pretensioning

[milenamassari]

Hi,
I need help please..I don't know how modelling pretension: I've two steel bars with pretension that I've to transfer to a concrete beam column, the bars are external and I would give pretension to this bars and connect them to the beam and while those sretch the other is shortened.Thanks!

PS: sorry for the incorrect english. I'm italian...

[fmk]

look at steel02 with init stress.

[milenamassari]

Hi! I've a problem with the solution, there i something strange with the strain on the connection between the little layer of mortar at the base and the column and I don't know how to resolve it because what I want it's that the column can rotate with the lateral displacement load while the mortar not (no traction resistance too) and since the column is rotating on the mortar section, the part in conctat is reduced and that's give problem..I attach a part of the script, please HELP ME!!!!

# units: kip, inch

# SET UP ----------------------------------------------------------------
wipe; # clear opensees model
set dataDir Data
file mkdir $dataDir
model basic -ndm 2 -ndf 3; # 2 dimensions, 3 dof per node

# define GEOMETRY
#-------------------------------------------------------------
# nodal coordinates:

node 1 0. 0.; # fixed base node column and mortar
node 2 0. 1.; # mortar
node 3 0. 15.5; # master node for dissipator
node 4 0. 35.; # last node column
node 23 0. 45.;

# nodal coordinates for the external dissipators:

node 11 0. 0.; # fixed base node of central dissipator
node 12 0. 15.5; # top node of centrdissip
node 13 -9.95 0.; # fixed base node to the left dissipator
node 14 -9.95 15.5; # top node of leftdissip
node 15 9.95 0.; # fixed base node to the right dissipator
node 16 9.95 15.5; # top node of rightdissip
node 17 0. 3.; # middle node in centraldissip
node 18 0. 9.5; # middle node in centraldissip
node 19 -9.95 3.; # middle node in leftdissip
node 20 -9.95 9.5; # middle node in leftdissip
node 21 9.95 3.; # middle node in rightdissip
node 22 9.95 9.5; # middle node in rightdissip

# Single point constraints -- Boundary Conditions
# I fixed all the dof's nodes at the base of each element in the model
fix 1 1 1 1;
fix 11 1 1 1;
fix 13 1 1 1;
fix 15 1 1 1;



#------- rigidLink ---------

rigidLink beam 3 14; # tying between column and left dissip
rigidLink beam 3 16; # tying between column and right dissip
equalDOF 3 12 1 2 3; # tying between column and central dissip
equalDOF 4 23 1 2 3; # tying between column and loading point

#Define materials for linear column
#---------------------------------------
set reinfconcTag 1; # tag reinforced concrete material
set mortarTag 2; # tag mortar material
set fpc -9;
set epsc0 -0.0027;
set fpcu -1.3;
set epsU -0.012;
set matTagk 3; # tag spring material
set Ek 35; # experimental modulus for rubber

#CONCRETE tag f'c ec0 f'cu ecu lambda ft Ets
#Concrete annulus (confined)
uniaxialMaterial Concrete02 $reinfconcTag -15.6 -0.01281 -6.5 -0.036 0.1 0.94 257
#Mortar at the base of the column
uniaxialMaterial Concrete01 $mortarTag $fpc $epsc0 $fpcu $epsU

#STEEL
#steel PT bars
set PTTag 4; # tag PT steelmaterial
set fy 120.0; # yield stress
set E 29000.0; # Young's modulus
set a2 1.;
set a1 [expr $a2*($fy/$E)];
#steel Outer Shell
set ShellTag 5; # tag Shellmaterial
set fysh 50; # yield stress
set Esh 29000; # Young's modulus
set bsh 0.01;


uniaxialMaterial Steel02 $ShellTag $fysh $Esh $bsh 18. 0.925 0.15


# section GEOMETRY -------------------------------------------------------------
set SecTag 10; # set tag for column
set SecTagm 20; # set tag for mortar

#
set ri 6; # inner radius of the section, only for hollow sections concrete
set ro 10; # overall (outer) radius of the section concrete
set ri1 10; # inner radius section steel
set ro1 10.25; # overall radius section steel
set nfCoreR 10; # number of radial divisions in the core (number of "rings")
set nfCoreT 60; # number of theta divisions in the core (number of "wedges")
set nfSteelT 60; # number of theta divisions in the shell (number of "wedges")
set nfSteelR 1; # number of radial divisions in the shell (number of "rings")


# Define the fiber section coloumn
section fiberSec $SecTag {
patch circ $reinfconcTag $nfCoreT $nfCoreR 0 0 $ri $ro 0. 360.; # Define the core patch
patch circ $ShellTag $nfSteelT $nfSteelR 0 0 $ri1 $ro1 0. 360.; # Define the shell patch

}

# Define the fiber section mortar
section fiberSec $SecTagm {
patch circ $mortarTag $nfCoreT $nfCoreR 0 0 $ri $ro 0. 360.; # Define the mortar patch
}

#Define geometric trasformation
geomTransf Linear 100; #????


#---Mortar Column----
set MortarColumn 1;
set numIntgrPts 5;

element dispBeamColumn $MortarColumn 1 2 2 $SecTagm 100; # Mortar element ATTENTION!!!

