Design of a submerged floating tunnel with a free span of 1750 m

Abutment-anchored submerged floating tunnels (SFTs) are probably the most economic permanent link across deep Norwegian fjords of over 800m width. This paper describes a two-lane abutment-anchored SFT with a span of 1.75 km. The SFT will probably have harmless in-line vibrations with a period of oscillation of -100 sec. The frequency is influenced by the axial force in the tube. The change in frequency can be used to monitor the change in the deadweight of the SFT. This change can be counteracted by altering the ballast in the SFT. If there are no in-line vibrations, the SFT can be set in motion. Uneven deflection of the SFT, without traffic load, can be counteracted by redistribution of ballast. The SFT in this paper will be analyzed in the deflected state, and the results of the calculations will be available at the symposium in Alesund.