Submerged floating tunnels

Analysis of the submerged floating tunnel concept.

Following several years of development, international discussions and actual project proposals for submerged floating tunnels (SFT) ,an application was submitted on behalf of FEHRL, for a European Commission grant to support an analysis on SFT.    This project was carried out by the Danish Road Institute, the Norwegian Road Research Laboratory and the Italian company Ponte di Archimede nello Stretto di Messina S.p.a.,.

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 especially 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 Høgsfjord crossing, in Norway; the Messina Straits crossing, in Italy; and the Northern Japan Exchange Axis. The major benefit of SFT technology is related to the very low environmental impact, with reference to both landscape and pollution. Additional benefits are related to lower energy consumption (due to more gentle gradients) and to the absence of any interference with water surface traffic. SFT appears to be competitive, With respect to other water crossing solutions such as bridges and immersed tunnels, especially when the length exceeds one kilometre and the water depth exceeds 50 metres.

Main report (pdf, 2.2MB),   Annexes (pdf,5.7MB)