Product(s):	SACS
Version(s):	23
Area:	PSI

Problem

How to troubleshoot the warning of Pile Stiffness connecting joint is negative or zero in the DY-RZ Dof?

Solution

Most likely, there are few options which you can check as below:

1. Member releases and boundary conditions could result in a mechanism. Try running the analysis without the piles and see if you get any stability errors. If not, we can narrow the problem down to the psi input.
2. The load for the pile/soil may simply be too large. Try increasing the diameter of the pile or increase the capacity of your p-y curve to see if that solves the problem (You can use the p and y factors to modify the soil capacity without changing values). If that is the case, then you just need to increase the pile diameter. Recommendation to increase the pile diameter is that sometimes the load exceeds the pile capacity. If this is the case, there really isn't anything that you can do to solve the problem aside from increasing the capacity, either by increasing the diameter or increasing the soil stiffness.