Occasionally, an ironworker will need to “field-seat” a fixed-end anchor to an unbonded post-tensioning tendon. This may be required for the following reasons:
- Lack of stressing access on one side of a double-end stressed tendon.
- Incorrect tendon configuration at elevation differences (ex. parking ramps)
If an ironworker is in one of these situations, then they must use the proper equipment to safely affix the anchor to the strand. The ironworker will need the following post-tensioning parts:
- Tendon (PC strand with plastic sheathing taken off)
- Encapsulation accessories (if required)
- Hand-seating Tool
- Bearing Plate
- Detensioning Tool
- Stressing Equipment (calibrated jack, pump, gauge)
An ironworks who is certified in stressing post-tensioning tendons should be able to field-seat the fixed end anchor. Refer to picture above for the correct setup. The gauge pressure on the stressing equipment will the same as that for a normal stressing operation (at 33 kips). Also, the correct length of strand past the anchor is required in order to attach the yellow snap cap to end of the strand (see picture above with “encapsulated system – pull method”).
Failure to use the proper parts or equipment could result in damaging the anchor, strand, equipment or harming the operator/by-standers. This procedure should be carried out by a Post-Tensioning Institute Certified Ironworker (level 2).
– Neel Khosa, Vice President, AMSYSCO
Watch the Video: http://www.amsyscoinc.com/2012/08/01/video-field-seating-anchor/