Remarks on the collapse of the Polcevera viaduct

In recent years several studies have been developed on structural collapses oi buildings, leaving the bridges' field partially investigated by few researchers. However, recent events of bridge collapses, namely in Genoa (Italy) on August 14t h 2018 and in Kolkata (India) on September 4th 2018, have focused the public interest on the infrastructures' safety for their consequences in terms of fatalities and injuries, but also of economy and social losses. The present work is focused on the disproportionate collapse of the Morandi's Bridge in Genoa and consists in an independent study that is based on the available data from literature. The possible triggering events have been deepened starting from the corrosion and the fatigue issue of the steel tendons within the stays. Furthermore, the evolution of the loading conditions in terms of trucks' number and individual truck weight from the bridge opening (1967) is considered. Therefore, (i) corrosion and fatigue models have been selected from literature and identified through original local weather parameters as temperature, humidity, chlorides, etc. while (ii) statistical historical data of the highway traffic in Italy have been collected. They are useful in the numerical analyses with finite element models of the Morandi's bridge to identify possible collapse initiations. Some remarks on the role of redundancy in bridges structural scheme as the strategic characteristic to avoid the disproportionate collapse and to improve robustness are provided. Furthermore, the degree of static-indeterminacy of the structure with respect to disproportionate collapse is also discussed.