Homogenization of masonry vault bridges: Sensitivity to external stone arch

This paper studies the sensitivity of the structural behaviour of masonry arch bridges to the presence of external stone arch rings. European railways networks include more than one hundred thousand masonry arch bridges, which belong to two typologies: (i) the arch ring may be made in stone voussoirs and the arch barrel in brickwork masonry or otherwise (ii) the whole arch barrel may be made of brickwork masonry. A comparison between these two different structural forms is here proposed. The study, reported in this paper, considers the historical masonry arch bridge that connects Venice with the mainland, which belongs to the second typology. Two finite element models of the bridge have been prepared: The former representing the actual configuration of the bridge and the latter assuming the presence of two external stone arch rings. The arch barrel of the bridge has been modelled by means of a homogenization procedure, as well as the hypothetic configuration with the external stone arch rings. A linear analysis with a multi-scale approach has been carried out to investigate the behaviour of bridge under service loads. The more consistent conclusion of this research is that the presence of external stone arch rings may influence the structural behaviour and the load bearing capacity of masonry arch bridges, improving the performance of the bridge.