#----Column-----
set AColumn 2;
set BColumn 3;

element dispBeamColumn $AColumn 2 3 $numIntgrPts $SecTag 100; #Divided column
element dispBeamColumn $BColumn 3 4 $numIntgrPts $SecTag 100;


# -----------Define materials for dissipator elements------------
set IDmatTagAxial8 1000; # tag stee02 material for axial behavior of the 8 section
set IDmatTagMoment8 1001; # tag for the Mz to add at the same section above
set IDmatTagTorsion 1002; # tag for the tortional effect (not necessary in plane case)
set IDmatTagAxial4 1003; # tag stee02 material for axial behavior of the 4 section
set IDmatTagMoment4 1004; # tag for the Mz to add at the same section above
set Fy 60; # yeld stress dissipator
set Ex 29000; # young modulus dissipator
set Diam8 1.; # diameter part 8 dissipator
set Diam4 0.5; # diameter part 4 dissipator
set r [expr $Diam8/2.0]; # dissipator 8 radius
set r4 [expr $Diam4/2.0]; # dissipator 4 radius
set A [expr $r**2*3.14]; # dissip 8 area
set FyA [expr $Fy *$A]; # yeld stress multiplied by the section area
set A4 [expr $r4**2*3.14]; # dissip 4 area
set FyA4 [expr $Fy *$A4]; # yeld stress multiplied by the section area
set I [expr $r**4*3.14/4.0]; # Inertia 8
set I4 [expr $r4**4*3.14/4.0]; # Inertia 4
set EI [expr $Ex*$I]; # young modulus multiplied by the inertia
set EI4 [expr $Ex*$I4]; # young modulus multiplied by the inertia
set AE [expr $Ex*$A]; # young modulus multiplied by the area
set AE4 [expr $Ex*$A4]; # young modulus multiplied by the area
#set GJ 1.0e5;

uniaxialMaterial Steel02 $IDmatTagAxial8 $FyA $AE $bsh 18. 0.925 0.15;
uniaxialMaterial Elastic $IDmatTagMoment8 $EI;
#uniaxialMaterial Elastic $IDmatTagTorsion $GJ
uniaxialMaterial Steel02 $IDmatTagAxial4 $FyA4 $AE4 $bsh 18. 0.925 0.15;
uniaxialMaterial Elastic $IDmatTagMoment4 $EI4;



# -----------------Define section for dissipator-------------------
set SecTagDiss1 101;
set SecTagDiss2 102;
set SecTagDiss3 103;
set SecTagDiss4 104;

#----Section Properties-----
section Uniaxial $SecTagDiss1 $IDmatTagAxial8 P; # Define uniaxial section (8) with the property of steel02 previously determined
section Aggregator $SecTagDiss2 $IDmatTagMoment8 Mz -section $SecTagDiss1; # Add to the uniaxial material above Mz
section Uniaxial $SecTagDiss3 $IDmatTagAxial4 P; # Define uniaxial section (4) with the property of steel02 previously determined
section Aggregator $SecTagDiss4 $IDmatTagMoment4 Mz -section $SecTagDiss3; # Add to the uniaxial material above Mz


# Define elements
# ---------------
# Create dissipator elements

set NumIntgrPts 3; # number of integration point dissipator element

set DCenterA 6;
set DCenterB 7;
set DCenterC 8;

element dispBeamColumn $DCenterA 11 17 $NumIntgrPts $SecTagDiss2 100; # Central dissipator divided into three parts cause different areas
element dispBeamColumn $DCenterB 17 18 $NumIntgrPts $SecTagDiss4 100;
element dispBeamColumn $DCenterC 18 12 $NumIntgrPts $SecTagDiss2 100;


set DLeftA 9;
set DLeftB 10;
set DLeftC 11;

element dispBeamColumn $DLeftA 13 19 $NumIntgrPts $SecTagDiss2 100; # Left dissipator divided into three parts cause different areas
element dispBeamColumn $DLeftB 19 20 $NumIntgrPts $SecTagDiss4 100;
element dispBeamColumn $DLeftC 20 14 $NumIntgrPts $SecTagDiss2 100;


set DRightA 12;
set DRightB 13;
set DRightC 14;

element dispBeamColumn $DRightA 15 21 $NumIntgrPts $SecTagDiss2 100; # Right dissipator divided into three parts cause different areas
element dispBeamColumn $DRightB 21 22 $NumIntgrPts $SecTagDiss4 100;
element dispBeamColumn $DRightC 22 16 $NumIntgrPts $SecTagDiss2 100;

# CYCLIC LATERAL LOAD -------------------------------------------------------------
pattern Plain 2 Linear {
load 4 0. -315. 0.0
}


constraints Transformation; # how it handles boundary conditions
numberer Plain; # renumber dof's to minimize band-width (optimization), if you want to
system ProfileSPD; # how to store and solve the system of equations in the analysis
integrator LoadControl 0.1
test EnergyIncr 1.0e-6 1000 1; # determine if convergence has been achieved at the end of an iteration step
algorithm Newton -initial; # use Newton's solution algorithm: updates tangent stiffness at every iteration
analysis Static;
analyze 10
puts "Done Gravity"

loadConst -time 0.
# CYCLIC LATERAL LOAD -------------------------------------------------------------
pattern Plain 1 Linear {
load 23 1. 0. 0.0
}

set ok 0
integrator DisplacementControl 23 1 0.00001;
analysis Static;
set ok [analyze 270000];
if {$ok < 0} {
set nodeDisp23_d1 [nodeDisp 23 1];
puts "nodeDisp23_d1 = $nodeDisp23_d1 "
after 2000
set ok 0
integrator DisplacementControl 23 1 0.000001;
analysis Static;
set ok [analyze 2700000]
}

if {$ok < 0} {
set nodeDisp23_d2 [nodeDisp 23 1];
puts "nodeDisp23_d2 = $nodeDisp23_d2 "
puts "problem"

}

set nodeDisp23 [nodeDisp 23 1];
puts "nodeDisp23 = $nodeDisp23 "
puts "cycle 1"



puts "Done!"
wipe

THANKS!!!!!