Three of the seven gigantic roof sections for the additional passenger tunnel at Amsterdam Zuid station, the Brittenpassage, are already in position. During the eight-day closure of the A10 Zuid in August, we will also be putting the fourth and fifth roof sections into their final positions. They are already sitting waiting on the work site in Arnold Schönberglaan, just south of the A10. The two concrete giants are waiting to be moved slightly to the north. But lots more needs to happen before this process can start. ‘The shifting process may look extraordinary, but it’s actually a moment of rest for us’, laughs Geo van Tintelen, project lead Nieuw-Zuid construction consortium. ‘Preparing for it really is precision work: it’s all a matter of millimetres.’
Excavation work, facing walls and tunnel demolition
At 22.00 on 5 August, we will close the A10 Zuid, and dig up around a length of around 100 m. We will also remove two railway tracks and the temporary platform. We will then demolish part of the old Amstelveen bend (Amstelveenboog), the tunnel through which the metro and tram line 51 ran until early 2019. At the same time, we will start to put in place the facing walls for the abutments that we built in the summer last year. These abutments serve to support the heavy roof sections on either side and the facing walls separate the structure from the ground behind it. ‘But you can’t just support the roof section on an abutment like that’, explains Van Tintelen. ‘You need what are known as bearings between the abutment and the roof section. That will be quite a challenge.’
Positioning heavy bearings
The bearings literally provide freedom of movement for the roof section. Van Tintelen: ‘As you can imagine, the concrete roof section can expand and contract as a result of the weather. It will also have to support a gigantic traffic load: so it needs to be able to move a little. The bearings help spread the load.’ Positioning the bearings for the fifth and most southerly roof section, the largest so far, will require a high level of precision. ‘For smaller roof sections, you can use steel-reinforced elastomeric bearing pads, made from rubber and steel. For this larger roof section, that’s not sufficient and spherical bearings are required. Each one of these steel components weighs 3.5 tonnes and must be positioned with millimetre precision.’
Just push it
At the same time as fitting the bearings, we will also be putting the runners in place across which we will be pushing the roof sections into position. We expect to start that process on 9 August. We will be moving the roof sections separately, because they are too heavy to shift simultaneously. Each roof section will take around four hours. Once the roof sections are in their position, we can remove the runners and put the bearings in place with concrete. We are using a special concrete-pouring method that hardens within eight hours. We will then be able to replace the A10, the track and platform. We are rebuilding the A10 with a bend in it, to make it possible to widen the temporary railway platform. By the morning rush-hour on Monday 14 August, drivers will be travelling on a fresh layer of asphalt.
Five of the seven roof sections soon in position
We built the first roof section for the Brittenpassage in 2019. In November 2019, we put this roof section into position underneath railway tracks 2 and 3. In August 2021, they were followed by the roof sections underneath railway track 4 and a metro track. In August 2023, we will position the fourth and fifth roof sections underneath railway platform 1 and future platforms 5 and 6.
Ask your question
During the eight-day closure of the A10, drivers can make use of the Zuidasdok Ask&Go service and ask questions about driving and travelling during the works via WhatsApp. There are two ways of doing this:
- Scan the QR code
- Start a Whatsapp chat with Ask&Go Zuidasdok (085-0659091)
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