Cast-in gaskets (also known as anchored gaskets or cast in situ gaskets) are integrated with the segment during the casting process.
This is opposed to being glued into a pre-made groove once the concrete segments have been cast.
Cast-in seals ‘anchor’ themselves to the segment as the concrete surrounds the legs at the base of the seal.
This process ensures a consistent positioning of the gasket around the segment.
The design of the legs ensures that the seal is secure in the segment and will not move during or after the segment is cast.
This is especially important during installation of the tunnel segments.
Benefits of Cast-in Gaskets
- No need to apply adhesive
- Cleaner to work with
- Provide cost savings due to the removal of adhesive and the gluing process.
- A more secure fit in the segment leading to reduced movement of the seal during installation and increased performance
UNIQUE CORNER JOINTING SYSTEM
No Solid Corners
Cracked or damaged segments caused by corner point loading has traditionally been a problem faced by tunnelling engineers and designers.
VIP’s Cast-in gaskets are designed specifically to eliminate this due to the unique patented (GB2541978 – international patent pending) corner jointing system.
This has allowed us to dramatically reduce the volume of rubber at the corners, thus ensuring the gasket can collapse into the groove and the load on the corners is equal to the rest of the gasket.
MINIMISING RUBBER VOLUME AT THE CORNER JOINT
VIP’s unique jointing process results in the profile of the gasket being maintained up to the corner edge. This ensures that the compression performance of the gasket is equal along the entire face of the gasket.
This differs to a traditional shot-joint corner which can result in excess rubber travelling along the gasket voids during the moulding process.
This results in making the gasket unable to compress at the corners due to the voids being full of rubber, creating a ‘solid’ corner.
The energy exerted at these points during closure of the segments can lead to cracks and spalling as it dissipates through the segment, finding the path of least resistance.
CORNER ANGLES THAT PERFECTLY MATCH THE SEGMENT
VIP can manufacture corners for cast-in gaskets to obtuse, acute and 90° angles, therefore matching the profile of the segment design perfectly.
|Z Axis Angles|
Segment design can differ with each project. Recognising this and the importance of the gasket matching the exact shape of the segment.
VIP can also vary the profile orientation along the Z axis.
The following profiles comprise VIP’s cast-in core range.
Further profiles are available or can be developed on request to meet specific design requirements.