Design Scheme and Structure Analysis of Dongwuyang Submerged Floating Tunnel

The construction of sea-crossing channels has become an important part of the transportation infrastructure construction, and is developing in the direction of a larger span, deeper foundation and more complex system. Compared with traditional bridges, the sea-crossing bridges are facing the challenges of structural durability, wind resistance, complex environment and construction difficulties. In order to deal with the various challenges encountered in the design, construction and operation of the sea crossing channels, this paper puts forward the scheme combining immersed tunnel with submerged floating tunnel for crossing the Dongwuyang water area in Fujian Province, China after considering the topographic, geological and hydrological conditions. The cross section of SFT tube, arrangement of cables and the type of foundation were preliminary designed. The tube deformation, stress and cable force of the submerged floating tunnel under different load combinations were also analyzed by Midas/Civil. The global dynamic response analysis of the SFT structure under the wave and current load was carried out by ABAQUS. The static stress distribution of the SFT concrete tube was analyzed by the 3D finite element model. The results show that under the action of environment and service loads, the design indexes such as internal force, deformation and acceleration of the SFT tube meet the requirements of the design code, which indicates the SFT scheme is feasible, and it has good advantage for the deep-water construction environment.