PSI - Issue 84

Donato Fiore et al. / Procedia Structural Integrity 84 (2026) 417–424

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frequencies, and vibration amplitude (Fig. 5) as shown by Fiore et al. (2024), Mazzanti (2011), Pieraccini et al. (2006), Riedel et al. (2011), and Rödelsperger (2011). Data acquisition is generally conducted with a sampling rate of 100 Hz during regular road or rail traffic to observe the structure's response under real conditions. To increase spatial coverage, the IBIS-FS system can be positioned at different angles (e.g. 30° and 90°), enabling a broader mapping of the deck's movements.

Fig. 5. (a) real time displacement (90°) for some range bin; (b) Vibration frequencies in terms of amplitude (b) and phase (c).

Thanks to the interferometric measurements, it is possible to identify the main frequencies and the real time displacement of the bridge: thus, it is useful to determine the optimal locations of the triaxial accelerometers (Fig. 6).

Fig. 6. Triaxial accelerations placement. For this SHM study, SHM accelerometers from Move Solutions were used. The SHM accelerometer is a wireless sensor designed to measure the triaxial acceleration of the installation point, which is essential to obtain vibration frequencies and carry out a modal study of the structure. The distinctive feature of these sensors is the ability to be wirelessly synchronized to other accelerometers, with an accuracy of ±500 μs. In fact, inaccurate synchronization between sensors can lead to significant errors in estimating modal parameters, especially in modal shapes. The sensors