Precast/Prestressed Girder Help

Automatic Straight Strand Pattern Generation

First, select the Straight Strand Pattern option on the Materials tab and then click the Auto Design button on the Strand Pattern (on the Beam tab). Precast/Prestressed Girder will generate a straight strand pattern. The following algorithm is used:

  1. The critical locations are found where the total final bending moment is maximum under both service and ultimate conditions. For the location of maximum positive service moment, the minimum number of required strands that will keep the tension stress at the bottom of the beam within the allowable is calculated.
  2. For the location of maximum positive factored moment, the minimum number of required strands that will make the required ultimate capacity less than the provided (Mu-reqd < Mu-prvd) is calculated.
  3. Precast/Prestressed Girder then takes the maximum number of strands from the above two conditions as the required number of strands.
  4. The top strands are raised as far as possible while staying within the allowable values in the above two conditions.
Parent topic: AASHTO LFD