• Operation Mode - Select the operation mode from Solution and Data Check.
• Last Layer Number in Near Field Zone - Type the last layer number. This parameter is the maximum number of layers in the ground that the structure (including the irregular soil zone) is embedded into. The smaller this number, the less information is saved in File3, therefore less computation and disk memory will be needed to form the flexibility matrix in the ACS SASSI ANALYS module. However, this number must be large enough to ensure that the excavated soil region will not extend deeper than the specified layer number. For surface structures without assumed irregular soil zone, set this value to 0 or leave the edit box blank.
• Radius of Central Zone - Type the radius of the central zone in the point load solution. The value must be positive and non-zero. The value of this parameter depends on the geometry of the foundation discretization by finite element method. For two relatively uniform meshes this value is given in the following figure:

Figure.2. Definition of the radius for 3D meshes

An average value can be obtained for uniform meshes (uniform meshes as much as possible are recommended). For 2D cases, the radius of the central zone shall be selected as follows:

Figure .3. Definition of the radius for 2D meshes

For 2D cases the results are not sensitive to changes in the assumed radius for the central zone as long as this radius is of the same order as the dimension of the finite elements in the interaction volume.