Base and Subgrade Layer Geometry
In the Base/Subgrade sub-panel, the user specifies the number of elastic solid base/subgrade layers to be considered (0-3) via checkboxes on the left, and the thickness of each layer on the right. The upper-most layer is considered the base layer, and the second and third layers are designated Subgrade 1 and Subgrade 2 when specifying base/subgrade material properties. There is always a dense liquid foundation below the bottom-most layer, and if no elastic solid layers are specified, all slabs are supported directly on a dense liquid.