A comparison study of submerged floating tunnels with vertical and inclined tethers, Arc and straight configuration under regular waves

Submerged floating tunnel (SFT) is an innovative structure to cross waterways such as straits, fjords and lakes. With the increase in width and depth of waterways, conventional structures such as cable-stayed bridges, underground tunnels or immersed tunnels become uneconomic structures. In order to properly understand the tunnel-hydrodynamic coupling behavior, this structure should be investigated under severe sea conditions and with different mooring systems and configurations. In this research, the dynamic response of SFTs with different configurations and mooring systems under regular waves has been compared. In order to obtain the dynamic responses caused by regular wave load, modeling in ABAQUS software and AQUA method has been used. The arched configuration in the SFTs reduces the range of structural responses. It has been shown that the SFT with arched configuration behaved much better than the tunnel with straight configuration. Also, from the point of view of cable mooring systems, it was found that the diagonal cables played a very effective role in controlling the change of horizontal locations; While the vertical cable bracing is also effective in the horizontal response of the structure. Also, by comparing the natural frequencies of the structure in the presented models, the probability of amplification of models with arched configuration and diagonal cable bracing is much less than other models.