PSI - Issue 84

Antonella Cosentino et al. / Procedia Structural Integrity 84 (2026) 882–889

884

in Fig. 2. The bridge serves a secondary extra-urban road, consisting of a single roadway with two lanes (one for each direction), protected by metal guardrails and two side sidewalks protected by parapets that, prior of the intervention, were not walkable. The two residential areas connected by the bridge start at the bridge abutments, effectively making it an urban bridge.

Fig. 1. “La Botte” bridge prior of intervention

Fig. 2. Geometrical schemes

The bridge is characterized by the presence of Gerber-type supports. These construction details, widely used in the past, have proven to be particularly vulnerable to degradation over time due to water infiltration that easily occurs from the joints and the impossibility of a complete inspection. Furthermore, as deep elements, they have a brittle shear failure mechanism, which is therefore difficult to predict; this makes them structural elements to be monitored with particular care. Some degradation phenomena of the Gerber supports were also evident on the bridge under study. Fig. 3 shows the presence of extensive areas affected by active and passive humidity phenomena and drainage traces. The presence of an advanced state of degradation and the strategic role of the bridge serving a highly busy road made it necessary to perform a safety assessment in accordance with the Ministerial Guidelines to estimate the effective load bearing capacity of the structural elements.