Raft Interaction

The Raft interaction module defines the interface between the nodes on raft and the soil. Each raft interaction node in the structure is assumed to interact with a rectangular area of soil.

Definition

Node List

A list of nodes that interact with soil.

Interaction Area

A rectangular area can be defined for the interaction nodes by x and y dimensions in global axis if "Automatic" option is not used. If 'Automatic' is selected, the interaction areas will be calculated by GSA automatically. If an interaction node is connected to one 1D element or parallel 1D elements, the interaction area cannot be generated. If an interaction node is connected to the middle nodes of quadratic 2D elements, the interaction area also cannot be generated, in these two cases, the interaction area has to be defined explicitly by the x and y dimension.

Interaction Elevation

This defines the elevation of the raft nodes that interact with soil, the elevation is relative to vertical level used in soil profile definition. If 'Automatic' is selected, the z coordinate of the interaction nodes will be used as the interaction elevation.

Minimum & Maximum Pressure

The minimum pressure that can be exerted on the soil, with a positive value being compression.

If a negative minimum pressure is specified then this is the maximum tensile pressure the soil can sustain.

The maximum pressure that can be exerted on the soil. If the soil pressure is higher than the maximum pressure during raft analysis, the soil pressure will be constant and and equal to this maximum pressure.