Gravity analysis doesn't converge

[amirmassoud]

Hi everybody ...
My model is a 3D reinforced concrete structure with shear walls.
It contains 20 stories.
Elements are defined as fiber sections and modeled with dispBeamColumn elements.
My goal is to run time history analysis.
But gravity analysis doesn't converge.
Help me if possible ...
# --------------------
# Gravity load analysis
# --------------------
wipeAnalysis ;
constraints Transformation ;
numberer RCM ;
system SparseGeneral ;
test EnergyIncr 1.00e-7 25 1 ;
algorithm ModifiedNewton ;
integrator LoadControl 0.01 ;
analysis Static ;
analyze 100 ;
loadConst -time 0.0 ;
# --------------------

[fmk]

if it fails atfirst step due to solver failing your model is probably missing some boundary conditions or incorrect material and element commands,if it fails because it cannot converge the loads are too great or the materials/sections are incorrectly defined.

always start with an elastic model

[amirmassoud]

Dear fmk,
The message is :
ModifiedNewton::solveCurrentStep<> -the ConvergenceTest object failed in test <>
StaticAnalysis::analyze<> -the algorithm failed at iteration 45 with domain at load factor 0.46
openSees > analyze failed , returned: -3 error flag
Is it because of great loads or incorrect materials/section?!