Hi
i want to model 2d frame,for verify my model i want to compare period of mine with real period. period my model is 0.527 but real period is 0.94. please help me and say me my mistake.
# --------------------------------------------------------------------------------------------------
# Example 5. 2D Frame -- Build Model
# nonlinearBeamColumn element, uniaxial inelastic section
# Silvia Mazzoni & Frank McKenna, 2006
#
# SET UP ----------------------------------------------------------------------------
wipe; # clear memory of all past model definitions
model BasicBuilder -ndm 2 -ndf 3; # Define the model builder, ndm=#dimension, ndf=#dofs
set dataDir Data; # set up name of data directory (you can remove this)
file mkdir $dataDir; # create data directory
set GMdir "../GMfiles/"; # ground-motion file directory
set m 1.; # define basic units -- output units
set N 1.; # define basic units -- output units
set kg [expr $N*9.81];
set cm [expr $m*0.01];
set sec 1.; # define basic units -- output units
set PI [expr 3.14]; # define constants
set g [expr 9.81*$m/pow($sec,2)]; # gravitational acceleration
# define GEOMETRY -------------------------------------------------------------
# define structure-geometry paramters
set LCol [expr 3.66*$m]; # column height
set LCol1 [expr 4.57*$m]; # column height
set LBeam [expr 9.14*$m]; # beam length
# calculate locations of beam/column intersections:
set X1 0.;
set X2 [expr $X1 + $LBeam];
set X3 [expr $X2 + $LBeam];
set X4 [expr $X3 + $LBeam];
set X5 [expr $X4 + $LBeam];
set Y1 0.;
set Y2 [expr $Y1 + $LCol1];
set Y3 [expr $Y2 + $LCol];
set Y4 [expr $Y3 + $LCol];
set Y5 [expr $Y4 + $LCol];
# define nodal coordinates
node 1 $X1 $Y1
node 2 $X2 $Y1
node 3 $X3 $Y1
node 4 $X4 $Y1
node 5 $X5 $Y1
node 6 $X1 $Y2
node 7 $X2 $Y2
node 8 $X3 $Y2
node 9 $X4 $Y2
node 10 $X5 $Y2
node 11 $X1 $Y3
node 12 $X2 $Y3
node 13 $X3 $Y3
node 14 $X4 $Y3
node 15 $X5 $Y3
node 16 $X1 $Y4
node 17 $X2 $Y4
node 18 $X3 $Y4
node 19 $X4 $Y4
node 20 $X5 $Y4
node 21 $X1 $Y5
node 22 $X2 $Y5
node 23 $X3 $Y5
node 24 $X4 $Y5
node 25 $X5 $Y5
# Set up parameters that are particular to the model for displacement control
set IDctrlNode 21; # node where displacement is read for displacement control
set IDctrlDOF 1; # degree of freedom of displacement read for displacement control
set NStory 4; # number of stories above ground level
set NBay 4; # number of bays
set LBuilding $Y5; # total building height
# BOUNDARY CONDITIONS
fix 1 1 1 1
fix 2 1 1 1
fix 3 1 1 1
fix 4 1 1 1
fix 5 1 1 1
fix 6 0 0 0
fix 7 0 0 0
fix 8 0 0 0
fix 9 0 0 0
fix 10 0 0 0
fix 11 0 0 0
fix 12 0 0 0
fix 13 0 0 0
fix 14 0 0 0
fix 15 0 0 0
fix 16 0 0 0
fix 17 0 0 0
fix 18 0 0 0
fix 19 0 0 0
fix 20 0 0 0
fix 21 0 0 0
fix 22 0 0 0
fix 23 0 0 0
fix 24 0 0 0
fix 25 0 0 0
# Define ELEMENTS & SECTIONS -------------------------------------------------------------
set ColSecTag1 1; # assign a tag number to the column section tag
set ColMatTagFlex1 2; # assign a tag number to the column flexural behavior
set ColMatTagAxial1 3; # assign a tag number to the column axial behavior
set ColSecTag2 4; # assign a tag number to the column section tag
set ColMatTagFlex2 5; # assign a tag number to the column flexural behavior
set ColMatTagAxial2 6; # assign a tag number to the column axial behavior
set ColSecTag3 7; # assign a tag number to the column section tag
