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Steel Combination Bolt

Immediate and permanent rock bolting solution

GEOTEC™ Steel Combination Bolt is suitable for the most stringent requirements. A mechanical bolt combined with a corrugated pipe and a double grout layer all along tendon to provide both high bonding and protection against corrosion (similar to Double Corrosion Protection / DCP).
It is initially installed for immediate support by the use of an expansion shell, to be fully grouted at a later stage allowing it to be classified as permanent application.

Product features

Shell range

Available for every ground

Various applications

Such as roadways, hydropower
and underground oil/gas storage,
sub-sea and sewer tunnels

Instant support

Once expanded, the shell and rod
provide a full anchor, letting you
continue the excavation right away.

Related Projects

Hatta Pumped Storage Hydro Power Plant

Hatta Pumped Storage Hydro Power Plant

The Hatta Pumped Storage Hydro Power Plant project will use water stored in an upper reservoir, utilizing pumped storage technology. Dextra was involved in the excavation of the hydro tunnels by supplying thousands of GEOTEC™ steel bolts.

Melbourne Metro: five new underground stations

Melbourne Metro

This Melbourne Metro extension features a 9 km long tunnel and five new underground stations. Dextra Griptec, Astec Combination Bolts, Astec Soil Nails and Soft-Eyes were selected for the construction of this project.

Zakhr City

Zakhr City

Zakhr City is one of the largest real estate projects in Mecca, Saudi Arabia. This mixed-development project consists of three to four-star hotels, residential towers as well as markets, health centers, police and fire stations. It is designed to accommodate more than 200,000 people.

Related solutions

Specific tunneling application of GFRP rebar cage allowing a TBM to break through a reinforcement cage in a minimum time.

Soil Stabilization: Fully cut-able FRP soil nail system used for the stabilization of slope.

Soil Retention: Post-tensioned steel ground anchor system used in excavation works.


At every moment of your customer journey, Dextra teams dedicate themselves to the production of smart construction solutions that allow our customers to reach higher productivity and safety levels on their construction sites.

Dextra holds physical stocks on several continents, complemented in each country by the local inventories of our distributors. With this extended network, Dextra makes sure our products are always at reach no matter where our partners are.

For solutions that require to be customized, Dextra can also go beyond our standard delivery times and offer accelerated delivery schemes. Consult us for more information.

From 3 major industrial sites located in Bangkok (Thailand), Guangzhou (China), and Pune (India), Dextra completely owns its manufacturing facilities and processes. This allows us to have complete control over the timing of our operations and the quality of the solutions produced.

An independently accredited material testing laboratory, accredited to ISO-IEC17025, is located at Dextra’s main Bangkok factory, allowing the testing of material and products.

Dextra aims to supply products that exceed the most demanding international technical approvals and it is our goal to create maximum customer satisfaction by complying with our clients’ needs and specified requirements.

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