Dynamic Identification and Model Updating of Palazzo degli Elefanti in Catania

In monumental masonry buildings, the complexity of structural elements, non-uniform distribution of mechanical parameters, as well as orthotropic behavior can lead to discrepancies between numerical models and actual dynamic behavior. To minimize these discrepancies, experimental modal parameters can be utilized in model-updating methods. These methods involve adjusting geometric and mechanical parameters to reduce the error between actual and modeled dynamic behavior. Advances in measurement tools and operational modal analysis enable the extraction of these parameters from structural vibrations caused by ambient noise, eliminating the need for specific vibration sources. This research demonstrates the application of model-updating procedures on Palazzo degli Elefanti, a late 17th-century building in Catania, Sicily, which was partially damaged by arson in 1944 and restored in 1952. Since 2004, the building has been monitored by the Seismic Observatory of Structures within the Italian Department of Civil Protection. The study begins with the collection of vibration data from the DPC’s monitoring system. Although the initial numerical model was based on geometric surveys and mechanical tests, differences were observed between the modal parameters of the analytical model and the experimental results, particularly in the first two modes, which were originally inverted. The model-updating process began with a detailed finite element (FE) model incorporating masonry walls, vaults, concrete floors, and roofs, while accounting for variable geometric and mechanical properties. The calculation routine, developed by the University of Roma Tre and the DPC, employing SAP2000 APIs, helped to align the experimental and numerical responses, addressing the complexities inherent in monumental masonry buildings.