set ColMatTagFlex3 8; # assign a tag number to the column flexural behavior
set ColMatTagAxial3 9; # assign a tag number to the column axial behavior
set ColSecTag4 10; # assign a tag number to the column section tag
set ColMatTagFlex4 11; # assign a tag number to the column flexural behavior
set ColMatTagAxial4 12; # assign a tag number to the column axial behavior
set ColSecTag5 13; # assign a tag number to the column section tag
set ColMatTagFlex5 14; # assign a tag number to the column flexural behavior
set ColMatTagAxial5 15; # assign a tag number to the column axial behavior
set ColSecTag6 16; # assign a tag number to the column section tag
set ColMatTagFlex6 17; # assign a tag number to the column flexural behavior
set ColMatTagAxial6 18; # assign a tag number to the column axial behavior
set BeamSecTag1 19; # assign a tag number to the beam section tag
set BeamMatTagFlex1 20; # assign a tag number to the beam flexural behavior
set BeamMatTagAxial1 21; # assign a tag number to the beam axial behavior
set BeamSecTag2 22; # assign a tag number to the beam section tag
set BeamMatTagFlex2 23; # assign a tag number to the beam flexural behavior
set BeamMatTagAxial2 24; # assign a tag number to the beam axial behavior
set BeamSecTag3 25; # assign a tag number to the beam section tag
set BeamMatTagFlex3 26; # assign a tag number to the beam flexural behavior
set BeamMatTagAxial3 27; # assign a tag number to the beam axial behavior
set BeamSecTag4 28; # assign a tag number to the beam section tag
set BeamMatTagFlex4 29; # assign a tag number to the beam flexural behavior
set BeamMatTagAxial4 30; # assign a tag number to the beam axial behavior
# define MATERIAL properties ----------------------------------------
set Fy [expr 345e6*$N/pow($m,2)]
set Es [expr 2e11*$N/pow($m,2)]; # Steel Young's Modulus
set nu 0.3;
set Gs [expr $Es/2./[expr 1+$nu]]; # Torsional stiffness Modulus
# define ELEMENTS
# set up geometric transformations of element
# separate columns and beams, in case of P-Delta analysis for columns
set IDColTransf 1; # all columns
set IDBeamTransf 2; # all beams
#set ColTransfType PDelta ; # options, Linear PDelta Corotational
geomTransf PDelta $IDColTransf ; # only columns can have PDelta effects (gravity effects)
geomTransf Linear $IDBeamTransf;
-----------------------------------------------------------------------
# COLUMN section W14x233(1)
set AgCol1 [expr 0.0442*pow($m,2)];
set IzCol1 [expr 1.2533e-3*pow($m,4)];
set SCol1 [expr 6.166e-3*pow($m,3)];
set EICol1 [expr $Es*$IzCol1]; # EI, for moment-curvature relationship
set EACol1 [expr $Es*$AgCol1]; # EA, for axial-force-strain relationship
set MyCol1 [expr $SCol1*$Fy]; # yield moment
set b 0.01 ;
uniaxialMaterial Steel01 $ColMatTagFlex1 $MyCol1 $EICol1 $b;
uniaxialMaterial Elastic $ColMatTagAxial1 $EACol1;
section Aggregator $ColSecTag1 $ColMatTagAxial1 P $ColMatTagFlex1 Mz;
---------
# COLUMN section W14x193(2)
set AgCol2 [expr 0.0366*pow($m,2)];
set IzCol2 [expr 9.99e-4*pow($m,4)];
set SCol2 [expr 5.075e-3*pow($m,3)];
set EICol2 [expr $Es*$IzCol2];
set EACol2 [expr $Es*$AgCol2]; # EA, for axial-force-strain relationship
set MyCol2 [expr $SCol2*$Fy];
uniaxialMaterial Steel01 $ColMatTagFlex2 $MyCol2 $EICol2 $b;
uniaxialMaterial Elastic $ColMatTagAxial2 $EACol2;
section Aggregator $ColSecTag2 $ColMatTagAxial2 P $ColMatTagFlex2 Mz;
