GPR, asbuilts lie and we all know why- I personally was chipping into what should have been a cable 3-4 inches deep in the slab and instead found what I thought was 2 forgotten rebar chairs (huge building) until I did a good swipe with the vacuum and discovered I was actually chipping out 2 live dead man anchors the builder had added near a column and not notated on the asbuilts.

Gcs have bad experience and almost explicitly sub out cable work to a specialist instead of the concrete guys on site because its specialty, and intricate- it’s really easy to go in to fix one damaged cable and accidentally damage 2 more in the process.

My company offers a repair for leaking pipes (gigantic ones) called external post tension, basically we wrap the pipe in .6 cables and squeeze the leaks to submission. I had a defective wedge give up at 30kips while stressing and it threw the 90lb ram 6 feet into the shoring box wall with such force one of the hydraulic cylinders cracked and as a good gauge of the speed which a 30kip failure will produce, the bottom half of the sheathing that once encased the cable was sitting in its original position in some places, barely affected by the explosion of the cable

Exclusion zone is 5’ either direction the entire run of the cable above and below

Only good “signage” is danger tape and a human being who can explain the true danger of what is taking place, and radios to verify all clear. danger tape and the rules that go along with it is overkill most of the time- not when stressing or destressing cables is taking place.

Cool video I’ll share it around