The 1,842m-long, four-lane bridge on the E-18 highway, Norway, is the fourth bridge across the Drammen River. The new hollow-box girder bridge, as part of the extensive road-widening programme in and around Drammen, was built next to the existing Drammen Bridge and was open to the public by December 2006.
The total value of the project is estimated at NOK874m ($78,676,905) and the construction works for the new bridge began in December 2004.
The main objective of the new bridge project was to ease the traffic congestion on the existing two-lane bridge connecting Oslo and the surrounding areas along the coast. The State Public Road Administration has also expanded the E-18 motorway bridge from two lanes to four lanes. Around 22,000 vehicles use the bridge every day and this is the only way to connect Oslo with surrounding areas.
The project was divided into two phases; the first phase was the construction of the new bridge alongside the existing bridge, the second has focused on upgrading the existing bridge. The ongoing construction of the new bridge did not disrupt the E-18 traffic during the project.
The new bridge was open to traffic in December 2006; upgrade works on the existing bridge then got underway.
As part of the upgrade plan of the existing bridge, circular columns replaced the original rectangular columns and an aluminium bridge façade enclosure consisting of aluminium sandwich plates in a steel grid supplied by Alcubond was fitted to the underside of both bridge super structures. This was done to match the design of the new bridge with the old and make them appear as a single structure.
The underside also had a lighting system fitted so that the bridge could be seen from the river. The new panelling covers the whole width of both bridges, the gap in between and a total length of more than 1,700m (42,000m²).
The parks, footpaths and surrounding infrastructure were refurbished in the final stages of the project and this was completed in September 2007.
The Norwegian government financed the project and awarded the foundation contract to NCC and construction contact to Skanska. Arkitektskap AS was responsible for the architectural design and Aas-Jakobsen for the structural design for the bridge.
The estimated investments on the foundation work and the construction work were NOK108.2m and NOK435.6m respectively. About NOK60m was spent on upgrade of the approach roads and NOK30m for miscellaneous works. Another NOK150m was spent on the aluminium sheet encasing and new pier columns on the old bridge.
ARCHITECTURE AND DESIGN
The new bridge has 42 spans of 20m to 60m. The pier columns were built in a circular cross-section of Ø2m. The variations in span lengths were planned to accommodate the bridge to the existing infrastructure. Of the total spans, the major 36 spans have single, circular columns. The maximum clearance to the water is 11m.
The new and existing bridges now appear as a single structure. The deck structures of the new and old bridges are equal in design except for a small variation in the lower inside of the box girder of the new bridge.
Standing 0.6m apart, the two bridges have similar concrete side beams, railings, noise shielding and aluminium sheet covering encasing the underside.
During the construction, a Movable Shuttering System (MSS) was used to carry the separate spans. A movable steel box-girder was positioned above the bridge deck-span and formwork was suspended from the steel girders by threaded steel rods to avoid unwanted deflections.
NCC carried out the foundation, engineering and concrete contract. The concrete structures were made up of cast-in-ground steel pillars. NCC also built all the necessary overtaking ramps. A total of 41 foundations were planned, of which 11 were underwater and 30 on land.
Five different types of piles will support the bridge and each type of pile is placed in a group designed to take the actual load on each pier foundation. Every pile group was capped by a concrete foundation at ground level and in the river. The pile caps are underwater with a plinth rising to the surface.