Mobility demand in Randstad continues to grow, doing nothing was not an option

Restructuring A9 near Amstelveen in the picture

It is perhaps Rijkswaterstaat's biggest restructuring task at the moment: the widening of the A9 between Badhoevedorp and Holendrecht, near Amstelveen and Ouderkerk aan de Amstel. Optimizing the "Second Ring of Amsterdam" is the latest phase in a series of modifications on the A9 between Amsterdam/Schiphol and Almere. "If we didn't tackle the road network here, the Randstad would grind to a halt," says Lammert Postma, environment manager at Rijkswaterstaat.

A brief summary: the A9 will be widened from 2×3 to 2×4 lanes, three canopies will be built at various locations near Amstelveen, the highway itself will be sunken, all noise barriers will be replaced by new high screens and low-noise asphalt - two-layer ZOAB fine - will be laid. 

"In this part of the Randstad, we are seeing substantial growth in population. Employment is also expected to increase and so you can expect that there will continue to be major mobility issues," says Postma. "So this part of the A9 is an important link. Of course, the livability of Amstelveen will get a big boost. For example, the north-south connection will be improved: the highway will no longer be seen as an annoying obstacle. Noise pollution will be reduced and the Old Village will once again become a cultural hotspot with lots of greenery and restaurants. So it's not only the motorists who win: the residents will also reap the benefits."

Three challenges

According to Postma, there were three major challenges with this restructuring. "First, it is our duty that motorists on the A9 can continue to drive as usual during the reconstruction work. After all, to stand still is to go backwards. In addition, we must keep the inconvenience of the reconstruction for the residents of Amstelveen as acceptable as possible. Preferably: no disruption at all. And, we have to deal with exceptionally poor soil conditions on parts of the route. How are we going to deal with that?"

Postma explains that several purchases had to be made (mainly farms and residential houses) to create space for the widening. "In addition, construction combination VeenIX devised the so-called DDI (Diverging Diamond Interchange) near Amstelveen. At 50% of space we now manage to still handle all traffic flows. She also came up with a good plan for a bypass ('temporary A9') that is now south of the old inner shoulder. As a result, the traffic flow will be guaranteed. It is clear that we did not proceed overnight. The area is home to large organizations and companies, such as the Johan Cruijff ArenA, the AMC and the ZiggoDome, which have an interest in good traffic flow, especially if there are events taking place. Never mind that you don't want a surgeon to be late for his surgery appointment at the AMC. We were at the table with all the stakeholders from day one. You have an incredible number of connections and interests here."

Water Management

How to deal with the poor soil conditions - especially at Ouderkerk aan de Amstel - became a challenge for Madrid-based Spanish company FCC. It is part of the VeenIX construction consortium that won the European tender. "Around the A9 there is a lot of peat soil and there are many different polders whose water management has to be kept in order. After all, during the work you want to prevent the bottom of the ditches - next to the A9 - from getting higher than the surrounding ground level. Around Amstelveen we are dealing with sixteen polders."

Nevertheless, an important change took place during the process. "Where it had first been decided to build a tunnel, this was changed to a sunken location of 1.6 kilometers with three canopies. In order to match the noise levels for the surrounding area with the (fictitious) tunnel situation - 'You will be less bothered by the new A9' - we had to install high noise barriers and the new, quiet, double-layer asphalt type ZOAB fine. In this way we again complied with the Environmental Pollution Act, which regulates the maximum level of noise you can have on your facade."

Sustainability

In today's zeitgeist, you obviously cannot escape sustainability issues. Postma: "Of course we asked ourselves: what do we do with the old concrete of, for example, the A9 viaduct over the Keizer Karelweg? It is your duty - also as Rijkswaterstaat - to think about recycling. Well, we were able to organize the reuse of the concrete bridge girders very well. Those parts have been dismantled and are now going to a viaduct in Limburg, among other places. There they are put on a solid foundation. I think this is a good example of Cradle-to-Cradle and we have thus avoided having to produce new concrete - for those other locations in the Netherlands. So acting sustainably!"

"Furthermore, this part of the A9 will become perhaps one of the most energy-efficient highways in the country," Postma states. "At two locations there will be a field of solar panels: this will provide all the energy for the public lighting, the signaling of the matrix signs as well as getting the Schipholburg moving for shipping."

The miles of sheet piling obviously required a large amount of steel to build a stable container. "All the steel came from Ukraine. That is more difficult now. Everyone knows why. We are now literally looking around the world for more steel. What I am absolutely proud of are the steel falls of the new Schiphol Bridge. These are Rijkswaterstaat's largest movable bridge traps in the Netherlands. But fair's fair: the motorist himself ultimately wants to get from A to B as quickly and safely as possible.

The new A9 near Amstelveen is expected to be completed in 2027.