-----------------------------------------------------------------------
# COLUMN section W14x99(3)
set AgCol3 [expr 0.0188*pow($m,2)];
set IzCol3 [expr 4.62e-4*pow($m,4)];
set SCol3 [expr 2.562e-3*pow($m,3)];
set EICol3 [expr $Es*$IzCol3]; # EI, for moment-curvature relationship
set EACol3 [expr $Es*$AgCol3]; # EA, for axial-force-strain relationship
set MyCol3 [expr $SCol3*$Fy]; # yield moment
set b 0.01 ;
uniaxialMaterial Steel01 $ColMatTagFlex3 $MyCol3 $EICol3 $b; # bilinear behavior for flexure
uniaxialMaterial Elastic $ColMatTagAxial3 $EACol3;
section Aggregator $ColSecTag3 $ColMatTagAxial3 P $ColMatTagFlex3 Mz;
---------------------------------------
# COLUMN section W14x74(4)
set AgCol4 [expr 0.0141*pow($m,2)];
set IzCol4 [expr 3.309e-4*pow($m,4)];
set SCol4 [expr 1.835e-3*pow($m,3)];
set EICol4 [expr $Es*$IzCol4]; # EI, for moment-curvature relationship
set EACol4 [expr $Es*$AgCol4]; # EA, for axial-force-strain relationship
set MyCol4 [expr $SCol4*$Fy]; # yield moment
set b 0.01 ;
uniaxialMaterial Steel01 $ColMatTagFlex4 $MyCol4 $EICol4 $b;
uniaxialMaterial Elastic $ColMatTagAxial4 $EACol4;
section Aggregator $ColSecTag4 $ColMatTagAxial4 P $ColMatTagFlex4 Mz;)
----------------------
# COLUMN section W14x176(5)
set AgCol5 [expr 0.0334*pow($m,2)];
set IzCol5 [expr 8.907e-4*pow($m,4)];
set SCol5 [expr 4.614e-3*pow($m,3)];
set EICol5 [expr $Es*$IzCol5]; # EI, for moment-curvature relationship
set EACol5 [expr $Es*$AgCol5]; # EA, for axial-force-strain relationship
set MyCol5 [expr $SCol5*$Fy]; # yield moment
set b 0.01 ;
uniaxialMaterial Steel01 $ColMatTagFlex5 $MyCol5 $EICol5 $b; # bilinear behavior for flexure
uniaxialMaterial Elastic $ColMatTagAxial5 $EACol5;
section Aggregator $ColSecTag5 $ColMatTagAxial5 P $ColMatTagFlex5 Mz; ------------------------
# COLUMN section W14x311(6)
set AgCol6 [expr 0.059*pow($m,2)];
set IzCol6 [expr 1.802e-3*pow($m,4)];
set SCol6 [expr 8.299e-3*pow($m,3)];
set EICol6 [expr $Es*$IzCol6]; # EI, for moment-curvature relationship
set EACol6 [expr $Es*$AgCol6]; # EA, for axial-force-strain relationship
set MyCol6 [expr $SCol6*$Fy]; # yield moment
set b 0.01 ;
uniaxialMaterial Steel01 $ColMatTagFlex6 $MyCol6 $EICol6 $b; # bilinear behavior for flexure
uniaxialMaterial Elastic $ColMatTagAxial6 $EACol6;
section Aggregator $ColSecTag6 $ColMatTagAxial6 P $ColMatTagFlex6 Mz;
---------------------------------------
# BEAM section W24x68(1)
set AgBeam1 [expr 0.013*pow($m,2)]; # cross-sectional area
set IzBeam1 [expr 7.617e-4*pow($m,4)]; # moment of Inertia
set SBeam1 [expr 2.531e-3*pow($m,3)]; # moment of Inertia
set EIBeam1 [expr $Es*$IzBeam1]; # EI, for moment-curvature relationship
set EABeam1 [expr $Es*$AgBeam1]; # EA, for axial-force-strain relationship
set MyBeam1 [expr $SBeam1*$Fy]; # yield moment
set b 0.01 ;
uniaxialMaterial Steel01 $BeamMatTagFlex1 $MyBeam1 $EIBeam1 $b;
uniaxialMaterial Elastic $BeamMatTagAxial1 $EABeam1;
section Aggregator $BeamSecTag1 $BeamMatTagAxial1 P $BeamMatTagFlex1 Mz;
---------------------------------
# BEAM section W27x94(2)
set AgBeam2 [expr 0.0179*pow($m,2)]; # cross-sectional area
set IzBeam2 [expr 1.361e-3*pow($m,4)]; # moment of Inertia
set SBeam2 [expr 3.984e-3*pow($m,3)]; # moment of Inertia
set EIBeam2 [expr $Es*$IzBeam2]; # EI, for moment-curvature relationship
set EABeam2 [expr $Es*$AgBeam2]; # EA, for axial-force-strain relationship
