Debonded Strands in Pretensioned members

The de-bonding of the strands in the midspan could be done using same methods as for ends of the beams i.e. by sheathing or greasing. Typically this is being done with the top strands, and pockets should be left for cutting the strands prior to the release.
In case when sheathing is used, the unused (unstressed) sections of strands could be grouted after cutting to be used as part of reinforcement.

wiktor

I agree that this is the only way to do it to achieve what is referred to as debonded strands in pretendioned members. It is not sufficient to simply debond the strand as would be the case with unbonded post-tensioning, it must be released/cut also so that there is no force in it over the debonded length from the stressing operation.

The regrouting would not be all that effective as there would be a significant development length either side of the cut.

I was wanting to make sure that people using internal debonding realised that it involved more than simply greasing the strand to ensure that it was not bonded to the concrete. That the term "debond" in pretensioning means no pretension force in the strand and that it needed to be specified properly.