missing some constraints for dummy columns

[jackmil]

hello again frank

I have some problems with Dummy column. I made a three story braced frame before and it has worked, but not worked for 9 story braced frame. I faced with this errors:

UMD2FA: matrix is singular. only 4968 pivots found.

I know the problem is in likely missing some constraints. I dont know where should I add more constraints in dummy coloum. I use roLeaningSpring in the both top and bottom end of dummy coloums with very small stiffness for avoiding singularity :

# In the base floor ( 3 bay )
fix 111 1 1 1 1 1 1
fix 112 1 1 1 1 1 1
fix 113 1 1 1 1 1 1
fix 114 1 1 1 1 1 1
fix 115 1 1 1 1 1 0; # Dummy in the base
#-----------------------------------------------------------------------------------
fix 121 0 0 1 0 1 0;
fix 122 0 0 1 0 1 0;
fix 123 0 0 1 0 1 0;
fix 124 0 0 1 0 1 0;
fix 125 0 0 1 1 1 0; # Dummy in 1 to 9 floors
#-------------------------------------------------------------------------------------
equalDOF 121 122 1; equalDOF 121 123 1; equalDOF 121 124 1; equalDOF 121 125 1;

set matDummy632291;
uniaxialMaterial Elastic $matDummy 1.e-5;
#--------------------------------------------------
proc rotLeaningCol { eleIDdummy nodeRr nodeCc matDummy } {
element zeroLength $eleIDdummy $nodeRr $nodeCc -mat $matDummy -dir 6;
equalDOF $nodeRr $nodeCc 1 2 3 4 5;
}
#---------------------------------------------------------------------------------------------------

Is there a 3D example about this?