set MyBeam2 [expr $SBeam2*$Fy]; # yield moment
set b 0.01 ;
uniaxialMaterial Steel01 $BeamMatTagFlex2 $MyBeam2 $EIBeam2 $b;
uniaxialMaterial Elastic $BeamMatTagAxial2 $EABeam2;
section Aggregator $BeamSecTag2 $BeamMatTagAxial2 P $BeamMatTagFlex2 Mz;
-----------------------------
# BEAM section W27x114(3)
set AgBeam3 [expr 0.0216*pow($m,2)]; # cross-sectional area
set IzBeam3 [expr 1.698e-3*pow($m,4)]; # moment of Inertia
set SBeam3 [expr 4.898e-3*pow($m,3)]; # moment of Inertia
set EIBeam3 [expr $Es*$IzBeam3]; # EI, for moment-curvature relationship
set EABeam3 [expr $Es*$AgBeam3]; # EA, for axial-force-strain relationship
set MyBeam3 [expr $SBeam3*$Fy]; # yield moment
set b 0.01 ;
uniaxialMaterial Steel01 $BeamMatTagFlex3 $MyBeam3 $EIBeam3 $b;
uniaxialMaterial Elastic $BeamMatTagAxial3 $EABeam3;
section Aggregator $BeamSecTag3 $BeamMatTagAxial3 P $BeamMatTagFlex3 Mz;
-----------------------------------------------
# BEAM section W33x130(4)
set AgBeam4 [expr 0.0247*pow($m,2)]; # cross-sectional area
set IzBeam4 [expr 2.793e-3*pow($m,4)]; # moment of Inertia
set SBeam4 [expr 6.644e-3*pow($m,3)]; # moment of Inertia
set EIBeam4 [expr $Es*$IzBeam4]; # EI, for moment-curvature relationship
set EABeam4 [expr $Es*$AgBeam4]; # EA, for axial-force-strain relationship
set MyBeam4 [expr $SBeam4*$Fy]; # yield moment
set b 0.01 ; # strain-hardening ratio (ratio between post-yield tangent and initial elastic tangent)
uniaxialMaterial Steel01 $BeamMatTagFlex4 $MyBeam4 $EIBeam4 $b;
uniaxialMaterial Elastic $BeamMatTagAxial4 $EABeam4;
section Aggregator $BeamSecTag4 $BeamMatTagAxial4 P $BeamMatTagFlex4 Mz;
#-----------------------------------------------
# Define Beam-Column Elements
set np 5; # number of Gauss integration points for nonlinear curvature distribution
# columns
element nonlinearBeamColumn 1 1 6 $np $ColSecTag1 $IDColTransf;
element nonlinearBeamColumn 2 2 7 $np $ColSecTag6 $IDColTransf;
element nonlinearBeamColumn 3 3 8 $np $ColSecTag6 $IDColTransf;
element nonlinearBeamColumn 4 4 9 $np $ColSecTag6 $IDColTransf;
element nonlinearBeamColumn 5 5 10 $np $ColSecTag1 $IDColTransf;
#-----------#level 2
element nonlinearBeamColumn 10 6 11 $np $ColSecTag2 $IDColTransf;
element nonlinearBeamColumn 11 7 12 $np $ColSecTag6 $IDColTransf;
element nonlinearBeamColumn 12 8 13 $np $ColSecTag6 $IDColTransf;
element nonlinearBeamColumn 13 9 14 $np $ColSecTag6 $IDColTransf;
element nonlinearBeamColumn 14 10 15 $np $ColSecTag2 $IDColTransf;
#-----------#level 3
element nonlinearBeamColumn 19 11 16 $np $ColSecTag3 $IDColTransf;
element nonlinearBeamColumn 20 12 17 $np $ColSecTag5 $IDColTransf;
element nonlinearBeamColumn 21 13 18 $np $ColSecTag5 $IDColTransf;
element nonlinearBeamColumn 22 14 19 $np $ColSecTag5 $IDColTransf;
element nonlinearBeamColumn 23 15 20 $np $ColSecTag3 $IDColTransf;
#------------#level 4
element nonlinearBeamColumn 28 16 21 $np $ColSecTag4 $IDColTransf;
element nonlinearBeamColumn 29 17 22 $np $ColSecTag4 $IDColTransf;
element nonlinearBeamColumn 30 18 23 $np $ColSecTag4 $IDColTransf;
element nonlinearBeamColumn 31 19 24 $np $ColSecTag4 $IDColTransf;
element nonlinearBeamColumn 32 20 25 $np $ColSecTag4 $IDColTransf;
#----------------------------------------------------#beams
element nonlinearBeamColumn 6 6 7 $np $BeamSecTag4 $IDBeamTransf;
element nonlinearBeamColumn 7 7 8 $np $BeamSecTag4 $IDBeamTransf;
