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