Menu

Foundation pad design

senfd.01

Highlights

Both the stability check and the AutoDesign of pad foundations have an optimal performance speed
You are able to check both the superstructure as the foundations
Optimization tool: the AutoDesign of pad foundations can be carried out in a fast way. You can optimize one or more dimensions of the pad foundation. With the sensitivity optimization, several parameters can be optimized together. SCIA Engineer will find a pad foundation with optimal geometry dimensions
The AutoDesign of pad foundations can be performed together with the AutoDesign of the structure itself
A detailed output with input data, results and used articles is available.
A unity check can be performed: this gives the most critical value of the three checks.

 

Pad foundations are used to support single columns, spreading the load to the ground below. They are generally square or rectangular in plan, with the plan area being determined by the permissible bearing strength of the soil. The shape in plan is enforced by the arrangement of the columns and the load to be transferred to the soil. This functionality in SCIA Engineer enables you to perform a stability check of pad foundations in accordance with EC-EN 1997-1.

Foundation pad design The support type Pad foundation (previously called ‘Foundation block’) extends a wide set of support types in SCIA Engineer. Besides the stiffness, which is taken into account under the structure, it is also possible to check the stability of the pad foundation according to EN 1997-1: Geotechnical design-Part 1: General rules, 2004.

Three separate checks can be executed:

  •   Bearing resistance check;
  •   Sliding resistance check;
  •   Eccentricity check.

Foundation pad design Furthermore, the AutoDesign tool optimizes the dimensions of the pad foundation. It is possible to input the maximum stress received from a geotechnical report and use this value for the automatic design. The pad foundation properties are defined by:

  • Pad foundation geometry;
  • Subsoil properties.

Design and optimization tools are available for single or multiple selected pad foundations as well as in the Overall AutoDesign for optimization of all pad foundations in the model.

Foundation pad design Foundation pad design Foundation pad design

Geotechnical combinations

Set B and set C of the EN-ULS (STR/GEO) combination defined in EN 1990 are available for the foundation check.

For the check a result class GEO is automatically created. This class contains all combinations of types: EN-ULS (STR/GEO) Set B and EN-ULS (STR/GEO) Set C. The latter is specifically used for geotechnical design according to design approach 1.

Pad foundation input

Geometry and other properties of pad foundations are input in a Pad foundation dialogue. Moreover, the subsoil library is linked to the pad foundation properties.

Pad foundation stability check

In general, three separate checks are executed:

  • A Bearing resistance check is executed according to art.6.5.2 and Annex D of EN 1997-1. The vertical design loading Vd should be equal or smaller than the bearing resistance Rd.
  • A Sliding resistance check is executed according to art. 6.5.3 of EN 1997-1. The horizontal design loading Hd should be equal or smaller than the sum of the sliding resistance Rd and the positive effect of the earth pressure at the side of the foundation Rp,d.
  • An Eccentricity check is executed according to art.6.5.4 of EN 1997-1: special precautions are required for loads with large eccentricities.

When executing the check, the safety and resistance factors which are applied depend on one of the 3 design approaches chosen in the geotechnics setup.

Foundation pad design Foundation pad design Foundation pad design

AutoDesign

An optimization tool for pad foundations is also available. This enables you to search easily for an optimal geometry of the foundation block. The user can choose any of the pad foundation dimensions or even optimize several parameters in one step. This is called sensitivity optimization: it verifies the sensitivity of different parameters to the check.

The maximum check limit is configurable for each of the three main checks.

Category: 
Included in Edition: 
Concept
Professional
Expert
Ultimate