Issues in handling staged construction analysis for post-tensioned bridges

 

The behavior of pre-stressed concrete structures depends on the effect of pre-stress. When a pre-stressed concrete structure is analyzed, engineers must anticipate and correctly calculate the change of tensions throughout each stage of construction.

What highly-skilled engineers need is a feasible/efficient method to analyze the bridge model and extract tendon loss results while considering various factors that cause the loss, such as shrinkage and tendon relaxation before tensioning, elastic shortening and loading and temperature after tensioning.

Process and features helpful for checking constructability of Suspension Bridges

 

PrePost Process.png

Significant Features and Differences in Results

  1. Modeling Wizard: Excellent tool to accelerate the modeling process
    • Quick and easy tendon profile definition
    • Built-in construction stage feature within the wizard
  2. Tendon Profile: Flexible tendon profiling feature. 4 ways of defining tendons
    • Define your tendons within modeling wizard
    • Define your tendons directly from our Tendon Profile feature
    • Define your tendons by copying and pasting coordinate cells from excel
    • Customize your tendons in AutoCAD and import dxf file
  3. Construction Stage Analysis & Tendon Results
    • Detailed results for creep and shrinkage
    • Tendon Loss results
    • Tendon Stress Limit Check
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PROJECT APPLICATIONS


       TESTIMONIAL

PrePost Engineer 1 - Midkiff AECOM.png

I used Prestressed loads portion of the program to define the tendon profile. For me, defining the tendon in midas Civil’s manner is more intuitive. Nice thing about using this tool in midas, you can do all the calculation work in excel and copy the cells into the tool. Makes it easier for initial profile settings or if I want to adjust anything later in the design. With the use of the spreadsheets and ability to copy and paste into tendon profile tool, assignment to define all these tendons were greatly reduced, eliminating the redundant process

Doug Midkiff at AECOM Denver, co

PrePost Engineer 2 - Tony Ledesma WSP.png

Typically, you would use a special software like midas Civil to simulate the stage construction. Typical software packages don’t allow you to actually have separate models/structures joined together in a same model. So you need a special s/w to allow unconnected structures to account the time dependent effects and loading history on the structure.

 

Tony Ledesma at WSP