PSI - Issue 84

Gianluca Centofanti et al. / Procedia Structural Integrity 84 (2026) 1339–1346

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2.2. Boccea Viaduct

The structure is part of the A90 motorway, also known as the “ Grande Raccordo Anulare ”, which functions as the ring road of Rome, and is located near Exit 2 – Via Boccea. The viaduct consists of ten continuous spans, each approximately 34.00 m long, featuring a prestressed reinforced concrete (PRC) box-girder deck, arranged along a curved alignment. The installed structural monitoring system is accelerometric and, in accordance with ANAS standard configurations, provides for the installation of three sensors, equally spaced at the quarter-span locations of the deck, at both ends of the box girder. The system is completed by accelerometers installed on the pier caps and by temperature sensors located on the odd-numbered piers. The modal analyses highlight a globally continuous structural behaviour across the entire viaduct, as expected given the adopted construction typology. For this reason, a “Whole” subgroup is defined, collecting all the vertical direction channels of the deck over the whole structure, for a total of 60 channels. This choice is supported by a perfectly diagonal MAC matrix, comprising 22 identified modes with MPC values consistently greater than 84% (see figure 4 and table 2). In addition, a “Piers” subgroup is defined, including the accelerometric sensors installed on the pier caps, aimed at the evaluation of seismic modes.

Figure 4. The Boccea Viaduct: photos, sensors position, stabilization diagram for the Whole sub-group, identified mode shapes for the Whole subgroup.