Improving infrastructure while reinforcing ecological values

Road expansion A1/A6 Diemen – Almere Havendreef

ZJA was involved as an architect in one of the largest infrastructure projects in the Netherlands, known as the SAA project (Schiphol-Amsterdam- Almere). It was concerned with the eastern part of the project, expanding and improving the link between Amsterdam (A1) and Almere (A6). This involved the rerouting of the A1, a bridge over the Amsterdam-Rhine Canal, an aqueduct for the River Vecht, a railway bridge over the A1, a second Holland Bridge to Almere, and a large number of new viaducts, underpasses and noise barriers. Read more about this project

The motorist driving in this area is confronted with an excess of exits and merging lanes, junctions, bridges and underpasses. In combination with the many lanes and the intensity of the traffic this is quite an assault on the senses. The most important design decision is therefore to choose for modest and uniform shapes, with simple and recurring elements. The more chance one’s eyes get to wander into the distance and experience the alternating landscape, the better.

– Reinald Top, architect-partner at ZJA

Major work

The results exemplify the central principle of ZJA’s design philosophy, its determination to optimize the utility value, experiential value and future value of precious space. The starting point was a basic concept that distinguishes between three landscapes: new land, old land, and the peatland area around the Vecht that lies in between. The guiding purpose was to optimize the experience of the landscape from the motorway. The architecture of the road and its intersections is therefore restrained, and where possible it fits into the landscape. Here and there an eye-catcher draws the attention, as a visual attraction and orientation point. Primacy is given to the creation of calmness and clarity, visibility and safety.

Embedding of concrete and steel colossi

The project includes structures of exceptional dimensions, among them the broadest aqueduct in Europe and a railway bridge with the longest span in the Netherlands. The demolition and rerouting of one of the widest motorways in the country was unique too. What design logic do you apply to such vast interventions and additions in the landscape?

One striking example can be seen in the aqueduct carrying the River Vecht at Muiden. The design is based on the idea that the river, with its dikes, banks and local roads, needs to be treated as a whole, and that the A1 must leave the landscape intact as it crosses under the river.

This explains the huge width of the aqueduct (65 metres) and the very gradual incorporation of the motorway beneath it, over a length of 620 metres. The low noise barriers on both sides are angled backwards, so that the landscape remains visible from the A1.

Anything that could disturb that view has been concealed and integrated, including cable ducts, matrix displays and camera systems. You can see sailing ships passing through the green fields.

In the new bridge over the Amsterdam-Rhine Canal and the second Holland Bridge, technical innovations and astute design choices once again combine to make these major works as slim as possible and a natural part of the landscape. Multiple thinner, lower bridge decks allow a view of the water. Vertical bars in the balustrades placed at the correct distance apart disappear when passed at 100 kilometres an hour, because of the stroboscopic effect. Colours, plentiful daylight and lighting installed as accentuation ensure that the experience of the road user at tunnels and bridges connects as comfortably as possible with the surrounding landscape. All the viaducts are recognizable as members of the same family of designs.

The big steel railway bridge

Designing the railway bridge at Muiderberg (the Zandhazen Bridge), which crosses the A1 diagonally, was all about making the experience of the motorist as reassuring as possible. The use of high-quality steel enabled the tied-arch bridge with its enormous span to be fairly slim. The sides of the twin arches are inclined inwards, so that they almost touch, giving free play to the light. Together with the chosen colour, which matches the usually light-grey sky of the Netherlands, this softens the impression made on anyone approaching the vast structure at high speed. Against the background of trees, the dark bridge deck over which trains travel almost vanishes. What is left is a moment of visual astonishment as you drive underneath, without any sense of being unsafe. A further contribution is made by the meticulous harmonization of the distance between railway portals and the distance between the diagonals in the bridge.

The colour of the arches matches the often light-grey sky of the Netherlands. Against the background of trees, the dark bridge deck seems to vanish.

Read more about the project


Awards: De Zandhazenbrug, spoorbrug, Muiderberg Nationale Staalprijs 2018.

Architect: ZJA
Klant: Rijkswaterstaat

Opdrachtgever: SAAone (VolkerWessels, Boskalis, HOCHTIEF, DIF)
Landscape architect: OKRA Landschapsarchitecten
Jaar: 2017

Project: #686

Foto's: Rijkswaterstaat, Dutch Road Movies, ZJA



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