Freyssinet invented the prestressing, which was a revolution in civil engineering. Our C range offers a solution combining performance and durability for all types of structures.

Post-tensioning kits under European Technical Assessment

The post-tensioning kits marketed by Freyssinet are CE marked in accordance with the European Technical Assessment, which ensures product performance, quality control, and state-of-the-art installation methods.

Freyssinet supply the post-tensioning kits components to compose tendons for internal or external prestressing cables with passive and active ends (anchorage blocks, jaws, caps), as well as the parts embedded in concrete such as trumplates, ducts, couplers when needed.

Others components are sourced according to applicable standards:

  • Metallic or plastic ducts
  • Steel or smooth plastic pipes
  • Prestressing strands
  • Tendon filling material

Prestressing steel corrosion protection is essential for the durability of the post-tensioning tendons. It is provided:

  • by a high-quality cement grout and a careful injection for bonded prestressing,
  • or by multi-layer protection given by individually sheathed and greased strands combined with cement grout injection after stressing in the case of unbonded prestressing technique,
  • or by filling the duct by wax for external (unbonded) prestressing tendons composed of bright steel strands.

Tensioning kit

Choosing expertise and service

The C-range is the Freyssinet state-of-the-art prestressing solution for civil engineering. Optimized for every application, it complies with the most stringent requirements in terms of performance and durability.

Post-tensioning teams

The C range anchorage blocks are the smallest component of all existing prestressing kits, allowing to significantly reduce the size of the embedded trumplate in the concrete. Their surface area is 60% smaller than the traditional PT system using a bearing plate, allowing to:

  • reduce the width of the beams and webs of the concrete box girders
  • increase the distribution of the prestressing tendons
  • reduce the distance from the concrete edge

Freyssinet C-range system is used to compose prestressing tendons units from 3 strands (GUTS: 837 kN) to 55 strands (GUTS: 15345 kN).

15 mm (15.3 or 15.7) strands of all steel grades (up to 1860 MPa) in bright steel or individually greased and sheathed strands.

The C-range was developed by Freyssinet 30 years ago. It has been continuously improved and adapted since then to suit the projects’ needs worldwide.

Expected lifetime of 100 years.

Thousands of applications worldwide.

The prestressing system allows to provide PL1/PL2/PL3 protection levels as defined in fib bulletin 33.

Certificate of Constancy of Performances No 1683–CPR–0048 described in ETA No 06/0226

By choosing Freyssinet, you will collaborate with a PT specialist, that can provide design services, in-house manufacturing, testing and site installation, or only expertise and knowledge where you need it.

Technical configurations

/ Bonded internal prestressing

This is the most common application. It is based on the use of an uncoated strand (bare steel) in a corrugated metal sheath and injected by cement grout.

Depending on project requirements, different configurations can be chosen, such as:

  • the use of a corrugated plastic sheath for aggressive environments,
  • Liaseal® duct coupler for precast concrete structures,
  • full encapsulation systems for electrical isolation.

/ Unbonded internal prestressing

Unbonded prestressing tendons offer multi-layer protection against corrosion. They allow the prestressing force to be measured, adjusted if necessary and the tendons to be de-tensioned or replaced if required.

When using bare strands, the injection material is usually wax.

The use of individually greased and sheathed strands contained in HDPE pipes, which are injected with a cement grout before tensioning, increases the durability of the prestressing tendons.

/ Unbonded external prestressing

External prestressing is well suited to thin concrete structures; it also allows easy inspection of tendons.

The most common application is based on the use of strands placed inside thick sections of HDPE pipes, mirror-welded and injected with cement grout.

To allow tendon removal, the ducts pass through a recess or a double casing at the anchor diaphragms and deviators.

Two solutions are commonly used to increase durability:

  • Use of individually greased and sheathed strands placed in a plastic pipe injected with cement grout before tensioning.
  • Use of bare strands placed in a plastic pipe injected with wax after tensioning.

Products supplied by Freyssinet

Compact anchorages

Active or passive anchorages consist of cast iron trumplates, anchorage blocks, wedges and plastic or cast-iron injection caps.

They are used to compose external or internal tendons, with bare or greased strands and HDPE sheathed strands, from 3 to 55 strand units (from 837 to 15 345 kN GUTS). They are implemented with an additional length of strands at the tensioning end.

Different functionalities are possible: encapsulated, electrically insulated, replaceable, retensionable.
  • Wide range of civil engineering applications,
    including cryogenic use
  • Expected lifetime of 100 years
  • Any protection level
    as required by the project specifications

Dead end anchorages

They are installed at the end of a tendon in areas that are not accessible after concreting. This implies that they must be carefully installed before concreting, in order to minimise the risk of strand slippage during tensioning.

Three types of dead-end anchorages are possible, depending on the number of tendons, units, construction sequences and local standards (1) Anchorage block with cylindrical holes and swages at strand ends, held in position by a retaining plate (2) Steel plate with cylindrical hole(s) and swage(s) at strand end(s) (3) Dead-end anchorage obtained by deforming the 7-wire strand into an “onion” shape.
  • For areas not accessible
    during stressing phase
  • Specific provisions to be taken
    when installing the system


The couplers connect two tendons which are tensioned one after the other after two separate concreting phases.

For multistrand coupling, they are made of machined steel with two sets of opposing conical holes.

A cast-iron model is available for the individual coupling of each strand.
  • Allows a PT tendon to be lengthened,
    depending on the construction phases
  • Single-strand couplers (with anchorage blocks)
    or multi-strand coupler can be used as fixed couplers
  • Single-strand mobile couplers are used for
    the strands that make up the tendon extension

LIASEAL -Seal system for match-cast segments

The construction of a segmental bridge involves assembling the post-tensioning duct segment by segment.

The Liaseal system is a duct coupler that ensures the continuity of the duct between the match-cast segments.
  • Coupler for corrugated plastic duct
  • Full encapsulation of
    the prestressing steel (with plastic duct)
  • Can be used for electrically-insulated tendons

1F15 anchorage for single strand prestressing needs

It allows the anchoring of a single-strand cable in thin civil engineering elements, such as bridge decks for transverse post-tensioning.

The cast-in anchor unit combines the function of an anchor block and a prestressing force diffusion plate.

It is particularly suitable for unbonded internal prestressing configurations.

1F15 anchorage for single strand prestressing
1R15 anchorage for single strand additional prestressing

1R15 anchorage for single strand additional prestressing

See the repair section of the website for detailed information.

1X and 2X anchorages for additional prestressing of circular structures

See the repair section of the website for more detailed information.

These are specific anchorages for the active strengthening of circular structures such as silos, tanks, chimneys, cooling towers and pipes. These anchorages consist of post-tensioning cable hoops that apply pressure to the structure to be reinforced.

The hoop anchor consists of a cast iron element resting on the circular structure and serving as an anchorage at both ends of one or two hoops:

  • The 1X anchorage is used to make a prestressing hoop on a structure with a radius up to 27,5m.
  • The 2X anchorage is used to anchor 2 hoops, each wrapped once or twice around the structure with a radius of up to 5.5m.

The system is suitable for unbonded external prestressing configurations (strand greased and sheathed in HDPE duct, grouted with cement before tensioning)

1X15 anchorage for additional prestressing of circular structures

Our references

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