UNBONDED TENDONS: WHY THE FALL FROM FAVOUR?

Plastic sleeved tendons, developed as a refinement to external prestressing appeared to have many advantages when first introduced. However, broken strands were discovered in Bournemouth's Braidley Road Bridge within a year of its opening, caused by using an aluminium coating for protection rather than grease. Examples are given of the successful use of cables of similar design, but protected by grease, within polypropylene sleeves. The author believes that many other factors, besides the production of acidic byproducts by pvc during its decay contribute to corrosion, and considers the general ban on the use of unbonded tendons to be unjustified. Although conditions are different, the Central Electricity Generating Board has used specially developed grease or wax to protect unbonded tendons in its concrete reactors. It is suggested that, provided cables are protected during transit, there is little possibility of water getting into them.

Media Info

  • Features: Photos; References;
  • Pagination: p. 21
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00314537
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Dec 30 1980 12:00AM