Automated Operational Modal Analysis of two nearby, short-span highway viaducts

In the context of assessing the structural condition of critical points along a portion of an urban highway in Italy, accelerometric recordings from two spans of nearby viaducts are currently being used for continuous, long-term structural health monitoring (SHM). The accelerometer layout enables vibration-based monitoring through output-only modal identification of the decks of the prestressed reinforced concrete viaducts under study, which are representative of a common short-tomedium span bridge typology in the national highway network. Dynamic identification was performed using a custom-made, recently introduced Automated Operational Modal Analysis (AOMA) algorithm. The procedure was performed using the SSI-DATA algorithm integrated with DBSCAN clustering analysis to automate the extraction of modal parameters (i.e., natural frequencies, damping ratios, and mode shapes). These results will serve as a reference for the ongoing continuous monitoring of this strategic infrastructure within a highly trafficked road network.