Freyssinet has developed three different technologies for sliding complete structures from their fabrication area to their installation site. They consist of prefabricating a structure next to the railway track or the road and quickly transferring it to its final position during a brief period of track closure (approx. two days) in order to minimise traffic disruption.
This technique consists of completely clearing the ground and sliding the structure on bentonite grout using Hebetec 1,000-tonne jacks. Once the sliding is complete, backfilling takes place in order to re-open the route to traffic.
This technique consists of partly clearing the ground and then sliding and driving the structure forwards into the infill as the excavation work progresses, using the same equipment as for the Autoripage® technique. No backfilling is required as the volume of earth excavated is identical to the volume of the structure.
Air Pad Sliding
This technique is identical to the Autoripage® technique, with air pad sliding bearings (APS modules) in lieu of bentonite. It consists of completely clearing the ground, installing skidways, then moving the structure on APS modules, which have a friction coefficient of less than 1%. Once the sliding is complete, backfilling takes place in order to re-open the route to traffic.