Issue 46

F. Bazzucchi et alii, Frattura ed Integrità Strutturale, 46 (2018) 400-421; DOI: 10.3221/IGF-ESIS.46.37 402  inadequate waterproofing covering of the joints. Figure 1 : Overview of the Petrulla viaduct (a) ; collapsed structure (b) ; original design of the deck (c,d) . Figure 2 : Steel components corrosion, strands (a) , metallic sheathing (b) ; concrete condition (c) ; unsealed vent pipes (d) . A visual inspection campaign was carried out for all the others remaining beams that constituted the Petrulla viaduct. Four level of damage degree were defined, from no noticeable damage (green) to exposed prestressing cables with visible signs of oxidation (red). In Fig. 3(a), the visual inspection location with its relative degree of damage for the bridge n. 2 has been reported. In Fig. 3(b), results for the entire viaduct have been summarized. It is worth to note that, even if less than 7% of the cases had a high degree of damage (blue and red), they represented 8 different visual inspections, which meant 8 possible beams with no active prestressing forces. This viaduct has been object of reparation and after four years has become operative again. It is reasonable to say that the investigation, repair, and public costs due to the inoperable structure are significantly higher than the ones associated with careful construction procedures. The adopted safety solutions are discussed in the next section (par 6).