Stuttgart, S21 underground railway station

DB Projekt Stuttgart–Ulm GmbH has achieved another milestone in the realisation of the Stuttgart 21 project: the last of the approximately 2,000 rammed piles was driven in on 8/8/2019. After an official press conference given by the client, the Team and other project participants celebrated the final ram stroke.

Heavily concentrated load

The foundations of the station building are defined by heavily burdened chalice supports and construction elements stretching right across the exterior walls and the railway station building. The greater part of the entire future railway station and its 28 chalice supports rests on around 2,000 rammed piles installed by PORR.
When in use, the concentrated stresses on the trough walls and chalice supports are directly transferred via the in-situ concrete rammed pile groups below into the subsoil. During pile test loading procedures, piles in a trial field were subjected to pressures of up to 8,000kN (800t). Depending on the individual requirements, construction piles were manufactured to bear loads of up to 4,900kN (490t) each. Where particularly heavy stresses will apply, pile groups of either 24 or 37 rammed piles were configured. The high loads have to be transferred into very heterogenous subsoil. The pile length limitations imposed by water legislation requirements also complicated the process.