Tall building pushover analysis fail

[pp_0928]

Hi all

I model a 20 stories Moment Frame 3D structure in Opensees.

The details are as followed:
Column: Fiber section, use nonlinearbeamcolumn element, using steel02 materials
Beam: 1) elastic beamcolumn element; 2) zerolength element in both ends, using bilin materials
analysis command: 1) constraints Transformation; 2) numberer RCM; 3) system SparseSYM; 4) algorithm Newton


Problem: No matter how far I push, the analysis stops at around 2% drift. Even it give 100 trash data point, same force, same displacement.
The feedback in the software, common problem:
1)WARNING - ForceBeamColumn3d::update - failed to get compatible element forces & deformations for element: 1576(4.42546e+006, dW0: 736388)
2)DisplacementControl: update- model failed to update for new dU
3)WARNING NewtonRaphson::solveCurrentStep() -the Integrator failed in update()
4)Staticanlysis: analyze() - the Algorithm failed at iteration: 0 with domain at load factor

I try to make some part of the model linear:
1) Linear column, Linear beam: No problem
2) Nonlinear column, linear beam: still warning- ForceBeamColumn3d::update failed to get compatible element forces & deformations for element: 1576(4.42546e+006, dW0: 736388)
3) Linear column, nonlinear beam: fail to convergence, but the opensees convergence loop fix a lot of problem.


In the end, I change nonlinearbeamcolumn element to dispBeamColumn element, no warning - ForceBeamColumn3d:. BUT IT GIVES ME A WRONG RESULT.( I have a perform3D model to compare)

Please give me suggestions. If you like, I can send my model to you. Many thanks.

Peng

[vesna]

The problem is created by element 1576. Try fixing this element rather then the whole model. Make sure it is defined well.

If you replace force-based beam-column element with disp-based elemnts you need several disp-based element in place of one force-based element.

[pp_0928]

Many thanks for your reply, Vesna. I also send you my model.

Actually, element 1576 is column element. It works perfectly when it's 10-story-building. But when it goes to 20-story-building, there're hundreds of similar warning in different columns. I'm thinking whether it is out of the capability of opensees algorithm for calculation.

One experiment I do, two models :1)Column linear and beam nonlinear, it stops analysis around 2%IDR, no matter how far I push it; 2)Column nonlinear and beam linear, although it has "WARNING - ForceBeamColumn3d, it can finish". Can I make a conclusion my beam has problem?

I can't understand why all element, materials work perfectly in lower stories building, and it stops analysis in taller building.

Thanks

Peng








I models in this way:

proc AISCsectionsfiber { secID matID AISC_Wsection nfdw nftw nfbf nftf orient secIDA } {
# ###################################################################
# AISC_sections_fiber $secID $matID $d $bf $tf $tw $nfdw $nftw $nfbf $nftf orient secIDA
# ###################################################################
# create a standard W section given the nominal section properties
# written: Farzin Zareian & Peng Zhong
# date: 08/11
# input parameters
# secID - section ID number
# matID - material ID number
# secIDA - section ID number after using aggregator

# nfdw = number of fibers along web depth
# nftw = number of fibers along web thickness
# nfbf = number of fibers along flange width
# nftf = number of fibers along flange thickness
# orient = orientation 1 for I shape and 2 for |-| shape



# d = nominal depth
# tw = web thickness
# bf = flange width
# tf = flange thickness

```````
```````
```````
```````

} elseif {$AISC_Wsection =="W4X13"} {
set W 13;
set A 3.83;
set H 4.16;
set BF 4.06;
set TW 0.28;
set TF 0.345;
set BF_2TF 5.88;
set H_TW 10.6;
set IX 11.3;
set ZX 6.28;
set SX 5.46;
set RX 1.72;
set IY 3.86;
set ZY 2.92;
set SY 1.9;
set RY 1;
set J 0.151;
set Aweb 0.9716;

} else {
puts "section not found"
}



if {$orient == 1 } {

set dw [expr $H - 2 * $TF]
set y1 [expr -$H/2]
set y2 [expr -$dw/2]
set y3 [expr $dw/2]
set y4 [expr $H/2]

set z1 [expr -$BF/2]
set z2 [expr -$TW/2]
set z3 [expr $TW/2]
set z4 [expr $BF/2]

section fiberSec $secID {
# nfIJ nfJK yI zI yJ zJ yK zK yL zL
patch quadr $matID $nfbf $nftf $y1 $z4 $y1 $z1 $y2 $z1 $y2 $z4
patch quadr $matID $nftw $nfdw $y2 $z3 $y2 $z2 $y3 $z2 $y3 $z3
patch quadr $matID $nfbf $nftf $y3 $z4 $y3 $z1 $y4 $z1 $y4 $z4
}

set G 11154.0

set VMat [expr $secIDA+1000]

uniaxialMaterial Elastic $VMat [expr $A*$G] ;

set TMat [expr $secIDA+1100]

uniaxialMaterial Elastic $TMat [expr $J*$G] ;


#column section Aggregator (with shear and torsion)

section Aggregator $secIDA $VMat Vz $VMat Vy $TMat T -section $secID ;




} elseif {$orient == 2 } {


set dw [expr $H - 2 * $TF]
set y1 [expr -$H/2]
set y2 [expr -$dw/2]
set y3 [expr $dw/2]
set y4 [expr $H/2]

set z1 [expr -$BF/2]
set z2 [expr -$TW/2]
set z3 [expr $TW/2]
set z4 [expr $BF/2]

section fiberSec $secID {
# nfIJ nfJK yI zI yJ zJ yK zK yL zL
patch quadr $matID $nftf $nfbf $z1 $y2 $z1 $y1 $z4 $y1 $z4 $y2
patch quadr $matID $nfdw $nftw $z2 $y3 $z2 $y2 $z3 $y2 $z3 $y3
patch quadr $matID $nftf $nfbf $z1 $y4 $z1 $y3 $z4 $y3 $z4 $y4
}

set G 11154.0

set VMat [expr $secIDA+1000]

uniaxialMaterial Elastic $VMat [expr $A*$G] ;

set TMat [expr $secIDA+1100]

uniaxialMaterial Elastic $TMat [expr $J*$G] ;


#column section Aggregator (with shear and torsion)

section Aggregator $secIDA $VMat Vz $VMat Vy $TMat T -section $secID ;

} else {
puts "Your Orientation Number is Off"
}
}

AISCsectionsfiber $c18_fs $SteelMat W24X146 $nfdw $nftw $nfbf $nftf 2 $c18_fsA;

element nonlinearBeamColumn 1576 1937 335 $numIntgrPts $c18_fsA $IDColTransf_h1 ; # C18_W24X146fs