Stuttgart 21, Germany – Implenia

Stuttgart 21 is one of the largest construction projects in Europe. The railway line, which connects Ulm with Stuttgart, includes an underground station and a train tunnel. Simply Precast Accessories supplied the bespoke concrete spacers with PP fibre from Molenaar for this project.

Our Customer Implenia Switzerland’s largest construction company built the Stuttgart 21 using a Tunnel Boring Machine and we were commissioned to source the concrete spacers with plastic clip for the project. With our partner Molenaar we devised a special spacer.

Fire safety, a major challenge

The tunnel was built using round tunnel elements our 3 point concrete spacers are ideally suited for this type of structure. However, there was another big challenge: fire safety. Stuttgart 21 had to meet special requirements. If a fire broke out, the moisture would expand and everything would burst apart. That’s why we equipped the spacers with a special PP fibre. When heated, the fibre melts and the moisture finds its way out preventing extreme concrete explosions. In this way, we were able to meet the quality requirements and win the contract.

The project in Stuttgart was built on site. A temporary field factory was set up next to the construction site, where the precast concrete elements were made directly, at the start of the tunnel. For us, Stuttgart 21 was completed in 2019. But according to the planning, trains will not be running on this track before 2025

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