Photo: Hålogalandsbrua as

COWI to design Norway's longest suspension bridge 

Rombak fjord near Narvik in north Norway is to be spanned by the world's seventh longest suspension bridge with a main span of 1,345 metres. COWI is currently working on the scheme design.

"A slender bridge" - this is how project manager Lars Jensen of COWI describes the suspension bridge which is to cross Rombak fjord to the Øyfjord peninsula in north Norway. Not only is the bridge one of the ten longest suspension bridges in the world, with its 1,345-metre main span: it is also unusually narrow.

With a mere 15 metres between the main cables, the team responsible for the bridge is facing an exceptional challenge.

"The extremely slender design gives the bridge a very low critical wind velocity, i.e. the maximum wind speed at which the bridge remains stable. So our challenge is to design the bridge such that it is stable under the wind conditions in that location," explains Lars Jensen.

Photo: Hålogalandsbrua as
Visualisation of the finished bridge.


Seventh longest suspension bridge

To be known as Hålogalandsbrua, the bridge will be the seventh longest suspension bridge after, amongst others, the Great Belt Bridge, which was also designed by COWI.

The bridge has been commissioned by the Norwegian Highways Authority. The companies appointed for the scheme design and detailed design are COWI in Norway and Denmark, Johs. Holt of Norway and Dissing+Weitling of Denmark. COWI also has responsibility for follow-up during the construction phase. The cost of the bridge is expected to be in the region of NOK 1.5 billion, with COWI's contract amounting to DKK 10-12 million.

Relatively light traffic

The narrowness of the bridge is due in part to the relatively light flow of traffic on this stretch, which therefore needs no more than two lanes for road traffic. An additional lane for pedestrians or cyclists is also planned.

"A suspension bridge is the appropriate solution as the stretch to be spanned is some 1,300 metres of water and the fjord is really deep. It would be impossible to place the foundations for, say, a cable-stayed bridge," says Lars Jensen.

The scheme design is to be ready in November after which it is to be submitted for final consideration by the Norwegian Parliament. Final adoption is expected in the autumn of 2008.

By Janne Toft Jensen, jaje@cowi.dk
Published: 10.08.2007