STAAD.Pro Help

M. To assign a foundation support

To automatically model a support using foundation parameters, use the following procedure.

Isolated footing dimensions and subgrade modulus values are specified in the current input units. You may want to change those to a convenient value before specifying a foundation support.

STAAD.Pro can take foundation parameters for footings or mat foundations and automatically model spring supports.

  1. Select the nodes that will have the same support condition.
  2. On the Specification ribbon tab, select the Foundation tool in the Supports group.

    The Create Support dialog opens to the Foundation tab.
  3. Select the Foundation type to model:

    Footing - a rectangular, isolated footing (i.e., spread footing) area is used to model spring stiffness using the subgrade modulus

    or

    Elastic Mat - the program calculates the influence area of the load and then calculates a spring stiffness based on this area using the subgrade modulus

    or

    Plate Mat - the program calculates the influence area of the load within a specified plate and then calculates a spring stiffness based on this area using the subgrade modulus

    For additional details on the foundation types and their applicability, refer to TR.27.3 Automatic Spring Support Generator for Foundations.
  4. Select the Direction of the resistance of the spring supports.

    The directions X, Y, or Z generate a spring in that global direction. The other two global directions are fixed against translation and moment about the selected direction is also fixed. The directions X Only, Y Only, or Z Only generate a spring in that global direction only.

  5. Type the Subgrade Modulus of the soil.
  6. (Optional) For Elastic Mat or Plate Mat foundation types, check the option Print influence area of each joint to include this information in the output.
  7. (Optional) For Elastic Mat or Plate Mat foundation types, select a nonlinear spring option if necessary:
    Option Description
    None linear springs are generated
    Compression Only generated springs are compression only (made inactive if in tension)
    Multi-Linear generated springs can have a multilinear displacement-spring constant curve associated with the mat foundation
    Tip: Multilinear springs must be specified using the STAAD Editor. The dialog box cannot accept displacement-spring constant curve data.
  8. Either:
    To… Do the following…
    add the support type to the model and assign to the current node selection click Assign.
    add the support to the model for later assignment click Add.
    The dialog closes.
Parent topic: M. Supports
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