Hello,
Is there a resource/link/paper that shows the calculation method that PG Super is using to calculated the beam rotation due to prestressing? This value is reported in the Bearing Design Parameters report and there are extensive calculations of stresses and strains due to prestressing losses, but no direct link between effective prestress and rotation due to prestressing. At the root of my concern is whether shrinkage is wrapped into the prestress rotation that's reported, if it's wrapped into the rotation due to creep, or if it's left out.
Thank you.
PGSuper uses an internal 2D plane frame matrix analysis solver, but the beam rotations due to prestressing are equivalent to the closed form equations for cases 3 and 5 in Table 8.7-1 of the PCI Bridge Design Manual.
The beam rotation due to prestress is not adjusted for any time-dependent effects.
The creep rotation listed in the Bearing Design Parameters report is (girder + ps rotation)*(creep coefficient, initial to erection) based on the dead load rotations during storage, adjusted for any change in support locations at erection + (girder + ps rotation)*(creep coefficient, initial to deck placement - creep coefficient, initial to erection) based on dead load rotations after erection.