La Reale Viaduct Collapse: A Lesson to Improve the Effectiveness of Inspections of Segmental Post-tensioned Bridges and Viaducts

Due to recent events, the vulnerability of the Italian infrastructural system has become a topic of strong interest from a scientific point of view. This research work concerns the analysis of the causes that led to the collapse of a span of the La Reale viaduct in Piedmont region of Italy. The collapse occurred because of the deterioration of the prestressing cables linked to an advanced corrosive state, which resulted in a reduction in the prestressing action, causing a fragile failure of the deck. However, this significant state of deterioration had not been highlighted during the various inspections by the operators, since the presence of whitish streaks on one portion of the deck and reddish on the other could not easily be connected to the type of phenomenon taking place. The results presented in this study allow to associate the symptoms present in this structure with the collapse that has occurred, proposing two new items to be added to the defect sheets for the evaluation of the degradation of this type of structures.