Concept overview of a multi-span suspension bridge on floating foundations

A ground-breaking solution is envisaged for the crossing of Bjørnafjorden on the West coast of Norway. The proposed solution consists of a three span suspension bridge whose two central pylons rest on floaters. The floaters are inspired by the Tension-leg platform technology commonly used in the offshore industry in areas of extreme depths. Similarly to Tension-leg platforms, the floaters are anchored to the seabed by means of vertical tethers. Different floater geometries, both in concrete and steel, have been considered. A top cable has been introduced between the top pylons in order to provide the system with sufficient longitudinal stiffness to accommodate the asymmetric traffic load situations that would, otherwise, lead to large deflections in the loaded spans. The rest of the superstructure consists of the main suspension cables, pylons, hangers and an aero-dynamical bridge girder. Multi-span suspension bridges, tension-leg platforms and top cables are known and proven technologies however they are brought to an unprecedented scale and combined into a construction that could become one of the world’s most innovative bridges.