Zwaluwenberg N417 ecoduct

On order of the province of North Holland, an Ecoduct was built over the Utrechtseweg in Hilversum (N417).

Contractor K. Dekker B.V.

Zwaluwenberg N417 ecoduct

The ecoduct is part of the ‘Zwaluwenberg Nature Link’. This consists of three different ecoducts. Rijkswaterstaat and ProRail installed two ecoducts over the A27 and the railway line between Utrecht and Hilversum.

The general contractor K. Dekker, which was responsible for the ecoduct over the Utrechtseweg, asked Spanbeton to help work on the structure. Spanbeton took care of the engineering, production and installation of the beams. In March 2014, Spanbeton supplied 30 prestressed SKK box girders with a length of 25 metres.

Structural modification
The requested solution involved a technical risk that was related to the requested crossing angle of about 50 degrees. For this reason, Spanbeton presented a modified solution to the Province to be able to manage that risk. Where an SKK beam deck is normally prestressed transversely, in this case Spanbeton changed this to a deck with a cast-in-place compression layer. This raised the construction height from 1300 to 1420 mm. This resolved the technical risk.