AMSYSCO Post Tension Blog

PTI Certified Plant – AMSYSCO 2011

By admin, on June 18th, 2011

AMSYSCO, Inc. passed its first unannounced Plant Inspection in the 2011 calender. The certification program is overseen by the Post-Tensioning Institute.

“Certification of Plants Producing Unbonded Single Strand Tendons—Launched in 1989, the first program, Unbonded Single Strand Tendon Fabrication Facilities, is for facilities that fabricate unbonded single strand tendons. Since its inception, participation in the program has grown steadily. Fifty-five plants are certified, which represents approximately 95% of the industry’s production. In 2007, PTI added provisions to permit certification of mobile fabricating facilities in addition to fixed plants.”

(Source: http://www.post-tensioning.org/certification_program.php)

Related Links: AMSYSCO Certified Plant for past year’s certificates (1989-2009)

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Video : Stressing Unbonded Post Tension Tendon

By admin, on June 16th, 2011

This short video show the stressing an unbonded post-tensioning tendon with a hydraulic jack (8-inch stroke). This tendon was roughly 130 feet long so it required two strokes. The elongation for a 100-foot-long tendon is roughly 8 inches. Refer to the Post-Tensioning Institute’s “Field Procedures Manual for Unbonded Single-Strand Tendons” Chapter 6 for additional information.

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Video : Applying paint mark for Tendon Elongation

By admin, on June 16th, 2011

This short clip shows how to apply paint-marks prior to stressing of post-tension tendons. It’s recommended to use a straight-edge, metal to help with elongation measurements. Refer to the Post-Tensioning Institute’s “Field Procedures Manual for Unbonded Single-Strand Tendons” Chapter 7 for additional information.

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How do I know if my Post-Tensioning Tendons have been stressed?

By nkhosa, on June 16th, 2011

As a post-tensioning inspector or installer, have you ever been in a situation whether you are unsure whether some PT tendons have been stressed? By not having a PT tendon stressed, this could have detrimental effects on the structure.

Here are three pointers that may help you out:

1. PAINT-MARKS : Compare the location of the paint-marks to other tendons of the same length. If you see a major difference in one or more paint-marks, then the flag should go up. If the location of the paint marks are similar, then either ALL of tendon have been stressed or NONE of them have been stressed. If you have a deviation, then you may have an unstressed tendons or an elongation issue. (Related Video : Applying paint mark for post-tensioning tendon).

2. BITE-MARKS : Check whether there are “bite-marks” on the tendons. During the stressing operation, the hydraulic jack “grabs” the stressing tail of the PT strand and and creates a series of small bite-marks. The picture below shows two tendons that have been stressed (click picture to enlarge). This visual inspection helps if your paint-marks have been washed away.

Bitemarks into Post-Tensioning Strand

3. ELONGATION RECORDING : AMSYSCO highly recommends that the inspector (or testing agency) record elongation during the stressing operations…rather than several hours later. This step increases the quality control of the project and eliminates a potential unstressed tendon.

- Neel Khosa, Vice President, AMSYSCO

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