Modelling springs for plastic hinge of column/beam

[venkateshyadav]

aylsworth wrote:
> selimgunay wrote:
> > I don't think you need to use the section aggregator as there is no section
> > used in the zerolength element. That may be the source of the problem.
>
> Ah yes. Sorry I forgot to mention that my element is beamwithhinge then the axial
> spring is integrated to this element. Then shear and rotation is on zeroloength.
> Though I am not sure if the code below is correct.
>
> #Axial Spring Parameters
> limitCurve Axial $axialCurveTag $zeroLengthElement [expr
> $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $ka $Pr 2 2 1 3 1 2 0 0
> uniaxialMaterial LimitState $ColMatTagAxial $Py $Pdy $Pu $Pdu $Pu $Pdu [expr -$Py]
> [expr -$Pdy] [expr -$Pu] [expr -$Pdu] [expr -$Pu] [expr -$Pdu] 0 0 0 0 0
> $axialCurveTag 1
>
> #Shear Spring Parameters
> limitCurve Shear $shearCurveTag $zeroLengthElement $rhos $fc $BCol $HCol $dt [expr
> $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $kf $Vr 2 0 1 3 1 2 0.0
> uniaxialMaterial LimitState $ColMatTagShear $Vcr $dcr $Vu $du $Vu $du [expr -$Vcr]
> [expr -$dcr] [expr -$Vu] [expr -$du] [expr -$Vu] [expr -$du] 0 0 $damage1 $damage2
> $beta $shearCurveTag 2 0
>
> #Rotation spring
> limitCurve Axial $flexureCurveTag $zeroLengthElement [expr
> $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $ka $Pr 1 0 1 3 6 5 0 0
> uniaxialMaterial LimitState $ColMatTagFlex $Mcr $Mdcr $My $Mdy $Mu $Mdu [expr -$Mcr]
> [expr -$Mdcr] [expr -$My] [expr -$Mdy] [expr -$Mu] [expr -$Mdu] $pinchX $pinchY 0 0 0
> $flexureCurveTag 1;
>
> section Elastic $ColSecTag $Ec $ACol $IzCol;
> section Aggregator $ColSecTag2 $ColMatTagAxial P
>
> #Elements - node is 1-3 (zerolength) then 3-2 beamwithhinge (with axial spring)
> element beamWithHinges $nonlinearbeamcolumn 3 2 $ColSecTag2 $Lpi $ColSecTag 0 $Ec
> $ACol $IzCol $ColTransfTag;
> element zeroLength $zeroLengthElement 1 3 -mat $ColMatTagAxial $ColMatTagShear
> $ColMatTagFlex -dir 3 1 6;


Hi , can you explain me how to calculate Kdeg or kf in "limitCurve Shear $shearCurveTag $zeroLengthElement $rhos $fc $BCol $HCol $dt [expr
> $rhos*$fyt*$HCol*$BCol*$dt*(1/$s)] $kf $Vr 2 0 1 3 1 2 0.0".
it would be very helpful to me. Thanks in advance.

[aylsworth]

You can use this document for that

http://opensees.berkeley.edu/wiki/index ... CE2004.pdf

[venkateshyadav]

aylsworth wrote:
> You can use this document for that
>
> http://opensees.berkeley.edu/wiki/index ... CE2004.pdf

Thank you
After using these below commands, do I have to still use the section Aggregator?
node 1 0.0 0.0
node 2 0.0 $LColumn
node 74 0.0 $LColumn

element forceBeamColumn 111 1 2 $np $ColSecTagEx $IDColTransf;
element zeroLength 112 2 74 -mat $ColMatTagShear -dir 2;
equalDOF 2 74 1 3;

limitCurve Shear $shearCurveTag $zeroLengthElement $rhos $fc $BCol $HCol $dt $Fsw $Kdeg $Fres 2 0 1 2 1 2 0.0

uniaxialMaterial LimitState $ColMatTagShear $Vi1 [expr $Vi1/$rigidSlope] $Vi2 [expr $Vi2/$rigidSlope] $Vi3 [expr $Vi3/$rigidSlope] [expr -$Vi1] [expr -$Vi1/$rigidSlope] [expr -$Vi2] [expr -$Vi2/$rigidSlope] [expr -$Vi3] [expr -$Vi3/$rigidSlope] $pinchX $pinchY $damage1 $damage2 $beta $shearCurveTag 2 0

Can you check whether my code is correct? And also in limitCurve Shear, inreger nodetag do I have to use the forceBEamColumn element nodes or zerlength element nodes?
Can you please clarify this?

[aylsworth]

No need for section aggregator if you just used zerolength element to assign the shear springs

You can use both. This might help you.

http://opensees.berkeley.edu/wiki/image ... Manual.pdf

[venkateshyadav]

aylsworth wrote:
> No need for section aggregator if you just used zerolength element to
> assign the shear springs
>
> You can use both. This might help you.
>
> http://opensees.berkeley.edu/wiki/image ... Manual.pdf

Thank you for your reply. I had already gone through this manual. In that manual it is given as below.
$ndI integer node tag for the first associated node (normally node I of $eleTag beam-column element)
$ndJ integer node tag for the second associated node (normally node J of $eleTag beam-column element)
But in the code you had presented in earlier posts, you used $ndI and $ndJ as zerolength element nodes. As per the above commands, one has to use beamcolumn element nodes isnt it? I have doubt in this.
Can you please clarify this? Thanks