Hydrodynamic Loads on a Submerged Floating Tube Bridge Induced by a Passing Ship or Two Ships in Maneuver in Calm Water

The European highway E39 ferry-free Project led by the Norwegian Public Roads Administration (Statens vegvesen, NPRA) is in its full momentum on solving the technological challenges to cross the deep (up to 1350 m) and wide (up to around 6 km) Norwegian fjords. Different types of crossing solutions have been explored up to now. The current paper is related to the submerged floating tube bridge (SFTB) solution. But the model itself can be applied to any other structure that may experience loads induced by a passing vessel. The method of Xiang and Faltinsen (2010) for evaluating the calm water interacting loads between two vessels up to the point of collision has been extended to include an SFTB. Equations of loads are extended to include also the vertical load and pitch moment on the body in question. The vertical load induced on the SFTB is investigated for the purpose of identifying the significance of this effect on the design. The investigation includes this effect under different maneuver scenarios of the passing vessels: a single ship passing, two ships advancing in side-by-side positions, encountering or overtaking maneuvers. In addition, parametric studies on the submergence of floating tube bridge, and vessel speeds are studied to get more understanding of this effect. A simple exercise shows that it is worth of further investigation on ship-induced surface waves effects on the structures in vicinity of the ship path. Finally, the evaluated loads are compared with other types of loads from the analysis results of the on-going NPRA SFTB design.