Bolting Systems

Tunnel segment bolting systems connect precast concrete segments during tunnel construction, including radial joint, segment to segment and circumferential joint, ring-to-ring connections.

Selection depends on your segment design, ring geometry and loading conditions. Our engineering team works from your project specification to recommend the right grade and socket combination.

We supply bolting systems for both radial (segment-to-segment) and circumferential (ring-to-ring) tunnel segment joints, in carbon and stainless steel with plastic or stainless socket options.

Sockets are available in PP, ABS and PA+FG plastic materials, as well as stainless steel. The appropriate option depends on the installation method, service requirements and project specifications.

Carbon steel is the primary supply material, with Grade 10.9 available for applications requiring higher tensile and shear performance. Other grades and materials can be considered according to the project specifications.

Socket lengths range from 80mm to 175mm, allowing the system to be configured around different segment and recess requirements.

Yes. Alongside bolting systems, we can supply associated components including dowel systems, guiding rods, grouting and lifting systems, marking plates, radial coupling and shear cones as part of a broader tunnel segment package.

Dowel systems are faster to install and hold tighter tolerances, while bolting systems remain the standard, dependable choice across most tunnel packages.

OPTI.Fix® provides a more efficient method for fixing sockets within segment moulds, helping save time during installation and demoulding while reducing maintenance and supporting improved production consistency and automation.