Data Analysis for Heritage Structures: The Monitoring System of the Dome of Santa Maria Del Fiore

The Dome of Santa Maria del Fiore in Florence, designed by Filippo Brunelleschi, is one of the most remarkable architectural achievements of the Renaissance. Since its completion in 1436, it has been subject to natural age-ing, environmental effects, and occasional seismic events. A crack pattern was present before its first historically record in 1639 and has evolved in time, prompt-ing numerous studies on its structural behaviour and long-term preservation. The structural health monitoring of the Dome started in the 1950s, developing in the 80s with the installation of a large system of displacement transducers and ther-mometers and a smaller system of accelerometers in 2018, making it one of the longest-monitored cultural heritage structures in the world. This study revisits the long-term static monitoring dataset of the Dome of Santa Maria del Fiore in Florence to assess structural behaviour over a 10-year continuous window (2008–2018). Building on earlier analyses conducted in the 1990s, exploratory data analysis (EDA) techniques were applied to investigate seasonal and long-term trends in crack width and temperature measurements. Sensors were analysed by spatial alignment (radial, meridian, parallel), revealing consistent seasonal cycles, and thermal lag across masonry layers in the transversal section. Auto-correlation and cross-correlation functions were used to quantify temporal dependencies, highlighting the effects of thermal inertia and structural discontinuities. A least-squares double harmonic model with linear drift was fitted to crack width variation data to identify the presence of a long-term trend.