Kink in a Tendon

On rare occasions, the installer will unroll a tendon that looks like this…

Kink in Tendon

WHAT WILL HAPPEN?

During the stressing operation, this tendon will probably break due to the eccentric force at the anchorage. Chances are that this tendon would break well before the required 33 kips is applied. Not only would this become a safety issue, it will eventually become a repair issue when the tendon breaks. That is time, money and aggravation that can be avoided.

HOW TO FIX IT?

I do not recommend stressing this tendon at a lower force. The question is what do you do to fix or repair a “kink” in an unbonded post-tensioning tendon?

  • Option #1 : Replace the tendon with a new tendon.
  • Option #2 : Cut off the dead anchor and field-seat a new anchor. Make sure you have enough stressing tail after cutting the anchor.

WHY DOES IT HAPPEN?

Why does this happen? During loading, transit or unloading, this anchor had some “extra” load applied to it and caused the tendon to bend or kink. When the kink is relatively far away from the anchorages, then the kink probably occurred due to a power surge in the manufacturing equipment. This issue can happen if the tendon bundles have the eye-to-the-sky or eye-to-the-side.

-Neel Khosa, Vice President

Related Articles: Field-Seating Anchor

Photo Credit:  Adam Lynn, Fort Wayne Reinforcing

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