Difference in ModeShape between Sap & Opensees

[MRG]

dear all
i have simple twobay onestory frame which i model in sap & opensees , i get period with difference about 7% but i get Modeshapes with much difference , i use modeshapes for modal pushover analysis therefore it should be acuurate moreover i often get much difference between periods from Sap and Opensees (5-20%) that i guess it is for diffrence between ModeShapes but in small cases for example onestory diffrence is insignificant, Please help me !
Thanks for your time and best regards.

for aforementioned frame :

Comparision Between Periods
Sap : T1=0.626219s , T2=0.357047s , T3=0.284585s ;
Opensees : T1=0.579707s , T2=0.325239s , T3=0.286107s ;

Comparision ModeShapes
Sap node 2 4 6
1thMode 1 1.129101284 2.960770328
2thMode 1 0.989233954 -1.092339545
3thMode 1 0.74122807 3.665935673

Opensees node 2 4 6
1thMode 1 1.212474448 4.487161589
2thMode 1 1.03240444 -0.781190404
3thMode 1 0.9043333 0.953365185

wipe
file mkdir Data
model basic -ndm 2 -ndf 3
# Coordinates
node 1 -9 0
node 2 -9 3
node 3 0 0
node 4 0 3
node 5 9 0
node 6 9 3

# fix supports
fix 1 1 1 1
fix 3 1 1 1
fix 5 1 1 0

# Assign Masses
mass 1 0 0 0
mass 2 41298.51 41298.51 0
mass 3 0 0 0
mass 4 82597.01 82597.01 0
mass 5 0 0 0
mass 6 41298.51 41298.51 0

# Define Materials
set Steel 1001
set E_Steel 20000000000
set Fy_Steel 24000000
set H_Ratio_Steel 0.02
uniaxialMaterial Steel01 $Steel $Fy_Steel $E_Steel $H_Ratio_Steel

# Define Frame Sections
proc Wsection { secID matID d bf tf tw nfdw nftw nfbf nftf} {
set dw [expr $d-2*$tf]
set y1 [expr -$d/2.]
set y2 [expr -$dw/2.]
set y3 [expr $dw/2.]
set y4 [expr $d/2.]
set z1 [expr -$bf/2.]
set z2 [expr -$tw/2.]
set z3 [expr $tw/2.]
set z4 [expr $bf/2.]
section fiberSec $secID {
patch quad $matID $nftf $nfbf $y3 $z1 $y4 $z1 $y4 $z4 $y3 $z4
patch quad $matID $nfdw $nftw $y2 $z2 $y3 $z2 $y3 $z3 $y2 $z3
patch quad $matID $nftf $nfbf $y1 $z1 $y2 $z1 $y2 $z4 $y1 $z4
}
}
Wsection 1 $Steel 0.1273 0.127 0.009144 0.006096 15 6 8 6
Wsection 2 $Steel 0.9703 0.3 0.0211 0.016 30 10 30 10

# Define Elements ; two Columns and one Beam
set numIntgrPts 10
geomTransf Linear 1
element nonlinearBeamColumn 1 1 2 $numIntgrPts 2 1
geomTransf Linear 2
element nonlinearBeamColumn 2 3 4 $numIntgrPts 2 2
geomTransf Linear 3
element nonlinearBeamColumn 3 5 6 $numIntgrPts 1 3
geomTransf Linear 4
element nonlinearBeamColumn 4 2 4 $numIntgrPts 2 4
geomTransf Linear 5
element nonlinearBeamColumn 5 4 6 $numIntgrPts 1 5

# Getting Period
set eigs "[eigen 3]"
puts "Eigen Values:"
puts "$eigs"
for {set i 1} {$i<=[llength $eigs]} {incr i} {
set p [lappend p [expr 2*3.1415/pow([lindex $eigs [expr $i-1]],0.5)]]
}
puts "
Periods:"
puts "$p"

# Getting ModeShape
recorder Node -file Data/ModeShape1.out -node 2 4 6 -dof 1 "eigen 1"
recorder Node -file Data/ModeShape2.out -node 2 4 6 -dof 1 "eigen 2"
recorder Node -file Data/ModeShape3.out -node 2 4 6 -dof 1 "eigen 3"

pattern Plain 1 Linear {
eleLoad -ele 4 -type -beamUniform -1500
eleLoad -ele 5 -type -beamUniform -1500
}
constraints Plain
numberer Plain
system BandGeneral
test NormDispIncr 1.e-8 60
algorithm ModifiedNewton
integrator LoadControl 0.01
analysis Static
analyze 100
loadConst -time 0.0