Dynamic Assessment of Cultural Heritage Structures via Ambient Vibrations: A Bell Tower Case Study

Ambient vibration-based Structural Health Monitoring (SHM) is increasingly employed to assess the dynamic characteristics of structures, such as fundamental frequencies, damping ratios, and modal shapes. Operational Modal Analysis (OMA) techniques are particularly advantageous due to their cost-efficiency and non-invasive nature, allowing monitoring under operational conditions without requiring artificial excitation. This study proposes an OMA technique resorting to the Hilbert transform able to streamline the dynamic identification of a structural system in a few concise steps. The efficiency of the proposed method is demonstrated through its application to a real-world masonry bell tower, part of the Church of “San Matteo al Cassaro” a notable landmark in the heart of the old town of Palermo in Italy.