LRFD specifications section 5.10.10 requires that vertical
reinforcement be placed in pretensioned anchorage zones
(the end region) in sufficient quantity to resist a force equal
to 4% of the prestressing force from fully bonded strands.
Stress in the reinforcement is limited to 20 ksi (140 MPa),
and it is placed as close to the end as practicable. These
requirements are to be applied at the service limit state