Convergence problem in shearwall modelling

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Srineshkumar
Posts: 1
Joined: Thu Nov 17, 2022 1:57 am

Convergence problem in shearwall modelling

Post by Srineshkumar » Thu May 18, 2023 5:18 am

hello everyone,
I am modelling a 2D soft storey RC building having shear wall in the ground storey. The RC frame is of 5 storey and 4 bays with height of each storey as 3m and width of each bay as 6m.Shear wall in my model is a partial one of 1m length on each side of column(not in the entire bay) and of the thickness 200mm.

I have used "dispBeamColumnInt" element for shearwall modelling and my column with Shear wall section is

#shear wall section #units-meters
section FiberInt 5 -NStrip 4 0.2 3 0.4 4 0.2 {
#vertical fibers
fiber -1.15 0 0.05 2; fiber -1.15 0.82 0.0001131 1003;fiber -1.15 -0.82 0.0001131 1003;
fiber -0.85 0 0.05 2; fiber -0.85 0.82 0.0001131 1003;fiber -0.85 -0.82 0.0001131 1003;
fiber -0.55 0 0.05 2; fiber -0.55 0.82 0.0001131 1003;fiber -0.55 -0.82 0.0001131 1003;
fiber -0.25 0 0.05 2; fiber -0.25 0.82 0.0001131 1003;fiber -0.25 -0.82 0.0001131 1003;


fiber -0.14 0 0.0533 2; fiber -0.14 0.14 0.000491 1003;fiber -0.14 -0.14 0.000491 1003;fiber -0.14 0 0.000491 1003;
fiber 0 0 0.0533 2; fiber 0 0.14 0.000491 1003;fiber 0 -0.14 0.000491 1003;
fiber 0.14 0 0.0533 2; fiber 0.14 0.14 0.000491 1003;fiber 0.14 -0.14 0.000491 1003;fiber 0.14 0 0.000491 1003;

fiber 0.25 0 0.05 2; fiber 0.25 0.82 0.0001131 1003;fiber 0.25 -0.82 0.0001131 1003;
fiber 0.55 0 0.05 2; fiber 0.55 0.82 0.0001131 1003;fiber 0.55 -0.82 0.0001131 1003;
fiber 0.85 0 0.05 2; fiber 0.85 0.82 0.0001131 1003;fiber 0.85 -0.82 0.0001131 1003;
fiber 1.15 0 0.05 2; fiber 1.15 0.82 0.0001131 1003;fiber 1.15 -0.82 0.0001131 1003;

#horiz. reinf.
Hfiber 0 0 0.000226 1003;
}

While I am doing gravity analysis and pushover analysis for frame without shearwall, my model is working fine and I am able to record the results,
but while I am trying to incorporate shearwall in the ground storey, I am getting the below error,

periods are 0.15133586600229734 0.05166039813658025 0.03618919668794684 0.03396772721757259 0.025188340543530172
WARNING: analysis .. TransientAnalysis already exists => wipeAnalysis not invoked, problems may arise
WARNING BandGenLinLapackSolver::solve() -factorization failed, matrix singular U(i,i) = 0, i= 1
WARNING NewtonRaphson::solveCurrentStep() -the LinearSysOfEqn failed in solve()
StaticAnalysis::analyze() - the Algorithm failed at iteration: 0 with domain at load factor 0.1
OpenSees > analyze failed, returned: -3 error flag
Model Built

I have tried changing the tolerance value, algorithm type, increasing the integration points and also adding more nodes over the length of shearwall but the same error is repeating.

Can anyone suggest what could be the issue and how to solve this error?

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