Multidisciplinary design of the new Sangro Bridge. A review of the geological, geotechnical and hydraulic issues

The collapse of the old Sangro Bridge, due to foundation scouring in the fall of 2004, caused the interruption of the national road SS16 “Adriatica” and a major disruption to the economy of this southern part of Abruzzo. Given the strategic importance of this infrastructure, the design of the new crossing has been carried out, from the very early stages, by a multidisciplinary team of structural, geological,geotechnical and hydraulic engineers. The design of the new structure could therefore be based on a sound and detailed analysis of the causes that lead to the collapse of the old bridge. This analysis spanned from geological and geotechnical aspects to hydraulic and maritime studies involving the coastline evolution over the last few centuries. Sharing their knowledge and perspectives, the team set the basic principles and guidelines to be used in the design of the new bridge. Among them, a substantial improvement of the river bed, banks and mouth, suffering from various harmful human interventions perpetrated over the last century, was deemed indispensable for the new bridge and the surrounding environment. A beneficial effect of the integrated approach to design and work supervision also allowed to minimize cost and construction time. The bridge was built in 7 months only, a time frame unheard of in the Italian infrastructure sector.