Answer:
In the current versions of RFEM and RSTAB, it is possible to design elastic foundations for failure under tension or at compression.
In RFEM, this function can be applied to both line supports and surface supports. The definition is done under "Insert" → "Model Data" → "Line Support" / "Surface Support", or "Edit" → "Model Data" → "Line Support" /"Surface Support". Under the "Nonlinearity" option, you can set the type of failure; see Image 01.
In RSTAB, this option is only available for member elastic foundations. The definition of the failure criteria is similar; see Image 02.
