Structural Characterization of Infrastructures through multi-Methodological Geophysical Approach

As part of structural and infrastructure health monitoring, we propose a rapid and non-invasive experimental geophysical survey to determine the key structural parameters of an infrastructure. This approach involves the simultaneous acquisition of 20 minutes of seismic ambient noise using seismic arrays strategically placed at various points of the structure. These acquisitions do not require diverting or blocking traffic flow, nor does it disrupt the operation of road infrastructure.

The acquired signals are analyzed using various techniques, including standard spectral analysis (Fourier Amplitude Spectra, FAS), Frequency Domain Decomposition (FDD), Ambient Noise Deconvolution Seismic Interferometry (ANDI), and NonPaDAn analysis. This approach, which involves the joint application of these methods, was developed and validated on two types of viaducts: the Gravina Bridge, located on the SS.655-Bradanica, and the Monticello Viaduct on the SS.407-Basentana (Albano di Lucania), both in the Basilicata region of Italy.

The Gravina Bridge is a newly constructed arch bridge, and the structural parameters experimentally estimated are a reference point for future investigations into the evolution of these parameters over time. In contrast, the Monticello Bridge, a multi-span viaduct built in the 1970s, allowed for a comparison between the estimated structural parameters and the varying degrees of degradation observed in its girders.

By employing multiple analysis methods, the interpretation of results has been enhanced, demonstrating the potential of this approach to estimate the main vibrational modes, the relative modal shapes, equivalent damping, and seismic noise wave propagation velocities and the evolution of these parameters over time.