Swansea Sail Bridge, UK

Project Description:

The client asked for a bridge to provide an essential crossing for pedestrians and cyclists from Swansea city centre to the new Port Tawe Innovation Village in what used to be the busy docks area of the city. The result is this unique award-winning cable stayed design in which the curved 140m long deck is supported along one edge only by 70mm stay cables and a 50m inclined steel mast.

The deck has a slender steel box girder to provide the torsional stiffness needed because of the eccentric stay cable support, and cantilevered ribs to carry the lightweight aluminium planks forming the footway along the outside of the curve. Tuned mass dampers control the vibration amplitudes from potential dynamic excitation by large crowds, and aerodynamic fairings are included on the upstream side to control wind-induced vibrations.

The design and construction was carried out under extreme time pressures to meet planning constraints, and the bridge was delivered from concept to completion, together with a second crossing downstream, in just 16 months.