PSI - Issue 84

L. Fieno et al. / Procedia Structural Integrity 84 (2026) 1127–1135

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a state of compression under no traffic conditions. No significant deterioration was observed in the remaining structural components. To achieve the Operational classification under the LLGG20 framework, the proposed measures involve hanger replacement, strengthening and rehabilitation of the tie beams, deck slab and cross beams, as well as the introduction of longitudinal and transverse prestressing.

Figure 10: Corroded hangers at the arch anchorage and proposed replacement of all hangers with new full locked coil steel cables;

The second structure dates back to the first two decades of the twentieth century. In this case, the hangers are vertically arranged and constructed of reinforced concrete with a rectangular cross-section. The bridge was built between 1913 and 1917 by the Italian company Ferrobeton and opened to traffic on May 1, 1917. Entirely constructed in reinforced concrete, the bridge has a total length of 133 m and a deck width of 9.2 m, with a 6.8 m carriageway and two 1.2 m sidewalks. The deck is approximately 8 m above the average river water level. The structure consists of three simply supported tied-arch spans, each about 44 m long (pier to pier). Each span includes two parabolic arches with horizontal thrust balanced by reinforced concrete tie beams. The deck adopts a beam-and-crossbeam scheme, with longitudinal tie beams, stringers, and transverse beams supporting a 14 cm thick concrete slab. The slab has been progressively overlaid over time, resulting in significant additional thickness. The deck is suspended from the arches by 16 reinforced concrete hangers per side. Upper transverse beams connect the arches, forming frame systems with the hangers and cross beams. Longitudinal post-tensioning strands provide precompression along the tie beams. The substructure consists of two river piers and two abutments founded on Considère-type piles. Erosion affecting one pier foundation was mitigated through targeted intervention in 2013. Over its service life, the bridge has undergone several maintenance works, including concrete repairs, reinforcement restoration, crack sealing, and full pavement replacement.