Time series models for cultural heritage preservation: the case of the Brunelleschi's Dome

In an effort to preserve the cathedral of Santa Maria del Fiore in Florence, one of the greatest monument of the Reinassance, this study investigates the impact of environmental variables on the evolution of individual masonry cracks present on the whole structure of its Dome. First cracks appeared since the late 17th century and were immediately the object of a careful monitoring activity, which led, in 1988, to the installation of a wide electronic monitoring system consisting of numerous sensors, including deformometers that detect changes in cracks width several times a day. Exploiting the data collected by this monitoring system, we explore the potentialities of time series models, in particular ARIMA models and Structural VAR models, to gather insights on the interconnections between cracks as well as on the dynamic response over time of cracks to exogenous thermal shocks. We find a negative relationship between cracks width and humidity and consistent patterns across the Dome structure for the relationship between cracks and masonry temperature that corroborates previous findings in the literature. We also provide novel evidence of differing responses to masonry temperature changes between even and odd webs and between the inner and outer domes.