I have not checked lenghts I will do that and The design engineer has said to "It is to be based on elongations – tendons pulled to the specified elongations." But thanks I will look at the lenghts
at the calibrated psi we can only seem to get 1 1/4 to 1 1/2 inch of elongation we need another 1/2" to 1/8" to get to the 10% min of 1 5/8". So basiclly I should be pulling the the calibrated psi even if they are short.
The machine is calibrated correctly and pulling all other tenons on site well and the calculations check (elong = P * L / (E * A)) with other factors (Loss of prestress due to friction, elastic shortening, creep and shrinkage of concrete, and steel tendon relaxation)taken in to account...
the elongations values are in line with the other short tendons in the building 1 3/4 inch +/- 10% (which pull fine) for instance a 27 foot tendon in the building needs to be pulled 2 inches. I don't know about friction except that the tendons of similar length on the buildings pull fine at 5500...
I am working on a project and doing the elongation reports for a large apartment complex subdivision. All the building's tendons are tensioning fine at 5500 psi lengths from 14 to 100+ feet but when the garages are tensioned specifically the 23 foot long tendons they are needing nearly 6000 psi...
