The Dynamic Behavior Of Submerged Floating Tunnel Under Consideration Of Theaction Of Pipe Connection

Submerged floating tunnel (SFT), also as known as the Archimedes Bridge, isa new type of transportation across the waters. It is fixed in water by the jointaction of its own weight, buoyancy and anchoring system. It is located at adistance of20m below the water surface in order to make the large-tonnageships pass through. Submerged floating tunnel consists of the tubular structurein water, archoring system in foundation or water pontoon device, and theconnection structure in both sides. It is a creative transportation structurecrossing channel, river, lake, etc.In past few years, numbers of scholars have studied the dynamic response ofSFT’s tube, archoring system and couple-mode of tube and archoring syetem.Few researchers simplified SFT as an elastically supported beam with springsand damping on each end. In this paper, the research work will be conductedon the dynamic response of elastically supported SFT under vortex-inducedvibration and moving loads in uniform flows, where the SFT will beapproximated as the superposition of the shape of the flexible deflection of thebeam with simple supports and the shape of a rigid beam supported by theelastic springs and damping.The main reseaech contents are as follows:(1)Considering, the SFT is simplified as an elastically supported beam withsprings and damping on each end, and its structural dynamics equation underearthquake vortex-induced vibration in uniform flow is established. Theequation is sovled by using the Galerkin method and the modal superpositionmethod. The time-displacement diagrams are gained by applying Matlab. Byanalyzing the time-displacement diagrams, it can be concluded the dynamicresponse of the SFT, and the influence of damping and spring of the elasticbearings upon the SFT.(2)Regarding the tube of SFT as research object, the SFT model undermoving loads is established. By the use of the Galerkin method and the modalsuperposition method for the vibration differential equation, the displacement oftube under the moving loads is simulated by Matlab. By analyzing thesimulation results, it can be known the influence of the loads of different size and velocity, elastically support of differnet damping and rigidity upon theSFT’s displacement.