Modify Soilin stiffness parameters for seismic analysis

Definition, application

This feature is available only for PPE default.

Visible only if surface support type Soil-in and seismic LC is available in project.

These coefficients are applied on soil-in parameters only for modal analysis before calculation of seismic LCs.

How to choose right coefficient value? Theoretical background

1) in every seismic spectrum it is necessary to define "Subsoil type" according code.

2) In Code (for example in Eurocode 8) there is definition of one special parameter for every subsoil type - "Shear wave velocity".

3) Dependency between this parameter and G parameter of soil is:

4) It is necessary to take into account all layers of soil until 30 m, and there are more important layers closer to structure than others. So it is possible to calculate some average parameters of soil E, G and compare them with parameters calculated by shear wave velocity. Ratio between them is coefficient which can be used solver setup for calculation.

5) As a basic info you can look at the table below, where some values for basic types of soils are calculated: