of the complex by adjusting the elastic parameters of the masonry, aligning the numerical mode shapes and frequencies with the experimental results.