SDOF bridge pier model in STKO

[Shayan Dadashi]

Hi,
Hope you are doing well.
I have a question about my STKO.
I am receiving the following errors when running the program but I don't know what is causing them.

(WARNING BandGenLinLapackSolver::solve() -factorization failed, matrix singular U(i,i) = 0, i= 0
WARNING BandGenLinLapackSolver::solve() -factorization failed, matrix singular U(i,i) = 0, i= 0
WARNING BandGenLinLapackSolver::solve() -factorization failed, matrix singular U(i,i) = 0, i= 0
WARNING BandGenLinLapackSolver::solve() -factorization failed, matrix singular U(i,i) = 0, i= 0
WARNING BandGenLinLapackSolver::solve() -factorization failed, matrix singular U(i,i) = 0, i= 0
WARNING: CTestNormDispIncr::test() - failed to converge
after: 1 iterations current Norm: inf (max: 0.01, Norm deltaR: nan)
WARNING: CTestNormDispIncr::test() - failed to converge
after: 34 iterations current Norm: inf (max: 0.01, Norm deltaR: nan)
NewtonLineSearch::solveCurrentStep() -the ConvergenceTest object failed in test()
StaticAnalysis::analyze() - the Algorithm failed at step: 0 with domain at load factor 2e-06
OpenSees > analyze failed, returned: -3 error flag
ERROR: the analysis did not converge
while executing
"error "ERROR: the analysis did not converge"")

I would like the STKO model to be like the tcl file attached in the rar file below. In the tcl file I do not receive such errors. Would you please help me with this?

Thank you,

[kesavapraba]

Hi, It should work in both cases correctly. However, the error says there is some connection issue (leading to singularity matrix) between node or elements. I tried to assign elastic element (with large E and G values) instead of rigid links (Rigidlink_R and Rigidlink_L) in your model, the model ran without errors.

[Shayan Dadashi]

Would you send the file you said worked without errors? because I tried that but again I am receiving some errors.

[kesavapraba]

Sure, As you'll see in the attached file, the 'rigidLink' option is creating an issue when the tendon and beam nodes coincide. I've made a temporary fix by adjusting the tendon's position. I'll be working on a more clean solution and will keep you updated.

[Shayan Dadashi]

Thank you so much.
How about the middle rigid link. Because there has to be a rigid link in the designated location. I saw your model but there was no rigid link in the middle.
In the OpenSees (TCL language) I used the same coordinates for the nodes creating the middle one but there was no issue.

[kesavapraba]

Yes, I did not add the middle link at there was already fixity at the bottom and Uz zerolength element. Just remember, rigidLink-beam doesn't make sense if the two nodes are coinciding, you can use equalDOF if that is the case.