DYWIDAG Twin-Corr Strand Anchor

Flexible installation with full double corrosion protection (DCP/Twin-Core) for extreme environments.

The DYWIDAG Strand Anchor System with twin concentric sheathing comprises two corrugated sheaths within the bonded length and individually greased and sheathed strands within the free length, housed within a common external sheath. This system is known as Twin-Core in Europe, but double corrosion protection (DCP) elsewhere.

There is a distinction between the national standards of Europe, UK and America. European Standards tend to accept a single corrugated sheath in the bond length and two plastic sheaths in the free length (strand sheathing within a common external duct) for permanent works in a range of ground conditions. For aggressive environments, European standards typically specify Twin-Core protection. In the UK and other countries using UK specifications, DCP is specified for all permanent works, irrespective of the environment. In America, different grouting systems are used, often pre-grouting the ribbed duct within the bore prior to installation of the tendon bundle, therefore a range of sheathing systems are employed

  • Concentric ribbed sheathing within the bond length ensures that there are two independent durable barriers between the tendon and the installation environment for enhanced protection

  • True double corrosion protection (DCP) over the full length of the anchor tendon to comply with national standards and ensure system longevity

  • Long lengths of up to 90m+ are available to suit multiple applications

  • Anchors are supplied as single section, and are fully coiled for ease of transportation and site handling

  • Particularly suited to low headroom or restricted access locations due to the flexibility of the tendon

  • Anchors can be grouted in-situ or supplied factory pre-grouted, dependent on site restrictions and grouting capabilities

  • Anchor head componentry can be tailored to specific applications, e.g. re-stressable or de-stressable

  • Anchor head protection for permanent works comprises specialist anchor protection caps and sealing arrangements to ensure a long service life

  • Load monitoring options and instrumentation can be incorporated with DYWIDAG Strand Anchor Systems for data-driven insights

Main standards for steel nuances

Europe/ Asia/ Latin America: Steel Strand Ø 15,2mm (0.6 in) and Ø15,7mm (0.62 in) – 1 to 22+ strands

UK: Steel Strand Ø 15,2mm (0.6 in) – 1 to 27+ strands

North America: 7-wire, low relaxation 270 ksi Steel Ø 0.6 in (15,2mm) – 1 to 61 strands


  • Bearing plates with angle compensation, different finishes, architectural features.

  • Borehole spacers : lantern or skid

  • Tremie tubes for borehole grouting (bottom up)

  • Post-grouting tubes complete with TAM (tube à manchette) valves for bond stress enhancement

Commercial & Residential Buildings