Global response of submerged floating tunnel against underwater explosion

Submerged Floating Tunnels (SFT) for transportation must be designed to secure passengers' safety in case of accidental events. Underwater explosion is the most critical event to long submerged structures. In this paper, first, shock waves and impulse pressures generated by an explosive away from the SFT are expressed by the formulas coming from the experimental results. Second, the SFT tethered by mooring lines and anchors is modeled as a simply supported uniform beam with continuous elastic springs. Finite element analysis for the beam model subjected to the impulse loading from the experimental formulas is conducted by using a commercial code so that the response of the SFT can be investigated. For design purpose, theoretical analysis is also conducted for the same model. Simple equations to show the response of the SFT due to underwater explosion attack were deduced. Time dependent displacements were calculated by these equations. The calculated results were compared with the previous numerical results and proved to give good agreement with them. Theoretical analysis using the simple equations yields solutions so