Bridge, Katwijk

Bridge, Amsterdam NL, Project Team: René van Zuuk, Client: Municipality of Amsterdam, Start of design: 2004, Completion: 2010, Floor area: 940 m², Cost: €1.974.000

The municipalities of Katwijk and Oegstgeest wished to construct a mild-traffic bridge over the Oude Rijn canal, between 't Duyfrak (Katwijk) and Nieuw-Rijngeest (Oestgeest). The project is intended for use by pedestrians and cyclists. The bridge not only connects the adjacent neighborhoods, but also becomes a landmark in the recreational cycling network between the lakes and coastal dunes of the area, providing a connecting link in the cycling route from Katwijk to Leiden. Since most bridge designs are static, it is always special for an architect to create a dynamic object. Due to its movement, the impression of the bridge changes, creating sufficient visual stimulation. Additionally, a location on the water is always special, as it makes the project stand out. The chosen location is even more important, since the bridge serves as a gate between the two aforementioned areas.

As regards the design process, the design of the bridge was finalized through an integral procedure. From the beginning, the members of the team worked closely together to conclude to the final form, while at the same contributing their individual input.

In the beginning, the urban scheme of the area was analyzed. The urban tissue of Nieuw-Rhijngeest in Oegst-Geest and 't Druyfrak in Katwijk, will soon become a homogenous part of the city, intersected by the Oude Rijn canal. It is striking that the building volumes in Oegstgeest are a little more frivolous than the ones in Katwijk. The architecture of the boroughs appears to be heavy, classical, deriving its style from the 1930's, characterized by many red and yellow brick facades, combined with pronounced white, window frames. The area unfolds through a network of ditches and canals, which, combined with the plentiful green space, give it the appearance of a dutch fishing village. The road pattern runs parallel to the water, with many small bridges interconnecting the streets. The existing bridges have a classic shape. They all have one feature in common and that is their steel, anthracite-colored u-shaped beam. The beams give the bridges an industrial appearance.

As regards the type of the bridge, two options were established. The first was to create a dynamic bascule bridge, and the second, to design an asymmetrical swing bridge. Both types have their own advantages and disadvantages. An asymmetrical swing bridge boasts a simple swing mechanism and easy accessibility from land. The bridge fender in this design would also be cheaper. However, the disadvantage is that the span is larger and the bridge must be separately balanced. The bigger gap would now have to be connected with a cable supported bridge, but that posed many structural problems. Moreover, a swing bridge may be rare in the dutch landscape, but it is not unique. That is why we adopted the solution of a dynamic bascule bridge, a very obvious solution but seldomly applied. This solution provides a powerful image that blends well with the surrounding landscape. In addition, the bridge has a shorter clearance time.

Finally, as regards the architecture and function, the bridge is viewed as both a technical and architectural object, combining functionality and form. The bridge has of course two positions, an open and a closed one, both of which are architecturally designed. In the open position, the ballast arch forms a gate symbolizing the transition from Katwijk to Oegstgeest. A dynamic image is created by stretching the pylons backwards, compensated by the counter-movement of the ballast arch. The asymmetric design provides the passer-by with different views from different angles. The shape is robust and the arch creates a distinctive silhouette.