Safety of infrastructures: A case study

Recent events of bridge collapses, namely in Genoa (Italy) on August 14th 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. This work is focused on the study of the collapse of the Morandi bridge in Genoa. Based on the survey of available data from the local authorities, a preliminary analysis of the materials and loading conditions on the bridge was conducted in this study. Based on the preliminary analysis of data, the study finds that corrosion and fatigue may have contributed to the collapse of the bridge. Both corrosion and fatigue are related to the time variable that has likely affected both the operating conditions of the bridge and its capacity. The traffic load at the time of the structural design (60’s) has certainly undergone a preponderant evolution, linked both to the evolution of transports in general (increasing in loading and traffic volume) and to the port development of the city of Genoa. The increase in level of traffic load as well as volume and the climatic Mediterranean conditions have contributed to the degradation of the bridge. In fact, the port of Genoa is one of the most important in the Mediterranean for centuries, and in particular, since the 1960s, when the city increased the capacity of its port for container ships. At the same time, it makes sense to consider how the structural materials employed in different technologies (reinforced and prestressed concrete, prestressed stays) may have been subjected to the degradation. Indeed, the effect of atmospheric agents and the proximity to the marine environment may have influenced the resistant capacity of the bridge (corrosion). Furthermore, the cyclic loading due to traffic may have fatigued the bridge. Last but not least, structural solutions for stays (e.g. saddles) and the essentially static determinate scheme may have also affected the structural response at collapse.