The Circle Bridge, Denmark

The Circle Bridge (Cirkelbroen) is a 35m long bridge that spans Copenhagen's Christianshavns Canal, designed by the Danish-Icelandic artist Olafur Eliasson. The bridge is part of the pedestrian and cycle route along the quays of Copenhagen, a route that is used by thousands of people in Copenhagen every day. The bridge consists of five steel platforms that vary in diameter from 10 to 14m and are arranged to create a staggered, zigzag path across the water. The platforms are topped by tall masts from which thin steel cables extend to the platform’s circular railings, outlining barely perceptible conical screens around the masts – the highest of which rises 25m above the bridge. The indirect route that the layout forces people to take inspires reflection and pause. Cirkelbroen, which translates to ‘circle bridge’, is lit at night. One section of the bridge functions like a swing bridge, rotating on submerged pontoons to allow large boats to pass into and out of the canal. Cirkelbroen has been selected as the official Danish logo of the UEFA soccer championship in 2020 hosted by 13 European cities to celebrate the 60 years anniversary of UEFA.

Of the many unique design features of the bridge the fact that it floats when it opens is one of the more noteworthy. The bridge consists of five platforms which are connected to each other as shown on the photos. Two of them are fixed to the foundations whereas the remaining three are the moveable part of the bridge. These three platforms are supported by one column in the centre of the largest platform. From there the bridge is cantilevered with no support under the other two platforms except for a 110m³ buoyancy tank under the water that carries most of the self-weight of the moveable platform. When the bridge is in it closed position it is supported at the ramps on the north side, but when it is to open this support is removed and the bridge floats allowing it to move as a ship in the water. By having the buoyancy tank the structural members in the bridge could be reduced significantly maintaining the slender design envisaged by the artist. The bridge is opened by the use of three hydraulic pistons that turns the bridge around the centre support column. A spherical bearing is placed at the top of the column to support the moveable part and below water there is a sliding bearing between the inner (fixed) and outer (moveable) column.

Owner: Municipality of Copenhagen
Structural Design: Ramboll Denmark
Contractor: Pihl, KSM, C. G. Jensen
Artist: Studio Olafur Eliasson
Service Date: 22 August 2015
Steel: 185tonnes
Cost: €10m