TO: All Design Section Staff FROM: J. Kapur DATE: July 17, 2002 SUBJECT: Calculation of Shipping Losses in Prestressed Girders
Prestress losses at release, lifting, transportation, and erection of prestressed girders, and the final elastic and time dependent losses shall be as follows:
We have recently added trapezoidal open box beams (U-beams) to our precast girder inventory. The prestress losses for these sections are significantly less then the losses for our conventional I-beam sections. The lump sum shipping loss of 35 KSI is not appropriate for the U-beams. In some cases, the 35 KSI shipping loss can exceed the computed final loss. To remedy this situation, while keeping the method of estimation simple, shipping losses will now be taken as a fraction of the final loss.
Contact Rick Brice at 705-7174 or Bijan Khaleghi at 705-7181 for questions regarding this change.