Ingenieursbureau Boorsma b.v.
Zoetermeer, the Netherlands
The Jan Waaijerbridge (projectname: Hobbema 2.0) is a new connection for cyclists and pedestrians between Westerpark and New Driemanspolder in Zoetermeer, the Netherlands. With a total length of 220 m, the weight of the new bridge approximates 375 tons of steel. Weathertight steel (Cortensteel) is used for the main structure of the bridge, and the railings are made of stainless steel. During the project the bridge was renamed as a tribute to Jan Waaijer, the former mayor of the municipality of Zoetermeer. Light fixtures, with a diameter of 3 m, are supported by the slender and tapered columns.
A painting from the 17th century, “The Lane of Middelharnis” made by Hobbema, inspired Syb van Breda & Co for the design of the bridge. In the painting, very slender trees are reflected by the columns on both sides of the bridge.
The double curved alignment with continuous changing cross-section was the main challenge of the project. As a result of this complex design almost every component of the bridge has unique geometry.
New structural details were developed because structural feasibility was not considered well enough in the main design phase. This caused delay in planning, which was solved by changing the order of the construction process. Because of the time aspect it was not possible to complete the final 3D model of the bridge before generation of the construction drawings and cutter-files. Therefore a quick modeling process was developed. The bridge was divided in a sequence of components which were calculated, drawn, and manufactured consecutively. This resulted in a time efficient process with short design and manufacturing periods.
For transportation the bridge was divided in five components, which are mutually dilated. The components were divided in unique elements (6 to 12 parts) which were transported to the construction site. The components were assembled on location by means of welding. For this purpose manholes which enabled welding in the interior of the bridge elements were made in the bridge deck.
Ingenieursbureau Boorsma BV was responsible for the implementation design of this steel bridge. All construction drawings and cutter files were generated with Tekla Structures. Almost every single steel plate is unique and has been generated from the 3D Tekla model. A successful project was realized, even though the design of the bridge was complex and the time allowed very short.