Digital Twinning of Bologna's Garisenda Tower: Evaluation of Incident Solar Radiation

This thesis proposes an approach to simulate solar irradiance on the external surfaces of the Garisenda Tower in Bologna, Italy. A reliable radiation input dataset, to be used within thermo-mechanical simulations in the framework of the tower’s Digital Twin to support structural health monitoring (SHM), is generated. Thus, a year-long dataset of average incident irradiance values was generated for every point of the external surfaces of the tower, discretized into 9 m² patches. The results confirmed several expected trends, such as distinct morning and afternoon irradiance peaks on the East and West Facing Sides, respectively. Three of the four sides displayed a bell-shaped distribution with higher average incident irradiance values in summer, while the South Facing Side exhibited an inverted pattern due to the higher solar elevation during the summer months. These seasonal and daily variations were consistent with the known sun path and were validated through comparison with historical weather data. This thesis provides a tool to estimate the solar irradiance time-histories on cultural heritage monuments, and the work contributes both to the scientific understanding of irradiance on historic buildings and to the practical challenge of safeguarding the Garisenda Tower for the future.