Geometry as Matrix of Construction of Roman Stone Bridges: The Augustus Bridge at Narni

Abstract

The study of ancient Roman bridges embraces various disciplines and professions: engineers, architects, historians, archaeologists, and geologists. One of the first experiments completed by this research group was conducted on the Augustus Bridge at Narni: an integrated digital survey followed by the application of 3D digital modelling. Although only one of its four arches has been preserved, it can still be seen that the bridge was conceived on a large scale of technical complexity based on a precise knowledge that guided the choice of materials and architectonic solutions. The structure is immersed in an enchanting green landscape, which has for centuries attracted numerous scholars and artists. They have left us a precious iconographic heritage whose interpretation is still debated. As far as the geometry and proportions of the construction are concerned, to compare its present state with the original one, the structural ashlars of the bridge were modelled parametrically on the basis of transforming elementary geometric elements having adopted the Roman foot as the unit of measure.