Determination of Design Values

The Pad Foundation check is executed for a Result Class.

Depending on the Design Approach set in the National Annex Setup, the sets of safety factors are read from the setup as follows:

• For Design Approach 1 the safety sets depend on the combination type.
  For combinations of type EN-ULS (STR/GEO) Set B sets M1 & R1 are used.
  For combinations of type EN-ULS (STR/GEO) Set C sets M2 & R1 are used.
  For any other combination sets M1 & R1 are used.
• For Design Approach 2, in all cases sets M1 & R2 are used.
• For Design Approach 3, in all cases sets M2 & R3 are used.

For detailed information regarding the different combination types, reference is made to EN 1990 [Ref.4]

In case the functionality ‘Subsoil’ is activated in the Project Data a new class ‘GEO’ is generated automatically for use in the Pad Foundation check.

This class contains all combinations of the following types:
- EN-ULS (STR/GEO) Set B
- EN-ULS (STR/GEO) Set C

A Result Class may also contain load cases or non-linear combinations. These are seen as ‘Any combination’ for the check.

For Design Approach 1 the class for which the check is executed needs to contain at least one combination of each of the following types:
- EN-ULS (STR/GEO) Set B
- EN-ULS (STR/GEO) Set C

In case the class for which the user wishes to execute the check does not comply with this requirement, the check is not executed and a warning is shown instead.

For Design Approaches 2 & 3 there is no requirement for the content of the class.

It is advised to use the "Brute force (slow)" combinator strategy when executing the pad foundation check as it goes through almost all combination keys (duplicates are filtered out even if they belong to different combination types such as set B and set C).
This method is slower than the default setting "Extreme forces" which filters out combination keys that have no extreme forces (min/max) in it.

Using the above information, the design values for the soil properties are determined:

Design value	Formula
	with: read from Subsoil Library read from National Annex Setup
	with: read from Subsoil Library read from National Annex Setup
	with: read from Subsoil Library read from National Annex Setup
	with: specific weight read from Library read from National Annex Setup
	with: weight read from Pad foundation input Data read from National Annex Setup

A final safety factor which needs to be determined concerns the safety factor for the weight of the pad foundation and the backfill material. This safety factor is taken as the safety factor for the first permanent load case for the combination under consideration i.e. γ_G.

In case a combination does not have a permanent load case, γG is taken as 1,00.

Projects containing the pad foundation check in the old document can give bad output formatting as the old document is no longer maintained. It is advised to do the project reporting within the Engineering Report.