PSI - Issue 84

Marco Civera et al. / Procedia Structural Integrity 84 (2026) 49–56

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Keywords: Bridge Monitoring; Structural Retrofit; Half-Joints; Remote Sensing; Structural Health Monitoring; Satellite Interferometry.

1. Introduction. The Amedeo VIII Bridge (Fig. 1) represents a typical example of early 20th-century reinforced concrete (R.C.) infrastructure. A significant urban bridge, its original project was designed by Ezio Peretti and constructed by the company Ing. Giovanni Defilippi Torino between 1931 and 1933, connecting Turin, the regional capital of Piedmont, to the nearby Settimo Torinese, a large industrial area on the East side of the Stura di Lanzo River. After the bridge construction, static load tests were performed on July 9, 1936. For more than 60 years, the bridge remained operative before undergoing extraordinary maintenance works in 1998. Then, an extensive campaign of surveys and destructive and non-destructive tests was performed, including core drilling at 10 distinct locations (32 samples in total), carbonation depth measurements on the extracted cores, mapping of visible deterioration, endoscopic inspections, and photographic surveys of exposed reinforcement. The outcomes, described in an internal technical report (Formento, 2000), highlighted several symptoms of structural degradation on the superstructure, especially severe spalling and widespread cracking of counter-slabs, as well as corrosion of the exposed stirrups and longitudinal rebars. Instead, piers and abutments were found to be generally in good condition. For these reasons, the bridge was deemed to be retrofitted with external prestressing and other interventions. These were first planned in 2007, then revised and executed between January 2009 and April 2010 for the South half carriageway and between June 2010 and April 2011 for the remaining parts. A new set of structural tests was performed in 2011, including static truck load tests (six 4-axle trucks, ~420 kN each), tendon testing, and laboratory tests on construction materials, which fully validated the retrofit effectiveness. The bridge has been periodically surveyed since then.

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Fig. 1. (a) Location of the Amedeo VIII bridge (coordinates 45.098408°N, 7.721662°E), crossing the Stura di Lanzo, a major tributary of the Po River (b) View of the bridge from downstream, Settimo side.

Nowadays, almost a century after its inauguration, the bridge remains a vital infrastructure element in Turin’s transportation network, carrying an estimated average daily traffic (ADT) of 2,163 vehicles per day, which makes it a strategic infrastructure according to the local authorities. The bridge is not considered particularly at risk; according to the current Italian guidelines (Consiglio Superiore dei Lavori Pubblici - CSLP, 2020),the overall “Classe di Attenzione” (risk classification) is 4 (medium-low). Nevertheless, due to its age, traffic load, and peculiar design features (which will be detailed later), continuous structural assessment and health monitoring are critical for the preservation of this infrastructure. In this context, the ISABHEL consortium (Integrated SAtellite and ground-based monitoring for Bridge HEalth Lifetime assessment) has been appointed to develop and deploy two tailor-made Structural Health Monitoring (SHM) systems, one for this case study and a similar one for a nearby bridge, the Regina Margherita, fully described in a companion paper (Civera et al., 2025). The consortium includes the Politecnico di Torino, Nplus S.r.l., S2R S.r.l, and is led by Nhazca S.r.l. (Costantini et al., 2025). Importantly, the SHM system design encompasses not only the hardware (i.e., the specific sensing devices) but also the software required for data analysis.