Design of a dynamic monitoring system for the Saint Lawrence Cathedral in Genoa, Italy

The recent collaboration between the University of Genoa and the Archaeology, Fine Arts and Landscape Superintendency of the Metropolitan City has led to the installation of a dynamic monitoring system on the Cathedral of Saint Lawrence, one of the most ancient places of worship in Genoa dating back to the 12th century. Aiming at supporting maintenance and preservation strategies, a dynamic monitoring system has been designed and installed to assess the structural health conditions of the church based on experimental vibration data. The sensor network involves diverse technological solutions: Force Balance accelerometers at the base of the church and high-sensitivity MEMS accelerometers at height, continuously measuring the operational micro-vibrations of the fabric and the seismic response to possible earthquakes. Measurements are acquired by independent acquisition nodes, synchronized via GNSS and sent to a central processing unit via cable or Wi-Fi for real-time processing, including assessment of vibration level, dynamic identification, and modal tracking. Integration with temperature data, moreover, allows capturing the effects of varying environmental conditions. The paper discusses the lessons learnt during design and installation phases, identifying the key challenges in achieving continuous data-driven structural health assessment. Preliminary ambient vibration measurements highlight a complex dynamic interaction between the church and the bell tower, with several close or fully coupled modes in the low-frequency band below 6 Hz. This test provides a baseline for choosing optimal sensor technology and, more importantly, demonstrates the feasibility of current high-end MEMS accelerometers for operational vibration monitoring and SHM of cultural heritage structures.