eigen analysis

[zourguinadjib]

Good morning,

I have a problem with the eigen analysis ,i found a big value of the period (198.69 sec !!!) .I didn't know what's the problem (this is my first model in opensees).


My script is:


#In the name of ALLAH the beneficent the mercy full

#######################################################
# units: kN m sec
#######################################################

wipe ; # clear memory of all past model definitions
model BasicBuilder -ndm 3 -ndf 6; # Define the model builder, ndm=#dimension, ndf=#dofs

# InputtData ------------------------------------------
set recordNumber 1001;

set gmf .2

set H1 9.00
set H2 9.00
set H3 9.00
set L1 20.00
set L2 20.00
set DSec 1.000
set numBarsSecf 20
set numBarsSecs 20
set numBarsSect 20
set barAreaSec 8.040000e-004
set HBeam 0.5
set BBeam 10.000
set Fc 40000.00
set Fy 400000.00
set Es 2.000000e+008
set Fu 600000.00
set DeckMass 125
set GamaC 25
set g 9.81258
set PI 3.14159
set coverSec 0.05000
set coverB 0.05000
set Is 0.10
set Abeam 5.00000
set dir 2
set NumRecords 1
set Step 0.200
set MaxIM 3.000
#----------------------------------------------------------

# define NODAL COORDINATES ++++++++++++++++++++++++++
# columns bottom
node 02 $L1 0 [expr -($H1+$HBeam/2)]
node 03 $L1 0 [expr -($H1+$HBeam/2)]
node 04 $L1 0 [expr -($H1+$HBeam/2)]
# columns top
node 55 $L1 0 [expr -($HBeam/2)]
node 66 $L1 0 [expr -($HBeam/2)]
node 77 $L1 0 [expr -($HBeam/2)]
# abutments
node 01 0 0 0
node 08 [expr $L1+$L2] 0 0
# mass centers of deck
node 09 [expr 2*$L1/10.0] 0 0
node 10 [expr 4*$L1/10.0] 0 0
node 11 [expr 6*$L1/10.0] 0 0
node 12 [expr 8*$L1/10.0] 0 0
node 05 $L1 0 0
node 13 [expr $L1+2*$L2/10.0] 0 0
node 14 [expr $L1+4*$L2/10.0] 0 0
node 15 [expr $L1+6*$L2/10.0] 0 0
node 16 [expr $L1+8*$L2/10.0] 0 0
# BOUNDARY CONDITIONS ++++++++++++++++++++++++++++++++++
fix 01 1 1 1 1 1 1
fix 02 1 1 1 1 1 1
fix 03 1 1 1 1 1 1
fix 04 1 1 1 1 1 1
fix 08 1 1 1 1 1 1

equalDOF 05 55 1 2 3 4
equalDOF 05 66 1 2 3 4
equalDOF 05 77 1 2 3 4
equalDOF 05 07 1 2 3 4
equalDOF 05 06 1 2 3 4


# define Materials & Sections & ELEMENTS ---------------

source RCcircSection.tcl ; # procedure for definining RC fiber section

# set up geometric transformations of element
# separate columns and beams, in case of P-Delta analysis for columns
# in 3D model, assign vector vecxz
set IDColTransf 1; # all columns
set IDBeamTransf 2; # all beams

set ColTransfType PDelta ; # options, Linear PDelta Corotational
geomTransf $ColTransfType $IDColTransf 0 1 0 ; # only columns can have PDelta effects (gravity effects)
geomTransf Linear $IDBeamTransf 0 1 0; # beam

# Define Beam-Column Elements
set np 5; # number of Gauss integration points for nonlinear curvature distribution

# columns
element nonlinearBeamColumn 1 02 66 $np $ColSecTagf $IDColTransf; # first pier
element nonlinearBeamColumn 2 03 55 $np $ColSecTags $IDColTransf # second pier
element nonlinearBeamColumn 3 04 77 $np $ColSecTagt $IDColTransf; # third pier
## beams

set Ec [expr 1000*(.043*pow(101.97162*$GamaC,1.5)*sqrt(-$fc/1000))]; # Concrete Elastic Modulus( negtive is for -*- = + )
set AgBeam $Abeam; # rectuangular-Beam cross-sectional area
set IzBeam [expr $Is]; # about-local-z Rect-Beam cracked moment of inertial
set IyBeam 41.67; # about-local-y Rect-Beam cracked moment of inertial

element elasticBeamColumn 04 08 16 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;
element elasticBeamColumn 05 16 15 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;
element elasticBeamColumn 06 15 14 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;
element elasticBeamColumn 07 14 13 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;
element elasticBeamColumn 08 13 05 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;

element elasticBeamColumn 09 05 12 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;
element elasticBeamColumn 10 12 11 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;
element elasticBeamColumn 11 11 10 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;
element elasticBeamColumn 12 10 09 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;
element elasticBeamColumn 13 09 01 $AgBeam $Ec $Gc $J $IyBeam $IzBeam $IDBeamTransf;

# Define GRAVITY LOADS, weight and masses -----------------------------------------------------

set GammaConcrete $GamaC; # Reinforced-Concrete weight density (weight per volume)

set QdlCol [expr $GammaConcrete*$PI*pow($DSec,2)/4]; # self weight of Column, weight per length

set QdlBeam [expr $DeckMass];

set WeightColf [expr $QdlCol*$H1]; # total first Column weight
set WeightCols [expr $QdlCol*$H2]; # total second Column weight
set WeightColt [expr $QdlCol*$H3]; # total third Column weight

set WeightBeam04 [expr $g*$QdlBeam*2.0*$L1/10.0]; # total Beam weight
set WeightBeam09 [expr $g*$QdlBeam*2.0*$L2/10.0];

# assign masses to the nodes that the columns are connected to
# each connection takes the mass of 1/2 of each element framing into it (mass=weight/$g)
set M04 [expr $QdlBeam*2.0*$L1/10.0];
set M09 [expr $QdlBeam*2.0*$L2/10.0];

mass 09 [expr 2*$M04] [expr 2*$M04] 0. 0. 0. 0. ;
mass 11 [expr 2*$M04] [expr 2*$M04] 0. 0. 0. 0. ;
mass 05 [expr 2*$M04] [expr 2*$M04] 0. 0. 0. 0. ;
mass 14 [expr 2*$M04] [expr 2*$M04] 0. 0. 0. 0. ;
mass 16 [expr 2*$M04] [expr 2*$M04] 0. 0. 0. 0. ;

# eigen analysis ----------------------------------------------
set T1model [expr 2*$PI/(pow([eigen 1],0.5))]
puts "T1model=[expr $T1model]sec"

[IsmBaha]

line 100 -> semicolon

"element nonlinearBeamColumn 2 03 55 $np $ColSecTags $IDColTransf # second pier "

fix: element nonlinearBeamColumn 2 03 55 $np $ColSecTags $IDColTransf; # second pier

[zourguinadjib]

Thank you for this orientation but tdidn't understand the problem
What do you mean by fix: element...................

[IsmBaha]

you forgot to put semicolon ";" before the comment. You need to put ";" to finish the command line to write a comment with #. Change your line 100 as below and see it will change your result.

element nonlinearBeamColumn 2 03 55 $np $ColSecTags $IDColTransf; # second pier