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. Service results are used to find the location where the maximum total final bending moment is maximum. At this location, the program calculates the minimum number of required strands that will keep the tension stress at the bottom of the beam within the allowable margins (calculated or user-modified).
  2. The envelope of Strength results is then used to find the location where the total final bending moment is maximum. At this location, the program calculates the minimum number of strands that will make the required ultimate capacity less the provided ultimate capacity (Mu-reqd < Mu-prvd).
  3. Then, the program adds the maximum number of strands from Step 1 and Step 2 and uses it as the required number of strands.
  4. The program then starts raising the top strands as far as possible while staying within the limiting stresses for the two conditions.
Parent topic: Theory