shellmitc4 element

[majidkhan]

hi
I modeled nonlinear 5 story shear wall building with shellmitc4 element and run pushover analysis. I have 3 questions

first results on sap and opensees isn't same and have 18 percent difference. discretization of mesh on sap is fine . is this difference usual?
my second question is about nonlinear part and concepts . how can I control this part? I change epsilons ft and fy(rebar) but my model have elastic or low inelastic behavior
third how can calculate shear retention factor (stc) and out of plane shear modules

# fc ft fcu epsc0 epscu epstu stc
nDMaterial PlaneStressUserMaterial 1 40 7 $fc [expr 0.117*$fc] [expr -0.2*$fc] -0.002219 -0.006 0.001439 0.08

# nDMaterial PlateFromPlaneStress $matTag $PlaneStressMatTag $OutOfPlaneShearModulus
nDMaterial PlateFromPlaneStress 4 1 1.042e10

uniaxialMaterial Steel02 7 3.8e8 1.99e11 0.01 18.5 0.925 0.15
nDMaterial PlateRebar 8 7 90

section LayeredShell 1 11 4 0.015 4 0.015 8 0.000392 4 0.02 4 0.02 4 0.02 4 0.02 4 0.02 8 0.000392 4 0.015 4 0.015

thanks

[fmk]

how do the results compare with just elastic material?

[fmk]

and you have steel in only vert dirn.. is wall tall?

[majidkhan]

Dear frank thanks for your answer
In my model Elastic slope on sap pushover curve and opensees have 18 percent difference with this material. Is model incorrect?
I check geometric of model and matlab code.

Which part of code i must change to see inelastic behavior?
And yes i model only vertical rebars for check results with sap. I Add horizontal steel. i forgot this part.
And whats your opinion about shear retention factor and out of plane modules

Thanks a lot

[fmk]

until the elastic and sap give the same answer there is no point at looking at the inelastic case.

there is an exampe in the verification suite that checks some elastic walls versus SAP and ETABS. I suggest you have a look "PlanarShearWall.tcl"

http://opensees.berkeley.edu/WebSVN/lis ... ication%2F

[kaivo]

if you keep doing so, the results good?