element nonlinearBeamColumn 8 8 9 $np $BeamSecTag4 $IDBeamTransf;
element nonlinearBeamColumn 9 9 10 $np $BeamSecTag4 $IDBeamTransf;
#beam leve2------------------------
element nonlinearBeamColumn 15 11 12 $np $BeamSecTag3 $IDBeamTransf;
element nonlinearBeamColumn 16 12 13 $np $BeamSecTag3 $IDBeamTransf;
element nonlinearBeamColumn 17 13 14 $np $BeamSecTag3 $IDBeamTransf;
element nonlinearBeamColumn 18 14 15 $np $BeamSecTag3 $IDBeamTransf;#beam level3-------------------------------------------------------
element nonlinearBeamColumn 24 16 17 $np $BeamSecTag2 $IDBeamTransf;
element nonlinearBeamColumn 25 17 18 $np $BeamSecTag2 $IDBeamTransf;
element nonlinearBeamColumn 26 18 19 $np $BeamSecTag2 $IDBeamTransf;
element nonlinearBeamColumn 27 19 20 $np $BeamSecTag2 $IDBeamTransf;
#beam level4-------------------------------------------------------
element nonlinearBeamColumn 33 21 22 $np $BeamSecTag1 $IDBeamTransf;
element nonlinearBeamColumn 34 22 23 $np $BeamSecTag1 $IDBeamTransf;
element nonlinearBeamColumn 35 23 24 $np $BeamSecTag1 $IDBeamTransf;
element nonlinearBeamColumn 36 24 25 $np $BeamSecTag1 $IDBeamTransf;
#----------------------------------------------------------------------
set loadstorylive [expr 2395*$N/pow($m,2)];
set loadstorydead [expr 5555*$N/pow($m,2)];
set loadstory [expr 0.25*$loadstorylive+$loadstorydead];
set loadstory1 [expr $loadstorylive+$loadstorydead];
set Lslab [expr $LBeam/2]; # assume slab extends a distance of $LBeam1/2 in/out of plane
set QBeamstory [expr $loadstory*$Lslab];
set QBeamstory1 [expr $loadstory1*$Lslab];
set loadRoofdead [expr 3640*$N/pow($m,2)];
set loadRooflive [expr 960*$N/pow($m,2)];
set loadRoof [expr $loadRooflive*0.25+$loadRoofdead ];
set loadRoof1 [expr $loadRooflive+*$loadRoofdead ];
set QBeamRoof [expr $loadRoof*$Lslab];
set QBeamRoof1 [expr $loadRoof1*$Lslab];
# 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/$g)
mass 6 [expr ($QBeamstory/2*$LBeam)/$g] 0 0.;
mass 7 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 8 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 9 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 10 [expr ($QBeamstory/2*$LBeam)/$g] 0 0.;
mass 11 [expr ($QBeamstory/2*$LBeam)/$g] 0 0.;
mass 12 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 13 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 14 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 15 [expr ($QBeamstory/2*$LBeam)/$g] 0 0.;
mass 16 [expr ($QBeamstory/2*$LBeam)/$g] 0 0.;
mass 17 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 18 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 19 [expr ($QBeamstory*$LBeam)/$g] 0 0.;
mass 20 [expr ($QBeamstory/2*$LBeam)/$g] 0 0.;
mass 21 [expr ($QBeamRoof/2*$LBeam)/$g] 0 0.;
mass 22 [expr ($QBeamRoof*$LBeam)/$g] 0 0.;
mass 23 [expr ($QBeamRoof*$LBeam)/$g] 0 0.;
mass 24 [expr ($QBeamRoof*$LBeam)/$g] 0 0.;
mass 25 [expr ($QBeamRoof/2*$LBeam)/$g] 0 0.;
puts "Model Built"
# define GRAVITY -------------------------------------------------------------
# GRAVITY LOADS # define gravity load applied to beams and columns -- eleLoad applies loads in local coordinate axis
pattern Plain 1 Linear {
load 6 0. [expr (-1*$QBeamstory1/2*$LBeam)] 0. 0. 0. 0 ;
load 7 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 8 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 9 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 10 0. [expr (-1*$QBeamstory1/2*$LBeam)] 0. 0. 0. 0 ;
