Pad base, strip base and pile cap design forces

Tekla Structural Designer
Tekla Structural Designer

Pad base, strip base and pile cap design forces

Forces acting on supports

The following forces and moments on the supports are determined from the analysis of the active load combinations:

  • Vertical force in direction Z
  • Horizontal forces in directions Y and X
  • Moments around X and Y axis

A torsional moment around the Z axis is also determined, but the base/pile cap is not designed for this in the current release.

Foundation self weight

The foundation self-weight is automatically calculated and applied as an added load, Fswt

Soil self weight

The surcharge depth and soil unit weight that have been specified in the base/pile cap properties are used to determine the soil self weight. This is applied as an added load, Fsoil


In the current release, horizontal pressure caused by soil is not considered.

Additional surcharge loads

For isolated foundations user can apply additional surcharge loads: acting in the global Z direction.

  • Permanent (dead) surcharge load
  • Variable (live) surcharge load

Design Forces

To obtain the design forces, the loads due to foundation self weight, soil self weight and additional surcharge are added to the forces acting on the supports.

These design forces (axial load and bi-axial shear and moment) are then applied to the base/pile cap at the foundation level.


In the current release lateral stability of piled foundation systems is not considered in software design checks.

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