The Extensive Cladding of Drammen Bridge, Norway

Drammen Bridge is an example of how modern needs in the society has affected the design of a large infrastructure project, and increased its environmental quality, sustainabililty and operation by introducing a special tailored bridge enclosure system covering a large part of the whole bridge structure. With a total area of approximately 50.000m², it is belived to be one of the largest of its kind in the world.

The Drammen Bridge is the longest bridge viaduct in Norway. The concrete bridge from the seventies was expanded from two lanes to four by constructing a parallel bridge upstream. In order to make the two separate structures look like one, a steel / aluminum cladding was introduced. This paper describes the background, design, construction and experiences of this environmental effort. The project was finished and opened in 2007.

The cladding serves the following purposes:

• Make the superstructure look like one bridge

• Introduction of an asymmetric geometry of the bridge underneath

• Reduce wind drag

• Keep the bridges free from pigeons

• Better the bridge climate and thereby extend lifetime.

  The cladding consists of a steel frame support system attached to the bridge and cover plates of aluminium sandwich type. One major challenge in the design was that the bridges move differently in longitudinal direction due to a diversing number of expansion joints in the bridge superstructures. Therefore, the cladding has a longitudinal joint in between the two bridges allowing for relative movement. The steel frame support system is attached to the superstructure through steel bars with adjustable length. In this way each panel can be adjusted to perfect alignment. This also makes it possible to change panels later.

  The cladding has a cost of approximate NOK 100 mill, i.e. approximate USD 20 mill. The project is a great success, and has proved that it is worth while to invest in esthetics.