Post-collapse analysis of Morandi’s Polcevera viaduct in Genoa Italy

Morandi’s Polcevera viaduct was an important transportation link that connected port of Genoa to other major cities in Europe. The bridge was in service for over 50 years and carried the traffic over one of the busiest highways in Europe. Real-time structural health monitoring would have provided data for maintenanceand warned of impending failure. The objective of the study reported herein was to estimate the remaining service life and predicting the end of life for the bridge in the absence of available sensor data. The analysis involved time-domain estimation of bridge capacity loss over the period of bridge service and increase in demand over the same period. In addition to the existing information about the bridge, combined effects of corrosion and fatigue were considered in estimating the decrease in the capacity of the bridge from the time it was placed in service. Classical influence line analysis of the individual sections of the pylon–deck system of the bridge, together with the finite element model of the bridge, provided the numerical tool for analysis of the bridge. A number of different approaches were compared in estimating the remaining life of the bridge, including the cumulative damage law of Palmgren and Miner, as well as the Goodman, Gerber and Soderberg mean fatigue stress diagrams. The predicted timing of collapse by these models ranged from the year 2014 based on the cumulative damage law, and 2016 by the Gerber and Goodman diagrams. The estimates from this study predict the collapse of the bridge 2–4 years prior to the actual collapse date in 2018. The results of this study indicated that even without an active instrumented structural health monitoring system, basic engineering principles may provide the backing for estimation of remaining life of the infrastructure. In the case of the Morandi bridge, such an analysis at some point during its service life would have possibly predicted imminence of collapse prior to the actual collapse.