BNWF- soil elastic stiffness qz material ?

r-m · Post by **r-m** » Sat Nov 29, 2008 12:33 pm

hi to all

i want to model uplift in foundation with superstructre and foundation structure and soil model.

i did pushover analysis and i have used esaltoplastic fema356 soil model ,in another software.

now i want to do time history analysis with opensees .
i have built the model 1story , 1 bay , with CBF brace and shallow foundation structure( with elastic beam column) and soil model with qz material.(BNWF)

i have a problem about period in opensees with soil model(sand -qz material). (whitout foundation structure and soil model , i dont have any problem about period in fixed model .) in another software that i did pushover analysis period was 0.23 s but in opensees model is about 0.14 s

i calculate qult with meyerhof formula and k=fema 356 soil stiffness(chapter4) for calculate z0=1.39*qult/k.

1-i know that there is a diffrence beetwin k elastic from fema356 and k elastic that was calculated in qz simple for sand , but i dont know where is the problem?

2-maybe my foundation structure model is wrong. but i dont know.

3- i didnt consider foundation sliding so i fixed the ends of columns in dx and tetez dof and release them in dy dof. is it true?

Please help meeeeee . i am confused!!!!!!!!!!!!!!!!!!!!!!! specially when i have modeled foundation structure and soil model with peer504 and peer 704 reports.

thanks alot

my file:

wipe

########## building model:

model basic -ndm 2 -ndf 3

####################nodal coordinates

# superstructure node

node 1 0 0 0
node 2 0 0 0
node 3 400 0 0
node 4 400 0 0
node 5 0 300 0
node 6 1 300 0
node 7 400 300 0
node 8 399 300 0
node 9 4 3 0
node 10 396 3 0
node 11 396 297 0
node 12 4 297 0
node 13 200.12 150.16 0
node 14 199.88 150.16 0
node 15 4 3 0
node 16 396 3 0
node 17 396 297 0
node 18 4 297 0
node 19 1 300 0
node 20 399 300 0

# fondation node

node 21 -40 0 0
node 22 -40 0 0
node 24 0 0 0
node 25 40 0 0
node 26 40 0 0
node 27 80 0 0
node 28 80 0 0
node 29 120 0 0
node 30 120 0 0
node 31 160 0 0
node 32 160 0 0
node 33 200 0 0
node 34 200 0 0
node 35 240 0 0
node 36 240 0 0
node 37 280 0 0
node 38 280 0 0
node 39 320 0 0
node 40 320 0 0
node 41 360 0 0
node 42 360 0 0
node 44 400 0 0
node 45 440 0 0
node 46 440 0 0

############################# mass

mass 5 18.1 18.1 0.001
mass 7 18.1 18.1 0.001
mass 21 0.156 0.156 0
mass 1 0.156 0.156 0
mass 25 0.156 0.156 0
mass 27 0.156 0.156 0
mass 29 0.156 0.156 0
mass 31 0.156 0.156 0
mass 33 0.156 0.156 0
mass 35 0.156 0.156 0
mass 37 0.156 0.156 0
mass 39 0.156 0.156 0
mass 41 0.156 0.156 0
mass 3 0.156 0.156 0
mass 45 0.156 0.156 0

###################### bondary conditions

fix 21 0 0 0
fix 1 1 0 1
fix 25 0 0 0
fix 27 0 0 0
fix 29 0 0 0
fix 31 0 0 0
fix 33 0 0 0
fix 35 0 0 0
fix 37 0 0 0
fix 39 0 0 0
fix 41 0 0 0
fix 3 1 0 1
fix 45 0 0 0
fix 22 1 1 1
fix 24 1 1 1
fix 26 1 1 1
fix 28 1 1 1
fix 30 1 1 1
fix 32 1 1 1
fix 34 1 1 1
fix 36 1 1 1
fix 38 1 1 1
fix 40 1 1 1
fix 42 1 1 1
fix 44 1 1 1
fix 46 1 1 1

equalDOF 5 7 1
equalDOF 5 19 1
equalDOF 5 20 1

##################################### materilas

uniaxialMaterial Steel01 1 2400 2100000 0.03
uniaxialMaterial Elastic 2 0.001
uniaxialMaterial QzSimple1 3 2 30767 3.2 0.001 0.1
#qult=30767(kg) , k fema356=13425(kg/cm)

############################ sections

#Beam section ipe 27
source Wsection.tcl

set secID 1
set matID 1
set d 27; # depth
set bf 13.5 ; # flange width
set tf 1.02 ; # flange thickness
set tw 0.66 ; # web thickness
set nfdw 4; # number of fibers along dw
set nftw 2; # number of fibers along tw
set nfbf 4; # number of fibers along bf
set nftf 2; # number of fibers along tf
Wsection $secID $matID $d $bf $tf $tw $nfdw $nftw $nfbf $nftf

#column section box14x1
source boxsection.tcl

set secID 2
set matID 1
set d 14
set t 1
set nfdk 2
set nfdb 4
boxsection $secID $matID $d $t $nfdk $nfdb

#brace section box10x1
source boxsection.tcl

set secID 3
set matID 1
set d 5
set t 1
set nfdk 2
set nfdb 4
boxsection $secID $matID $d $t $nfdk $nfdb

