Soil-Structure System

[tamhidia]

Hi
Dear all
I wrote a code for getting responses of a Soil-Structure system.I used Tabas strong ground motion record in X direction to analyze my system.But I got response from node 2 (Foundation) in Y direction. I don't know why it happens. Can anyone help me?
Regards
My code is :


wipe
model basic -ndm 2 -ndf 3
node 1 0. 0.
node 2 0. 0.
node 3 0. 0.
node 4 0. 0.
node 5 0. $h
fix 3 1 1 1
fix 1 0 1 1
equalDOF 2 4 1 2
equalDOF 2 1 1
mass 2 $mf 1.e-25 $If
mass 5 $ms 1.e-20 0.
uniaxialMaterial Elastic 1 $kh
uniaxialMaterial Elastic 2 $kr
uniaxialMaterial ElasticPP 3 [expr $ke*pow($h,2)] $epr
uniaxialMaterial Viscous 4 $ch 1.0
uniaxialMaterial Viscous 5 $cr 1.0
element zeroLength 1 2 3 -mat 1 -dir 1 -doRayleigh 1
element zeroLength 2 1 2 -mat 2 -dir 6 -doRayleigh 1
element zeroLength 3 2 4 -mat 3 -dir 6 -doRayleigh 1
element zeroLength 4 2 3 -mat 4 -dir 1
element zeroLength 5 1 2 -mat 5 -dir 6
geomTransf Linear 1
element elasticBeamColumn 6 4 5 1.e6 2.e11 1.e6 1
equalDOF 4 5 3
set xDamp $kesai
set nEigenI 1
set nEigenJ 2
set lambdaN [eigen $nEigenJ]
set lambdaI [lindex $lambdaN [expr $nEigenI-1]]
set lambdaJ [lindex $lambdaN [expr $nEigenJ-1]]
set omegaI [expr pow($lambdaI,0.5)]
set omegaJ [expr pow($lambdaJ,0.5)]
set alphaM [expr $xDamp*(2*$omegaI*$omegaJ)/($omegaI+$omegaJ)]
set betaKcomm [expr 2.*$xDamp/($omegaI+$omegaJ)]
rayleigh $alphaM 0.0 $betaKcomm 0.0
set accel "Series -dt 0.001 -filePath tabasdt0.001.txt -factor 9.81"
pattern UniformExcitation 3 1 -accel $accel
set dt 0.001
constraints Transformation
numberer RCM
system BandGeneral
test EnergyIncr 1.0e-6 20
algorithm Newton
integrator Newmark 0.5 0.25
analysis Transient
analyze [expr int(32.82/$dt)] $dt