6-Years Vibration Monitoring of the Milan Cathedral

The Milan Cathedral is the most iconic symbol of Milan and one of the largest heritage monuments ever built. Since October 2018, a monitoring system is active in the historical building with the main objective of continuously extracting and classifying features which are representative of the current state of structural health.The paper is aimed at presenting selected results from the Structural Health Monitoring of the Milan Cathedral by applying statistical pattern recognition techniques to continuously collected data during the period from 2018 to 2024. It should be noticed that: (a) the dynamic response of the structure is collected in a reasonably well distributed measurement grid (27 channels of data), so that both natural frequencies and mode shapes could be conveniently used for anomaly detection and localization; (b) the dynamic monitoring system is complemented by a static monitoring system including vibrating wire extensometers mounted on selected tie-rods as well as temperature and humidity sensors for the measurement of internal and external environmental parameters.