There is some chance that some post-tensioning tendons in a slab are misaligned. Could this be due to the impact of the concrete at the time it is placed?
There are a number of ways for tendons to get out of alignment, and some of these can occur before concrete placement begins. For this reason it is necessary to check alignment at all critical locations such as the midspan and inflection points of the slab before doing any concreting. Horizontal as well as vertical alignment should be checked. In placing concrete care should be taken not to change the position of either the tendons or the reinforcing steel. It is wise to have one worker assigned to maintain proper alignment just ahead of concrete placement. No concrete should be allowed to enter sheathing, anchorage hardware or pockets.