GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.2 GNGTS 2023 Ambient Noise Deconvolution Interferometry for the structural characterization of an arch bridge: the case study of the Gravina Bridge T. Nicola 1 , P. Bojana, S. Vincenzo 1 , F. C. Ponzo 3 , R. Ditommaso 3 , M. R. Gallipoli 1 1 National Research Council of Italy (CNR-IMAA), Tito Scalo (PZ), Italy 2 National Institute of Oceanography and Applied Geophysics - OGS 3 School of Engineering, University of Basilicata, Potenza (PZ), Italy Abstract In this study, the Ambient Noise Deconvolution Interferometry (ANDI) technique and the Frequency Domain Decomposition (FDD) were used to characterize the main structural properties of the Gravina Bridge (eigenfrequencies, mode shapes and propagation velocities) using ambient vibration recordings. This bridge is located in Southern Italy, close to the city of Matera and is an 144m long arch bridge with an isolation system at the base, founded on outcropping calcarenites. The structural characterization was evaluated by two measurement campaigns of ambient vibration recordings using ten sensors (five on the bridge and five inside the arch). The estimation of the main eigenfrequencies and mode shapes was done by modal analysis using the FDD method. The interferometric seismic approach was also applied to evaluate the deconvolved wave fields and estimate wave propagation velocities along the main directions of the deck. The use of both approaches, ANDI and standard OMA-based SHM approaches, facilitated the detailed interpretation of the results. The approaches proved to be very robust in estimating key structural parameters of the Gravina Bridge and were easy to apply by using short-duration ambient noise signals recorded by non-invasive and low-cost sensors without blocking the traffic flow or affecting the use of the bridge. These approaches are promising not only for the structural characterization of an infrastructure, but also for the evaluation of the variation of eigenfrequencies, mode shapes and propagation velocities of ambient noise waves as a result of aging, degradation, and/or occurrence of potential damage. Keywords: Ambient vibrations measurements · Ambient Noise Deconvolution Interferometry · Wave propagation analysis · Bridges · Structural characterization e-mail: nicola.tragni@imaa.cnr.it