Fibre Reinforcement for Tunnels
Our fibres reinforce sprayed, cast and precast segment tunnel linings.
Macro Synthetic Fibre Reinforcement for Tunnel Linings
BarChip macro synthetic fibre provides reinforcement for shotcrete, precast segments and cast in situ concrete, creating fibre reinforced tunnel linings that offer a proven alternative to steel mesh, steel fibre and steel bar reinforcement.
Distributed throughout the concrete, BarChip fibres provide residual strength and toughness while eliminating corrosion. By reducing or replacing conventional steel reinforcement, BarChip can simplify construction, improve worker safety and significantly reduce the embodied carbon of tunnel reinforcement.
BarChip Fibre Reinforced Tunnel Projects
Fibre Reinforced Precast Segmental Linings
BarChip macro synthetic fibre provides effective post-crack reinforcement for precast tunnel segments and can be used as the sole reinforcement or in combination with conventional steel.
Full scale segment testing has demonstrated effective stress redistribution and sustained load carrying capacity as cracking develops. By reducing or eliminating steel cages, BarChip can also simplify segment production, reduce reinforcement handling and improve manufacturing efficiency.
Fibre Reinforced Shotcrete Tunnel Linings
BarChip macro synthetic fibre provides toughness and ductility in temporary and permanent shotcrete tunnel linings, allowing the lining to continue absorbing energy and carrying load as cracking and deformation develop.
For shotcrete ground support, this ductile response allows the lining to accommodate ground movement and deformation while maintaining reinforcement throughout the shotcrete. Mechanised application also reduces the need for workers to operate beneath unsupported ground, while corrosion free reinforcement provides long term durability benefits for permanent linings.
Cast In-Situ Linings
BarChip macro synthetic fibre can be used as the sole reinforcement in cast in situ tunnel linings or in combination with steel or GFRP reinforcement, providing designers with greater flexibility in the reinforcement system.
Where BarChip is incorporated into the primary lining, load sharing between the primary and final lining can potentially reduce the required thickness of the final lining. Further reductions may be possible where additional concrete cover would otherwise be required to protect conventional steel reinforcement from corrosion.
Invert Segments
BarChip macro synthetic fibre can reduce or eliminate conventional steel reinforcement in precast tunnel invert segments, simplifying reinforcement and accelerating the manufacturing process.
With fibres added directly to the concrete mix, there is less reinforcement to fabricate, handle and position before casting, helping reduce production time and labour while providing corrosion free reinforcement throughout the finished segment.
Slope Stabilisation
BarChip macro synthetic fibre is used in shotcrete for slope stabilisation, providing distributed reinforcement throughout the sprayed concrete layer without the need to install steel mesh across irregular ground surfaces.
Fibre reinforced shotcrete can be applied directly to the prepared surface, simplifying reinforcement installation and reducing the time workers spend operating on exposed slopes. Corrosion free reinforcement also provides long term durability in exposed environments.
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BarChip Fibre is reinforcing more than 500 road, rail and utility tunnels around the world.
Low Carbon Tunnel Linings
BarChip macro synthetic fibre can significantly reduce the embodied carbon of tunnel reinforcement by replacing much heavier conventional steel reinforcement systems with a comparatively low dosage of synthetic fibre.
Further carbon reductions can be achieved through reduced transportation, shorter construction times and opportunities to optimise lining thickness and concrete consumption. Together, these benefits can reduce embodied and construction related carbon across the tunnel lining system.
The Trusted Fibre for Tunnelling
For more than 30 years, BarChip macro synthetic fibre has been used on major tunnelling projects around the world, delivering proven performance across a wide range of ground conditions, tunnel designs and construction methods.
Designed to International Standards
BarChip macro synthetic fibre reinforced concrete can be designed and tested in accordance with internationally recognised standards and established design methodologies, providing engineers with defined performance parameters for tunnel lining design.
Project Highlights
Frequently Asked Questions
What type of tunnels does BarChip fibre reinforce?
BarChip macro synthetic fibre has reinforced more than 500 civil tunnels, including road and rail tunnels, water and electrical utility tunnels, hydroelectric, pedestrian, storage and service tunnels.
Where are macro synthetic fibres used in tunnelling?
BarChip fibre is used to reinforce temporary and permanent sprayed concrete tunnel linings, cast linings, segmental linings, invert segments and slope stabilisation works.
How is fibre reinforced shotcrete performance measured?
Fibre reinforced shotcrete is commonly assessed by its ability to absorb energy and maintain load carrying capacity as cracking and deformation develop. Performance requirements are typically established through recognised panel or beam testing methods.
How is fibre dosage determined for tunnel linings?
Fibre dosage is determined by the required structural or ground support performance, concrete mix and applicable design methodology. Performance testing is used to verify that the selected fibre and dosage achieve the specified requirements.
Why are synthetic fibres used in tunnel construction?
BarChip macro synthetic fibres eliminate corrosion, improve toughness, reduce construction time and cost, improve safety and lower the embodied carbon of tunnelling works.
Can Macro Synthetic Fibre replace steel in tunnel segments?
Yes, BarChip macro synthetic fibre has reinforced the segmental lining in multiple projects, both as the sole reinforcement and as a composite with a reduced volume of steel.
How do fibres improve the safety of tunnelling works?
Fibre reinforced shotcrete can be mechanically applied without installing steel mesh, reducing the need for workers to operate beneath unsupported ground during the excavation and support cycle.
Does BarChip fibre reduce the carbon footprint of tunnelling works?
Yes. Comparatively low dosages of BarChip macro synthetic fibre can replace much heavier conventional steel reinforcement systems, significantly reducing the embodied carbon of tunnel reinforcement.
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