Rigid Diaphragm Consequences
foreach rigidConstraint {no yes} {
puts "RIGID CONSTRAINT: $rigidConstraint"
foreach matType {steel concrete} {
foreach eleType {forceBeamColumn dispBeamColumn} {
wipe
# create model builder
model basic -ndm 2 -ndf 3
set width 360
set height 144
# create nodes
node 1 0.0 0.0
node 2 $width 0.0
node 3 0.0 $height
node 4 $width $height
# Fix supports at base of columns
# tag DX DY RZ
fix 1 1 1 1
fix 2 1 1 1
if {$rigidConstraint == "yes"} {
equalDOF 3 4 1
}
if {$matType == "concrete"} {
# CONCRETE tag f'c ec0 f'cu ecu
# Core concrete (confined)
uniaxialMaterial Concrete01 1 -6.0 -0.004 -5.0 -0.014
# Cover concrete (unconfined)
uniaxialMaterial Concrete01 2 -5.0 -0.002 0.0 -0.006
# STEEL
# Reinforcing steel
set fy 60.0; # Yield stress
set E 30000.0; # Young's modulus
# tag fy E0 b
uniaxialMaterial Steel01 3 $fy $E 0.01
} else {
set fy 60.0; # Yield stress
set E 30000.0; # Young's modulus
# tag fy E0 b
uniaxialMaterial Steel01 1 $fy $E 0.01
uniaxialMaterial Steel01 2 $fy $E 0.01
uniaxialMaterial Steel01 3 $fy $E 0.01
}
# Define cross-section for nonlinear columns
# ------------------------------------------
# set some paramaters
set colWidth 15
set colDepth 24
set cover 1.5
set As 0.60; # area of no. 7 bars
# some variables derived from the parameters
set y1 [expr $colDepth/2.0]
set z1 [expr $colWidth/2.0]
section Fiber 1 {
# Create the concrete core fibers
patch rect 1 10 1 [expr $cover-$y1] [expr $cover-$z1] [expr $y1-$cover] [expr $z1-$cover]
# Create the concrete cover fibers (top, bottom, left, right)
patch rect 2 10 1 [expr -$y1] [expr $z1-$cover] $y1 $z1
patch rect 2 10 1 [expr -$y1] [expr -$z1] $y1 [expr $cover-$z1]
patch rect 2 2 1 [expr -$y1] [expr $cover-$z1] [expr $cover-$y1] [expr $z1-$cover]
patch rect 2 2 1 [expr $y1-$cover] [expr $cover-$z1] $y1 [expr $z1-$cover]
# Create the reinforcing fibers (left, middle, right)
layer straight 3 3 $As [expr $y1-$cover] [expr $z1-$cover] [expr $y1-$cover] [expr $cover-$z1]
layer straight 3 2 $As 0.0 [expr $z1-$cover] 0.0 [expr $cover-$z1]
layer straight 3 3 $As [expr $cover-$y1] [expr $z1-$cover] [expr $cover-$y1] [expr $cover-$z1]
}
# Define elements
# ----------------------
geomTransf Linear 1
set np 5
# Create the coulumns using Beam-column elements
# e tag ndI ndJ nsecs secID transfTag
element $eleType 1 1 3 $np 1 1
element $eleType 2 2 4 $np 1 1
element $eleType 3 3 4 $np 1 1
# Define gravity loads
# --------------------
# Set a parameter for the axial load
set P 180; # 10% of axial capacity of columns
# Create a Plain load pattern with a Linear TimeSeries
pattern Plain 1 "Linear" {
# Create nodal loads at nodes 3 & 4
# nd FX FY MZ
load 3 0.0 [expr -$P] 0.0
load 4 0.0 [expr -$P] 0.0
}
system BandGeneral
constraints Transformation
numberer RCM
test NormDispIncr 1.0e-12 10 3
algorithm Newton
integrator LoadControl 0.1
analysis Static
analyze 10
loadConst -time 0.0
pattern Plain 2 "Linear" {
load 3 1.0 0.0 0.0
load 4 1.0 0.0 0.0
}
integrator DisplacementControl 3 1 0.1
analyze 10
set strains [eleResponse 3 basicDeformation]
set forces [eleResponse 3 forces]
puts "eleType: $eleType matType $matType axialForce [lindex $forces 0] axialDeformation: [lindex $strains 0]"
}
}
}and the results when this script is run are:
RIGID CONSTRAINT: no
eleType: forceBeamColumn matType steel axialForce -0.08875612010504939364 axialDeformation: 0.00000291960921383616
eleType: dispBeamColumn matType steel axialForce -0.00000000000010219973 axialDeformation: 0.00000000000000000000
eleType: forceBeamColumn matType concrete axialForce 1.25405861627505310629 axialDeformation: 0.12918648354852413362
eleType: dispBeamColumn matType concrete axialForce 3.61866611884458500015 axialDeformation: 0.17247077365271457072
RIGID CONSTRAINT: yes
eleType: forceBeamColumn matType steel axialForce -0.00000000000010287569 axialDeformation: 0.00000000000000000000
eleType: dispBeamColumn matType steel axialForce -0.00000000000013310834 axialDeformation: 0.00000000000000000000
eleType: forceBeamColumn matType concrete axialForce 186.25340185913745472135 axialDeformation: 0.00000000000000000000
eleType: dispBeamColumn matType concrete axialForce 163.64106186688189836786 axialDeformation: 0.00000000000000000000