After almost a year of preparation, it’s actually happening: two sections of the roof for the additional underpass at Amsterdam Zuid station will be moved into position on the morning of Saturday, 21 August. This means that, starting at 20:00 on the evening of Thursday, 19 August, there will be a reduced train and metro service. Over a week ago, we already removed sections of the emergency platform that is located between tracks 3 and 4. Starting on Friday, 20 August, we will be digging out the soil from under this emergency platform. We will also be removing railway track 4 and metro track 1.
When the tracks and platform have been removed, we will be able to put in place the runners that we will use to shift the concrete slabs into position. Sections of the runners are already in place. There will be four: one at each end and two between them. The last two are support structures: the roof sections are 70 m long and 2 m thick and therefore require additional support. These two central runners will be placed on foundation piles inserted previously.
Grippers and jacks
Part of the new platform is also attached to the roof section that will be underneath railway track 4. This will serve as a storage place for materials that we will be using to complete the job this weekend. They include the so-called grippers or jacks that will be used to push the concrete slabs forward. This shifting work will start with mini-grippers that are able to move the two roof sections several decimetres forward in this very limited space. As soon as sufficient room has been created, larger grippers will be used. The grippers will be attached to the runners, to which we will then attach jacks (the tubular units). When the shifting process has reached far enough, we will use another jack behind it to push it further.
The two sections of the roof have already been lifted (or rather pushed) out of their formwork by jacks. They are now resting on the runners that will take them to their final position. The two roof sections have already been moved several centimetres in order to gauge exactly how much pressure will be needed to get everything moving.