Dextra America, Inc. -Ground Engineering - Tunneling & Mining - ASTEC™ FRP Combination Bolt


ASTEC FRP Combination Bolt is a unique and innovative GFRP solution precisely designed by Dextra.

Category: mining | mining equipment | tunnel bolts...

MasterFormat: Tunneling and Mining | Tunnel Construction

Dextra America, Inc.
10317 SE 273rd PL
Kent, WA 98030
Tel: (206) 742-6020

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Ground Engineering - Tunneling & Mining - ASTEC™ FRP Combination Bolt

Innovative FRP solution for efficient tunnel excavation

ASTEC™ FRP Combination Bolt is a unique and innovative Glass Fiber Reinforced Polymer solution precisely designed by Dextra.

In unconsolidated excavation areas, like steel bolts, FRP Combination Bolt can be automatically installed by jumbo machine or manually installed.

Thanks to the characteristic of the FRP material, Combination Bolt can easily be cut by common excavation equipment, which makes the product an ideal solution for temporary application for tunnel excavation projects.

Product Features
  • Recommended for borehole diameter 43-45mm.
  • FRP profiles are twice as strong as steel in tensile strength, for only 25% of its weight.
  • Tensile strength up to 1,000 Mpa.
  • Thanks to its metric metal nut, the number of rotations is similar as steel bolts. During the installation, the operator will not notice any difference when pre-tensioning the bolt.
  • Clearance inside the tunnel is maximized due to its short tail length. This also limits the concrete lining thickness if the head have to be embedded.
  • Compatible with automatic grouting process.

Corrosion free : Resistant to both acidic and alkali environments.

Cuttable systems : Can be easily cut by common excavation equipment.

Light weight : Easy handling, transportation and installation inside the tunnel.

Cut-able solutions

Cut-able support is mostly used in the longitudinal direction of the tunnel (portal, face) when temporary stabilization is required before moving to the next phase. Also, Mechanized Tunneling is becoming standard in urban areas, especially for underground metro projects. This modern technique is calling for new kind of systems, in particular cut-able reinforcement bars for concrete structures (like Soft-Eyes in D-walls) and cut-able ground anchors.

Radial & lateral support (Roof & Wall)

When building a tunnel by drill & blast or conventional mining, the roof and walls need to be supported. Rock-bolts are the first type of support installed, before any other kind of mesh or lining is applied. Depending on the construction sequence and technology, both temporary and permanent bolts can be offered.

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