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AMIJACK GRP jacking pipes are centrifugally cast pipes made of polyester resin, glass fibre and silica sand. The raw materials are fed into a rotating mould in specified amounts in order to form a layered composite structure with a compact construction. The raw materials are precisely metered by a special feeder which adds the various materials in accordance with the design formula of the pipe being produced. This process creates a very compact composite structure, which is necessary and very important for jacking applications. The unique wall construction ensures the proper and safe use of pipes at the time of installation and during later operation.

AMIJACK pipes meet all the criteria of the EN-ISO 25780 standard, thus ensuring excellent quality and precision of workmanship. Amiantit’s quality system imposes specific procedures at every stage of pipe production from raw material control, through pipe production and ending with tests on the finished product.

The pipes are designed for the construction and renovation of underground pipelines using trenchless methods. They feature high ring stiffness and a coupling design in which the outer diameter is similar to the outer pipe diameter.

AMIJACK pipes are delivered in outer diameters between 427 mm and 2,453 mm. They are offered in standard lengths of 1, 2, 3 and 6 m. Other lengths are available on request. In addition, the pipes are available with different kind of couplings.


As a GRP pipe, the AMIJACK product offers similar general benefits as already described for the Flowtite product. In addition, the unique material processing also offer some specific advantages and benefits for the jacking use. The main benefits of pipe jacking compared to open trench method are:

  • Minimum environmental disturbance, especially in urban areas
  • A strong, watertight, complete pipeline after jacking is finished
  • Usually low installation costs compared to open trench technology
  • Pipe structure can be designed individually according to project-specific requirements
  • High axial compressive strength (min. 90 N/mm2)
  • Smooth and even outer surface
  • Elastic material behaviour
  • Easy pipe machining
  • Low specific weight of GRP material
  • Excellent hydraulic characteristics

Material properties

Specific weight of material: 20 kN/m3
Longitudinal compressive strength: 90 MPa
Safety factor for jacking force 3.5
Colebrook-White coefficient: 0.01mm
Hoop flexural modulus: 11.000 MPa

The available standard ring stiffness SN (N/m2) with flush couplings varies between SN 32000 and SN 1000000.


AMIJACK pipes are used in pipeline construction for the transport and storage of water, rainwater, sewage and industrial wastewater. The pipes will be installed primarily by jacking and find its use predominantly in:

  • Construction of new sewer pipelines
  • Old sewer replacements
  • Construction of channels as protective tubes for gas pipelines, heating pipelines, etc.
  • Road and technology culverts in transport engineering
  • Electricity and telecommunication cable ducts in urban areas or areas with groundwater restrictions
  • Relining

More information on AMIJACK products is available here.