Using Links to Model Beams on Elastic Foundation

SAP2000 enables you to model compression-only (gap) links for the vertical direction as follows (in V12):

(1) Define the link properties via "Define > Section Properties > Link/Support Properties" menu command. Set "Link/Support Type" to Gap and specify link properties in the Directional Properties section of the form. You can specify compression-only properties independently for each direction. Select "Nonlinear", click Modify/Show to set stiffness and open distance:

(2) Select a joint to which you need to assign the link and used "Draw > Draw 1 Joint Link" menu command to place the link in the model.

Please note that the program has both springs and links. The links are a more powerful feature as they enable to model various types of nonlinear behavior and can be used not only as supports, but also as 2-joint links to connect two separate joints in the model. Please remember that you will need to run Nonlinear analysis to activate the nonlinear properties of gap links.