This report illustrates the outcome of the submerged floating tunnel (SFT) Analysis Project, carried out by the Danish Road Institute, the Norwegian Road Research Laboratory and the Italian company Ponte di Archimede nello Stretto di Messina Spa, with financial support by the European Union. SFT is a tube-like structure, floating at some depth below the water surface and fixed (and/or moored) against excessive movements. The tube is designed to accommodate road and/or rail traffic. The main components of SFT are: tube, anchoring and shore connections. In principle SFT can be considered for all waterway crossings; in practice, they are of major interest especailly where gentle gradients and/or low environmental impact are important. Although no SFT has been built up to now, several studies have been carried out world-wide. The most significant are: the Hoesfjord crossing, in Norway; the Messina Straits crossing, in Italy; and the Northern Japan Exchange Axis. Presently SFT are not covered by any specific offical regulations, assessed at international level. Existing studies have been developed on the basis of a combination of existing codified rules for land based bridges and tunnels and existing rules for offshore structures, supplemented by a set of design guidelines, developed `ad hoc' for each project. The report covers the following topics: (1) the basic concepts of SFT technology; (2) the most relevant benefits of SFT and some indication of the costs; (3) the main topics related to design, construction and operation of SFT (with particular reference to: hydrodynamic load and response, seismic load and response, tethering and anchoring, construction and installation, equipment and maintenance); (4) the basic issues related to safety and environmental impact, and (5) the current position on existing regulations and standards.
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