Art and Technique of Roman Bridges.The Augustus Bridge in Narni.

Along the Via Flaminia, one of the main crossing roads of Umbria, near the town of Narni, Augustus built a bridge to cross the Nera Valley, a huge engineering work, one of the greatest masonry works built by the Romans, with four arches of which one stili intact.The archaeological site,after more than 2000 years, keeps unchanged the relationship with the city of Narni, the Nera valley and the entire valley of Temi. From the 800 until the Second World War this area has undergone signifìcant modifications. The Augustus bridge in Narni is being studied for centuries, from Renaissance onwards. In recent times, several engineers surveyed the bridge, with the primary objective of consolidating the existing structures in order to prevent further instabilities and collapses. Some of them have also hypothesized the originai confìguration and the changes occurred over time. ln 2015, our research group has made a new survey with laser scan digital technologies integrated with photogrammetry, broadening the area of the previous surveys. The survey elaborations have allowed to formulate new hypotheses on the conformation of the four arches of the bridge and on the location of the ancient Via Flaminia. Another aspect of the contribution relates to the identification of the potential of 3D modeling in the new digitai modes of communication of the cultural heritages. lt can thus promote new forms of dissemination and knowledge to a diverse audience, showing how, in this case,the building technique can rise to real art, respecting of the landscape