Post-tensioned cable propertyDescription
Modules where available1585056654158-405.png  1585056661203-274.png
FunctionIt is a structural component, modelled by equivalent load system.
Axis positionArbitrary (horizontal, vertical and skew)
ShapeWavy with Base points and Inflection places
  • Radius of curvature
  • Angular deviation
  • Stress function with friction losses
  • Stress function with anchorage set slip losses
  • Stress function with elastic shortening losses
  • Stress function with all time dependent losses
  • Equivalent force for 1 strand
  • Equivalent force for PTC
Manufacturingthe Manufacture drawing can be set with proper x’ and z’ shift
Default Short CommandBPTC

Table: Post-tensioned cable properties

Definition steps

  1. Start 1585056675018-687.png Post-tensioned cable for bars/Post-tensioned cable for shells command from 1585056682723-706.png tabmenu and pick the parent object (a bar or a shell), then define the line of the PTC.
    The two Tool window work in slightly different ways: for shells, the user can define more cables by using Line by selection option, but for bars only one cable can be defined.
    1585056703036-181.png 1585056708351-713.png

    It is strongly recommended to use Axes: all aid functions (Macros, Shape wizard, Layout wizard) highly rely on them. It could greatly speed up the definition process.
  2. Click 1585056791005-884.png  Default settings and set the properties of the PTC
    • Identifier (General)
      The program automatically generates it, but you can define custom value. Identifier (ID and Position) number can be displayed in model view (Display settings).
    • Strands (General)
      User can set the type from the strand library and the number of the strands by typing.
    • Jacking (General)
      User can select the Jacking side in the drop-down menu next to Jacking side. Jacking side options: Start, End, Start then End, End then Start. The last two are Both-sided jacking with same stress, but it was necessary to distinct, because the effect of draw-in could result in different stress functions using shorter cables.
      Jacking stress is calculated as 0.8 * fpk by default after the Strand type selection.
    • Short term losses (General)
      • friction: It is estimated by EN 1992-1-1 (1) (formula 5.45) using the Wobble (k) and Curvature coefficients (µ):
      • 1585056921812-564.png
      • anchorage set slip
      • elastic shortening
    • Long term losses (General)
      • shrinkage of structure
      • creep of structure
      • relaxation of post-tensioned cable
    • Shape
      There are settings related to the geometry of the cable (Display settings) here. The Shape table can contain Base points and Inflection places: these determine whether linear or parabolic shape is applied.
      The Top and Bottom values mean the distance between the axis of the cable and the edge of the element.
      Using Shape wizard (Shape wizard… button) parabolic shapes can be easily created. This tool highly relies on previously defined axes.
    • Results
      There are several results -listed in the order of calculation - which can be chosen from Result tab/Result drop-down menu.
    • Manufacturing
      On this tab the Manufacture drawing can be set with proper x’ and z’ shift.

Optional steps:

  1. Modify the PTC properties with the 1585057015546-777.png  Properties tool of the Post-tensioned cable bar/shell tool palette.
  2. Set the display settings of PTC elements at Settings > All > Display > Post-tensioned cables.
  3. The PTCs are stored on “Post-tensioned cable” Object layers. At layer settings, the default color and pen width can be set for all PTC elements. The color and pen width settings by selected PTC elements can be modified by Edit > Properties > Change appearance.

Layout wizard

It is a tool to create a set of PTCs in a specific layout. It can be launched from Structure/Shell component/Post-tensioned cable/Layout wizard.


The Layout wizard searches for the closest solution to the Unequal loading settings from the PTC layout variations which fulfilled the following conditions:

  • difference between the sum of the PTC’s forces acting in local z+ direction and the product of Considered load and Balance ratio is less than the Maximal deviation
  • geometrical requirements

The Layout calculation process shows the currently calculated layout parameters and a few indicator values. After the calculation it shows the parameters of the best found solution.


The function uses Axes to divide the selected structural element to stripes (Mid span and Column span) assuming columns in the axes cross points.

1585057125352-192.png  1585057129579-924.png

The algorythm can handle the holes of the plate regions.

warning.pngAt least two Axes crossing the plate are needed to use this tool.
light.pngChecking Shape wizard using height [mm] instead of physical model option can highly reduce the runtime if the selected plate’s thickness is constant.
Created by Fredrik Lagerström on 2020/03/24 14:28
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