The structural response of submerged floating tunnel to multi-support seismic excitations

In this paper the structural response of Submerged Floating Tunnels (SFTs) to seismic events is SFT is an innovative structural typology for waterway crossings, which consists of a tunnel placed underwater at a certain depth below the free surface and fixed in position by means of anchorage cables. Thanks to the deformability provided by the cables restrain condition, SFTs should represent a reliable solution for strait crossings even in high seismicity zones. Time domain dynamic analysis are carried out on different case studies, considering ground multi-support excitation determined through the generation of synthetic accelerograms by simulating the fault breaking mechanism. The main aspects of the structural behaviour are illustrated; results show the complexity of the seismic response of SFTs and, at the same time, give useful indications about critical aspects of the design.