Connect zerolength element using rigid link element

[Jeena]

Hi all,

I have a two story shear wall model, where each shear wall is represented using zerolength element. The complete shear wall material property is assigned to the zerolength element.....

Which is the best way to connect these two zerolength elements ? Is "rigidLink beam " a good option ??

[fmk]

Jeena,

is this an ndm 1 ndf 1 problem? if so they are just connected through the nodes .. you need no other constraints.

if not, why not .. are you modeling other parts of the structure? ...

frank

[Jeena]

Hi,

This is my model data for a two story shear wall model...


model BasicBuilder -ndm 2 -ndf 3

## Nodes
node 1 0.0 0.0
node 2 0.0 120.0
node 3 0.0 120.0
node 4 0.0 240.0
node 5 0.0 240.0

## Mass
mass 3 0.2122 0 0
mass 5 0.1061 0 0

#Boundary Conditions
fix 1 1 1 1
fix 2 1 1 1
fix 3 0 1 1
fix 4 1 1 1
fix 5 0 1 1

#uniaxialMaterial SAWS 1 $F0 $FI $DU $S0 $R1 $R2 $R3 $R4 $alph $bet
uniaxialMaterial SAWS 1 41.7357 5.7576 3.2600 73.4250 0.0408 -0.0831 1.0100 0.0169 0.7392 1.1322
uniaxialMaterial SAWS 2 21.1164 2.9082 2.9900 50.3094 0.0419 -0.0598 1.0100 0.0160 0.7110 1.1653
uniaxialMaterial Elastic 3 1e10

## Transformation
geomTransf Linear 1

## Define Model

#element zeroLength 1 1 2 -mat 1 2 -dir 1 2
element zeroLength 1 2 3 -mat 1 3 -dir 1 2 -doRayleigh 1
element zeroLength 2 4 5 -mat 2 3 -dir 1 2 -doRayleigh 1
rigidLink beam 1 2
rigidLink beam 3 4

#--------------------------------------------------------------------------------------------------------------

So this a two story timber shear wall with each wall height is 120". If I don't connect the zerolength elements with rigidLink beams or any elements, the time period is less than expected ...

[fmk]

Jeena,

you might have 5 nodes and 15dof but most are fixed.

from your model you have the simple classic shear building model .. there is a much simpler way to model this (actually the nodes can have same crds as you are using zeroLength elements):

model Basic -ndm 1 -ndf 1
node 1 0.
node 2 120. -mass 0.2122
node 3 240. -mass 0.1061
fix 1 1

#uniaxialMaterial SAWS 1 $F0 $FI $DU $S0 $R1 $R2 $R3 $R4 $alph $bet
uniaxialMaterial SAWS 1 41.7357 5.7576 3.2600 73.4250 0.0408 -0.0831 1.0100 0.0169 0.7392 1.1322
uniaxialMaterial SAWS 2 21.1164 2.9082 2.9900 50.3094 0.0419 -0.0598 1.0100 0.0160 0.7110 1.1653

#element zeroLength 1 1 2 -mat 1 2 -dir 1 2
element zeroLength 1 1 2 -mat 1 -dir 1 -doRayleigh 1
element zeroLength 2 2 3 -mat 2 -dir 1 -doRayleigh 1
puts [eigen 1]

[Jeena]

Hi,

Thanks for checking my model.. I will try to run a new set of analysis using the modeling procedure u mentioned ...

[omaramin]

Hi Jeena,

I was wondering if it worked for you since I'm working on a similar issue.

Thanks!

[Jeena]

Hi,

My model is kind of working now and I am attaching a sample 2 story model. This is a simple shear model and doesn't include any axial flexural interactions. This is more less a single degree of freedom model per story level.

## Nodes
node 1 0.0 0.0
node 2 0.0 120.0
node 3 0.0 120.0
node 4 0.0 240.0
node 5 0.0 240.0


## Mass

mass 3 0.2122 0.00 0.00
mass 5 0.1061 0.00 0.00

#------------------------------------------------------------------------------------------------


#Boundary Conditions

# Fix the base node
fix 1 1 1 1
fix 2 0 1 1
fix 3 0 1 1
fix 4 0 1 1
fix 5 0 1 1

equalDOF 1 2 1;
equalDOF 3 4 1;

#------------------------------------------------------------------------------------------------

## Transformation
geomTransf Linear 1


## Materials

#uniaxialMaterial SAWS 1 $F0 $FI $DU $S0 $R1 $R2 $R3 $R4 $alph $bet
uniaxialMaterial SAWS 1 41.7357 5.7576 3.2600 73.4250 0.0408 -0.0831 1.0100 0.0169 0.7392 1.1322

uniaxialMaterial SAWS 2 21.1164 2.9082 2.9900 50.3094 0.0419 -0.0598 1.0100 0.0160 0.7110 1.1653
uniaxialMaterial Elastic 3 1e10

#-----------------------------------------------------------------------------------------------------

## Define Model

element zeroLength 1 2 3 -mat 1 3 -dir 1 2 -doRayleigh 1
element zeroLength 2 4 5 -mat 2 3 -dir 1 2 -doRayleigh 1

#--------------------


This is my model definitions and I was using this model to perform an Incremental Dynamic Analysis.

What is the problem u are working on ??? Let me know if you want to see the entire code for the IDA analysis or time history analysis.

[omaramin]

Hi Jeena,

Thanks for the reply!... For now I'm working on simple 2D shear wall models and want to perform pushover analysis. Initially I want to learn how to do multiple stories in 2D and then I might expand it to 3D. If you could attach the entire code for IDA and THA that will be great.
Also, I have a question regarding equalDOF command you're using in your model. So basically you're applying the constraint that DOF 1 for joint 2 should follow joint 1 but how can they be the same since joint 1 is the base and joint 2 is the second floor. Please have a look at Page 7 of this and let me know what you think.
http://opensees.berkeley.edu/wiki/image ... deling.pdf

Thanks,
Omar