Submerged Floating Tunnels under Seismic and Seaquake Loadings

Submerged Floating Tunnels (SFTs), also named Archimedes Bridges, are a promising alternative to cross a water body. SFTs are normally designed with positive buoyancy, and are held floating underwater by a mooring system anchored at the seabed. In the case of an earthquake, SFTs will have to withstand both the effects of ground motion at the supports as well as the so-called “seaquake” loading. This last is due to the transmission through water of compressive waves originated by the seabed motion. The studies on seaquakes are contrasting with respect to the effects of the compressibility of the soil below the seabed. In this light, this paper extends the model for generating seaquake effects, set-up by the research group, by including this aspect. A first comparison of the loading due to seaquake with and without the presence of a compressible soil layer is carried out for a significant prototype structure