#brace section box5x1
source boxsection.tcl

set secID 4
set matID 1
set d 5
set t 1
set nfdk 2
set nfdb 4
boxsection $secID $matID $d $t $nfdk $nfdb

############################# coordinat transformation

geomTransf PDelta 1
geomTransf Corotational 2
geomTransf Linear 3

######################## elements

########################## elements superstruture

element nonlinearBeamColumn 1 2 5 3 2 1 ; # column#
element nonlinearBeamColumn 2 5 19 3 1 3 ; # beam
element nonlinearBeamColumn 3 6 8 3 1 3 ; # beam
element nonlinearBeamColumn 4 7 20 3 1 3 ; # beam
element nonlinearBeamColumn 5 4 7 3 2 1 ; # column
element nonlinearBeamColumn 6 10 13 8 3 2 ; # brace
element nonlinearBeamColumn 7 13 12 8 3 2 ; # brace
element nonlinearBeamColumn 8 9 14 8 3 2 ; # brace
element nonlinearBeamColumn 9 14 11 8 3 2 ; # brace
element nonlinearBeamColumn 10 1 15 8 3 2 ; # brace
element nonlinearBeamColumn 11 3 16 8 3 2 ; # brace
element nonlinearBeamColumn 12 7 17 8 3 2 ; # brace
element nonlinearBeamColumn 13 5 18 8 3 2 ; # brace

source rotSpring2D.tcl

# eleID nA nB matID

rotSpring2D 14 19 6 2

rotSpring2D 15 20 8 2

rotSpring2D 16 1 2 2

rotSpring2D 17 3 4 2

rotSpring2D 18 15 9 2

rotSpring2D 19 16 10 2

rotSpring2D 20 18 12 2

rotSpring2D 21 17 11 2

################### element foundation structure Hf=Bf=40cm

# eletag i j A E Iz Transftag

element elasticBeamColumn 22 21 1 1600 250998 213333 3
element elasticBeamColumn 23 1 25 1600 250998 213333 3
element elasticBeamColumn 24 25 27 1600 250998 213333 3
element elasticBeamColumn 25 27 29 1600 250998 213333 3
element elasticBeamColumn 26 29 31 1600 250998 213333 3
element elasticBeamColumn 27 31 33 1600 250998 213333 3
element elasticBeamColumn 28 33 35 1600 250998 213333 3
element elasticBeamColumn 29 35 37 1600 250998 213333 3
element elasticBeamColumn 30 37 39 1600 250998 213333 3
element elasticBeamColumn 31 39 41 1600 250998 213333 3
element elasticBeamColumn 32 41 3 1600 250998 213333 3
element elasticBeamColumn 33 3 45 1600 250998 213333 3

############################ element soil model

element zeroLength 34 22 21 -mat 3 -dir 2
element zeroLength 35 24 1 -mat 3 -dir 2
element zeroLength 36 26 25 -mat 3 -dir 2
element zeroLength 37 28 27 -mat 3 -dir 2
element zeroLength 38 30 29 -mat 3 -dir 2
element zeroLength 39 32 31 -mat 3 -dir 2
element zeroLength 40 34 33 -mat 3 -dir 2
element zeroLength 41 36 35 -mat 3 -dir 2
element zeroLength 42 38 37 -mat 3 -dir 2
element zeroLength 43 40 39 -mat 3 -dir 2
element zeroLength 44 42 41 -mat 3 -dir 2
element zeroLength 45 44 3 -mat 3 -dir 2
element zeroLength 46 46 45 -mat 3 -dir 2

eigen 1

# recorders:

recorder Node -file deformationx5.out -time -node 5 -dof 1 disp
recorder Node -file shear.out -time -node 5 -dof 1 reaction
recorder Node -file deformationx21.out -time -node 21 -dof 2 disp
recorder Node -file deformationx45.out -time -node 45 -dof 2 disp

set pi [expr 2*asin(1)]
set lambda [eigen 1]
set omega [expr pow($lambda,0.5)]
set Tperiod [expr 2*$pi /$omega]; # period (sec)
puts "$Tperiod"

pattern Plain 1 Linear {
load 5 1 0 0
}
system BandGeneral
constraints Transformation
test NormDispIncr 1.0e-8 1000 0
algorithm Newton
numberer RCM
integrator DisplacementControl 5 1 0.01
analysis Static
analyze 200
integrator DisplacementControl 5 1 -0.02
analysis Static
analyze 200
integrator DisplacementControl 5 1 0.01
analysis Static
analyze 200

jaugalde · Post by **jaugalde** » Sat Nov 29, 2008 2:20 pm

I have no clue why your analysis in other software is different. The other software uses the same models as OpenSees? Spring spacing, stiffnesses, qult are all the same in both software?

I would recommend you start with pushover. Make sure the moment capacity and initial total footing vertical, horizontal, rotational stiffnesses are what they should be. The Appendices of the 2007 PEER report you refer to has OpenSees input files used in the benchmarking and validation for both the uncoupled BNWF spring method and the coupled springs in the soilfootingsection2D element.

Hope this helps.

r-m · Post by **r-m** » Sat Nov 29, 2008 2:47 pm

thanks

1-but is there soilfootingsection2d element in opensees?

2-opensees calculated elastic soil maybe from z0 and qult and i dont know how calculat it so i dont know our elastic soil is equal?????(i defined qult and k that use for z0 is equal in both of software)

thanks again