Brenner Base Tunnel: Intersection Block Successfully Cast

The Brenner Base Tunnel (BBT) project has reached another significant construction milestone with the successful completion of the concrete casting of a key intersection block within the tunnel system.

The intersection block is a highly complex underground structure that connects the central escape tunnel (Mittelstollen) with the main running tubes through cross passages. Its construction required extensive planning, innovative engineering solutions and close collaboration between the engineering and site teams.

To perform the concrete works without additional construction joints, a dedicated intersection formwork system was developed. Installed above the main tunnel formwork, the system creates a continuous casting arrangement capable of accommodating the unique geometry of the intersection structure.

One of the project's greatest challenges was the difference in elevation between the main tunnel and the cross-passage tunnels. The invert levels are offset by more than five metres, requiring the development and deployment of a specialised lifting and rotation system able to position the formwork accurately and safely at the required level.

Construction sequence

• Transportation of the intersection formwork onto the lifting platform.
• Lifting of the formwork more than five metres to the cross-passage level using the K-Vertex system.
• Rotation of the formwork by 90 degrees.
• Positioning of the formwork rings in their final locations.
• Removal of the lifting platform and the K-Vertex system.
• Installation of the escape tunnel formwork beneath the intersection formwork.
• Connection of both formwork systems to create the complete casting arrangement.
• Key project figures
• Combined formwork weight exceeding 300 tonnes.
• Individual intersection formwork weighing more than 70 tonnes.
• Vertical lifting operation of more than five metres.
• A total of eight intersection blocks to be constructed.
• Approximately 400 m³ of concrete placed in each intersection block.
• Continuous concrete pours lasting more than 24 hours.
• Deployment of four specialised machine systems: the KERN lifting platform, the intersection formwork, the transport gantry and the main tunnel formwork.

This achievement represents the peak of years of engineering development, innovation and close cooperation between all project stakeholders. It demonstrates the ability of the KERN team to overcome complex technical challenges while maintaining the highest standards of quality and safety.