Seismic analysis of a SFT solution for the Messina Strait crossing

Martire G., Faggiano B., Mazzolani F. M., Zollo A., Stabile T. A.

Procedia Engineering, 4 pp. 303–310, 2010 | doi: 10.1016/j.proeng.2010.08.034

ABSTRACT:

In this paper the seismic behaviour of a Submerged Floating Tunnel (SFT) solution for the Messina Strait Crossing is investigated. The Submerged Floating Tunnel (SFT) is an innovative structural solution for the realization of waterway crossings, which features several advantages from the structural, economic and environmental impact points of view. In particular, it seems to be a suitable system for waterway crossings in high seismicity zones, thanks to the deformability of the overall structure. Moreover the interaction with the water provides additional damping and inertia to the structural motion.

In order to evaluate the SFT structural response to seismic events, time domain dynamic analyses are carried out considering a ground multi-support excitation scenario determined through the generation of synthetic accelerograms by simulating the fault breaking mechanism. This is important due to the distance among the tunnel supports, also because it can lead to significant excitation of tunnel vibration modes featuring a negligible participating mass, which would not be excited in case of synchronous ground motion. Moreover the propagation of the vertical ground motion into the water and the fluid-structure interaction are taken into account in the analyses. Different structural solutions are considered, mainly differing for the cable system configuration. The dynamic properties of the considered solutions and the main aspects of their structural response are illustrated. The obtained results, although they cannot lead to definitive conclusions, give useful indications about the seismic response of Submerged Floating Tunnels and confirm that such an innovative structural solution for waterway crossings feature great potentialities, in particular when large spans have to be surpassed, such as in the Messina Strait crossing.