Unbonded Internal Post-Tensioning

Bridge maintenance and inspection is made easy with DYWIDAG unbonded internal post-tensioning. 

DYWIDAG unbonded internal post-tensioning systems are strong, reliable, and corrosion-proof. Systems can use mono-strand tendons, wire tendons, strand tendons, and DYWIDAG Threadbars™.

Unbonded internal post-tensioning systems are used as

  • Mono-strand tendons: Bundled, greased, and PE-sheathed mono-strand tendons are typically applied in the construction of buildings—and used in the transversal post-tensioning of bridges

  • Internal wire tendons: Typical applications for internal wire tendons include bridges and other civil structures that consist of solid cross-sections, or slabs where there is a need to check the stressing level at a later stage

  • Unbonded strand tendons: Typical applications for unbonded strand tendons include bridges and civil structures.

  • DYWIDAG Threadbar™: Unbonded internal bar post-tensioning systems are used in projects where infrastructure needs strengthening and repair. Typical applications include the connection between precast members, the fixation or tieback anchorages of steel structures—and transversal post-tensioning.  


  • Strand systems up to 55 strands and monostrand systems

  • Bar systems up to diameters 47mm

  • Wires systems up to 84 wires

  • Corrosion protection is usually prefabricated with the tendon, delivered to site, and installed 

  • Soft corrosion-protection compound such as grease, wax, or gel

  • Low induced stress range 

  • Less fretting fatigue 

  • Monitoring of stressing forces 

  • Restressing possible, if required 

  • Replaceable, if required 

Commercial & Industrial


Stadiums & Arenas


Silos & Tanks

Nuclear Power

Cast-in-place Method

Immersed Tunnels

Tunnels Using Cut-and-cover Method