Il viadotto sul torrente Polcevera a Genova (1959-2018). Cronistoria di un crollo

The Viaduct over the Polcevera River in Genoa (1959-2018). Chronicle of a Collapse After the tragic collapse of a section of the viaduct on 14 August 2018, the demolition of the entire Bridge over the Polcevera River in Genoa has started. The bridge is a work of Riccardo Morandi, one of the most important bridge designers of the XX century in Italy and worldwide. The exceptionality of this work relies on the outstanding technical knowledge and engineering innovation displayed by that bridge despite the economic and political crisis affecting Italy since after the end of World War II. The ability of shaping sophisticated piece of structural engineering with a craft approach, forced by industrial underdevelopment in the Italian construction sector, is a common feature of the modus operandi of the Italian engineers at that time. The construction of the Autostrada Del Sole, the buildings for the Olimpic Games of Rome 1960 and for the Exposition of Turin 1961, are eloquent examples of such approach. The fame of these unique architectural or infrastructural products is due to their originality and technical audacity despite the use of traditional construction techniques. We, therefore, need to investigate in depth the story behind these masterpieces in order to preserve them as pieces of our recent heritage. Sadly, many of these infrastructures suffer today of severe degradation, showing signs of materials decay. These unexpected ageing manifestations are due to several factors: the pioneering design principles of the structures, the level of air-pollution that lately has become particularly aggressive, the traffic conditions overtaking the past structural loads, and the lack of adequate maintenance. Following the tragic event in Genoa, newspapers in Italy have blamed the structural designer conveying a wrong message throwing unfounded accuses against the project and Morandi himself. For this reason today is important to retrace and narrate the epical history behind the technical development of this innovative masterpiece giving back the right credit to the designer. The project started in 1959 when Anas launched a national competition by invitation for the 24th lot of the Genoa-Savona motorway. 2400-meter-long, it included even the viaduct on the river Polcevera. The competition documents define road layout and sections. Instead, the position of the viaduct pylons is determined by the dense urbanization in the underlying area and, above all, by the presence of a railway park, whose functioning must be guaranteed.