LFCS (Design and Verification of Large Floating Coastal Structures) is a research project, funded by the Research Council of Norway, focused on producing recommendations for design of large coastal structures and developing methods and tools for hydroelastic analysis of coastal structures in spatially inhomogeneous environmental conditions and bathymetry.
This paper provides a presentation of the project, and a summary of the related review work on environmental, loads, structural, mooring and physical scaled model tests. Focus is set on floating bridges for fjord crossings. Scaled physical model tests for a floating bridge at SINTEF Ocean's ocean basin (80m × 50m) for March 2020 are in preparation and it is expected that highlights of this activity can also be presented during the presentation at the conference.
Established design and analysis methods for floating structures are based on wave field models that are uniform over the structure. In current design of offshore structures these methods are applied to large rigid bodies as well as systems of interconnected bodies. Considering large floating coastal structures for fjord crossings and near-shore development, every component of environmental loading can vary over the structure; waves can be very different at the two sides of a fjord, wind will be influenced by local topography and current will vary with local bathymetry. The simplest way of dealing with this inhomogeneity is to apply the worst environmental condition to the whole structure. Instinctively this may be taken as conservative. However, in some cases, the uniform load assumption may not be conservative, e.g. in the case of horizontal forces towards the convex side of a curved bridge. The large dimensions (typically 2-4 km for fjord crossing floating bridges) will cause the structure to be quite flexible, and the coupling between the structural deflection and water movement due to waves and current (hydroelasticity) will not be negligible as in the case of traditional rigid bodies, and this interaction may become crucial.