load 11 0. [expr (-1*$QBeamstory1/2*$LBeam)] 0. 0. 0. 0 ;
load 12 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 13 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 14 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 15 0. [expr (-1*$QBeamstory1/2*$LBeam)] 0. 0. 0. 0 ;
load 16 0. [expr (-1*$QBeamstory1/2*$LBeam)] 0. 0. 0. 0 ;
load 17 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 18 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 19 0. [expr (-1*$QBeamstory1*$LBeam)] 0. 0. 0. 0 ;
load 20 0. [expr (-1*$QBeamstory1/2*$LBeam)] 0. 0. 0. 0 ;
load 21 0. [expr (-1*$QBeamRoof1/2*$LBeam)] 0. 0. 0. 0 ;
load 22 0. [expr (-1*$QBeamRoof1*$LBeam)] 0. 0. 0. 0 ;
load 23 0. [expr (-1*$QBeamRoof1*$LBeam)] 0. 0. 0. 0 ;
load 24 0. [expr (-1*$QBeamRoof1*$LBeam)] 0. 0. 0. 0 ;
load 25 0. [expr (-1*$QBeamRoof1/2*$LBeam)] 0. 0. 0. 0 ;
}
# Gravity-analysis parameters -- load-controlled static analysis
set Tol 1.0e-8; # convergence tolerance for test
variable constraintsTypeGravity Plain; # default;
if { [info exists RigidDiaphragm] == 1} {
if {$RigidDiaphragm=="ON"} {
variable constraintsTypeGravity Lagrange; # large model: try Transformation
}; # if rigid diaphragm is on
}; # if rigid diaphragm exists
constraints $constraintsTypeGravity ; # how it handles boundary conditions
numberer RCM; # renumber dof's to minimize band-width (optimization), if you want to
system BandGeneral ; # how to store and solve the system of equations in the analysis (large model: try UmfPack)
test NormDispIncr $Tol 6 ; # determine if convergence has been achieved at the end of an iteration step
algorithm Newton; # use Newton's solution algorithm: updates tangent stiffness at every iteration
set NstepGravity 10; # apply gravity in 10 steps
set DGravity [expr 1./$NstepGravity]; # first load increment;
integrator LoadControl $DGravity; # determine the next time step for an analysis
analysis Static; # define type of analysis static or transient
analyze $NstepGravity; # apply gravity
# ------------------------------------------------- maintain constant gravity loads and reset time to zero
loadConst -time 0.0
puts "Model Built"
set lambda [eigen 1]
set omega [expr pow($lambda,0.5)]
set Tperiod [expr 2*$PI/$omega];
period of structure
Moderators: silvia, selimgunay, Moderators
without knowing your structure it is impossible to tell you why there is a difference .. as your model is basically elastic, why don't you just model using elasticBeamColumns until you figure out what is up, i.e. is your model really fixed at the base, are your joints really rigid,
..., ....,
ps. if a node is not constrained you do not need to have a fix command for it, by default they are all assumed to be free.
pps. and as all your units are provided in N and m you can remove all the units from the script .. they are only useful if you want to mix things (like provinding W section properties in inch and let program take care of conversion).
..., ....,
ps. if a node is not constrained you do not need to have a fix command for it, by default they are all assumed to be free.
pps. and as all your units are provided in N and m you can remove all the units from the script .. they are only useful if you want to mix things (like provinding W section properties in inch and let program take care of conversion).