Operational Modal Analysis of a Heritage Masonry Building in Naples

This study investigates the dynamic behaviour of the former military hospital, a heritage masonry building located in Naples, Italy. Ambient Vibration testing (AVT) coupled to Operational Modal Analysis (OMA) represents a powerful experimental methodology for the structural assessment of masonry constructions, as it enables the calibration of numerical models and, in some cases, the identification of potential damage states. Nevertheless, its practical implementation on masonry heritage is often constrained by the limitations of conventional experimental setups, especially in the case of large buildings and a limited number of available sensors. In this research, multi-setup ambient vibration testing is complemented by non-destructive sonic tests to capture the dynamic response of the structure and the masonry material parameters. The corresponding modal parameters (namely, natural frequencies and mode shapes) are estimated from the recorded vibration data through Frequency Domain Decomposition (FDD) and used to calibrate a finite element model of the building through a model updating analysis. The adopted methodology allowed for a strong correlation between the experimental and numerical dynamic properties. The findings provided a comprehensive understanding of the building’s seismic behaviour and potential vulnerabilities, thereby establishing a robust analytical basis for assessing the building's vulnerability against natural events and implementing effective retrofitting and preservation strategies for heritage masonry buildings.