Widening and Deepening of A9 Badhoevedorp.

Construction Alliance

On Tuesday, June 9th, the Directorate-General for Public Works and Water Management (Rijkswaterstaat, RWS) issued the so-called ‘Commencement Certificate’ to the construction consortium VeenIX. This means that outdoor work can commence on the project. With a price tag of over €700 million, the expansion of the A9 motorway is one of the largest infrastructure projects in the Netherlands for the coming years.

As part of the Schiphol-Amsterdam-Almere (SAA) route, Rijkswaterstaat is widening the A9 between the Badhoevedorp and Holendrecht junctions and constructing a reversible lane.

The route between Schiphol-Amsterdam-Almere is considered by RWS to be one of the busiest connections in the Netherlands, and in recent years, traffic congestion has increased. This led the government to decide on a large-scale road expansion, consisting of five phases. After previously widening the section between Diemen and Almere (A1) and the A6 to/from Almere, it was now the turn of the fifth and final phase: the A9 between the Badhoevedorp and Holendrecht junctions.

A component of this project is the construction of the ‘Tree Bridge’ near Amstelveen Stadshart. This bicycle and pedestrian bridge, designed by CI-engineers, is characterized by its challenging shapes and harmonious integration with the environment, including rich vegetation and trees.

Some of the existing structures will be renovated, others replaced. Additionally, 14 kilometers of noise barriers will be installed. Included is the 14 years of maintenance after the project’s completion. Near Amstelveen, the A9 will be constructed 1.6 kilometers underground, with three coverings with greenery, allowing the residents of Amstelveen to enjoy a park instead of a highway. The underground sections are located at:

  • Oude Dorp (Amsterdamseweg)
  • Stadshart (Keizer Karelweg)
  • Meander (Bovenlandpad)

Notable elements on the route include the Schiphol Bridge – a double bascule bridge – which needs to be widened. Then there’s the underground section in Amstelveen; a more than one and a half kilometer long waterproof box construction with three coverings: two of 250 meters and one of 85 meters. In addition, there are eleven viaducts that need to be replaced or widened. There’s also an underground section at Holendrecht, a more than 400 meter long underground section with about 100 meters of covering, noise barriers, culverts, bridges for slow traffic, etc.

The project is being executed in five phases. There is a lot of underlying road network, waterways, and the like. These need to be adapted. A complicating factor is the poor soil condition. Settlements of up to about 3 meters and long consolidation times pose additional challenges. During the tender, value was placed on a solution that is as free from hindrance as possible, with ample reuse and minimal material use, uninterrupted traffic flow, and robust solutions.

Project office VeenIX is responsible for the design and realization. CI-engineers, in close cooperation with VeenIX, has taken responsibility for the design of sections of the canopies, underground parts, noise barriers, and existing structures.