Soil Anchors for seismic footings - tension-only springs?

Question

1.) I am using RAM Concept to model a seismic footing under a shear wall. This wall is carrying high seismic shear and moment but has relatively low axial load, so it is tending to overturn. One option is to make the footing larger and pick up nearby columns for additional gravity load. Alternative is to use soil anchors to hold down the footing. I can use point springs in RAM Concept, but I would like to model the anchors as taking tension only. Is it possible to create tension-only springs in RAM? 
 
 2.) I am using area springs to model the soil under the footing. I am running a Zero Tension analysis, however I find that the analysis is still producing tension in some of the soil springs; physically this is not possible. Is this simply because I need to increase the number of iterations in the solver? Currently doing 8 iterations on the zero tension solver. 
 
 Thanks, 
 Andrew

Seth Guthrie · Accepted Answer

1) Point springs in Concept are always linear-elastic. You could remove a small area of the area spring (which is compression-only) to makeup the difference. 
 2) Probably yes. The program is performing an iterative approach to reach the no tension solution. In a system subject to overturning a solution may take many iterations, or may not even be possible. Besides adjusting the zero tension criteria, you might also refine (shrink) the mesh to give you more springs to work with or add some stabilizing loads.