Pietro Giaretta

ITS Inter- and Transdisciplinary Sessions

The 2024 Outstanding Student and PhD candidate Presentation (OSPP) Award is awarded to Pietro Giaretta for the poster/PICO entitled:

Bridge Failure and Consequences: the Existing Infrastructures Need of Mitigation Techniques (Giaretta, P.; Salandin, P.)

Click here to download the poster/PICO file.

Pietro Giaretta is currently a PhD student under the supervision of prof. Paolo Salandin at the University of Padova (Italy). His research focuses on the localized erosion at bridge piers and the design of countermeasures to protect existing bridges from failure, through numerical and laboratory experiments.

The awarded poster at EGU 2024 focused on the need of existing bridges of proper mitigation techniques. On May 3, 2023, the bridge of the SS 177dir that crosses the Trionto river near Longobucco (CS) collapsed during a flood event due to the localized erosion of the riverbed around one of the central piers. This was one of many cases, but it is well known that over 50% of bridge failure is related to hydraulic phenomena, and, among these, scouring around piers and abutments plays a fundamental role if proper deepening of foundation is not provided in the design. Many bridges realized in the past are characterized by foundations of limited depth. Anyway they are actually still working thanks to the ancient custom of filling any recognized scour around piers and abutments with launchable stones after each relevant flood event. Now, riprap mattresses are sometimes adopted as countermeasures instead to assume a proper deepening of foundations. The research presented compares these two techniques, launchable stones and riprap mattresses, through laboratory experiments. The findings revealed that while riprap mattresses require a lower volume of stones, leading to lower costs, they are less effective than launchable stones in protecting the bridge pier. Additionally, the failure of the Trionto bridge was compared to a similar laboratory bridge model, showing as the common technique of grouted riverbed mattress often adopted as countermeasure against scour is clearly ineffective. The stability against localized scour can only be obtained by proper deepening of foundations, since the rip-rap mattress should be adopted as a mitigation measure for existing bridges, it must be continuously monitored and maintained anyway.