Launching rail decks in Brussels

This project involved sliding into place and lowering 38 rail decks, using launching technology, over a curved section of twice 420 metres.

Client:
TUC Rail
Location:
Brussel
Lanceren
Lanceren 2
Lanceren 3

Project

Positioning decks

The decks were delivered on low-bed trailers at the start location, where screw-jacks were mounted at the head of the decks. At the front of the deck, a screw-jack with one screw was positioned. At the back, a trestle with two screw-jack points was positioned. The deck was screw-jacked at the back with screw-jacks mounted on rail beds.
 
The run-up track was positioned at the definitive location of the deck. The deck was slid to above the run-up track. In this way, the screw-jacks were attached to the rail beds by means of grippers on those rail beds. 

Relocating and rotating the run-up track

When the deck was located above its definitive position, the run-up track could be moved to the position of the next deck to be slotted in. Here, the run-up track was (vertically) guided by a run-up track bracket above the deck and a roller guide under the deck.
 
The nose of the run-up track was shifted to above the next pier. When the nose was above the pier, the run-up track was mounted on it using a screw-jack attached to the nose of the run-up track. After the run-up track was mounted, it was rotated to the correct horizontal orientation. The run-up track could now be slid through completely. Here, the hindmost point of the run-up track was levelled with the axis of the pier. 

Lowering decks

While sliding the run-up track, the deck at the back was mounted on the deck that was just positioned and, at the front, the screw-jack was resting on the pier. Given that the screw-jack point was situated directly above the pre-stressed head of the pier head, an adjusted point of support was used.

After shifting the run-up track, the deck could be lowered to around 1.7 metres. That made it possible to install successive decks using the same routine.