Pushover analysis

[amirkochek]

Dear friends,
I want to ask is it possible to do pushover analysis with displacement input instead of considering force or acceleration as input for loading of a structure. In other words, is it possible to consider displacement for loading of the structure instead of force as input for assessing forces can create due to displacement as output? Hope the best and merry charismas and happy New Year for all.

[vesna]

Yes, you can do it. Use sp command in a load pattern.

[amirkochek]

vesna wrote:
> Yes, you can do it. Use sp command in a load pattern.
Dear Vesna,
Thank you very much for kind attention and reply. That is very kind of you

[amirkochek]

amirkochek wrote:
> vesna wrote:
> > Yes, you can do it. Use sp command in a load pattern.
> Dear Vesna,
> Thank you very much for kind attention and reply. That is very kind of you
In Sp Command it is possible to consider single-point constraint and I want to consider a series of displacement for a node. In other word, I want to consider a series of displacement in a hysterisis cycle to a anode to gain to the forces which is mentioned in that hysterisis model. Is it possible to consider series of displace ment for a node for performing Pushover analysis.

[vesna]

You can do it by generating the file that will contain the displacement history you want to assign to a node. If the name of the file is displacementx.txt, create the time series like this:

set Historyx "Series -dt $dt -filePath displacementx.txt"

and then define the load pattern like this:

pattern Plain 10 $Historyx {
sp $nodeTag $dofTag $dofValue
}

[amirkochek]

vesna wrote:
> You can do it by generating the file that will contain the displacement
> history you want to assign to a node. If the name of the file is
> displacementx.txt, create the time series like this:
>
> set Historyx "Series -dt $dt -filePath displacementx.txt"
>
> and then define the load pattern like this:
>
> pattern Plain 10 $Historyx {
> sp $nodeTag $dofTag $dofValue
> }
Dear Vesna,
Your technical notation was reaaly helpful and helped me a lot. I was trying to do it by considering Displacement in groundmotion Command but it dosent seem to work and your note is much much better. Thanks alot.

[amirkochek]

amirkochek wrote:
> vesna wrote:
> > You can do it by generating the file that will contain the displacement
> > history you want to assign to a node. If the name of the file is
> > displacementx.txt, create the time series like this:
> >
> > set Historyx "Series -dt $dt -filePath displacementx.txt"
> >
> > and then define the load pattern like this:
> >
> > pattern Plain 10 $Historyx {
> > sp $nodeTag $dofTag $dofValue
> > }
> Dear Vesna,
> Your technical notation was reaaly helpful and helped me a lot. I was trying to do it
> by considering Displacement in groundmotion Command but it dosent seem to work and
> your note is much much better. Thanks alot.
I want to ask is it possible to utilize Static Reversed Cyclic command instead od normal pushover analysis? As my main purpose is considering displacement part of a hysterisis model for loading?

[vesna]

What is Static Reversed Cyclic command?

[amirkochek]

vesna wrote:
> What is Static Reversed Cyclic command?
Dear Vesna,
Here I have copid one part from opensees example manual about
Static Pushover
Two types
Monotonic Pushover: One-directional displacement-controlled static lateral loading
Reversed Cyclic Pushover:
One-directional displacement-controlled static lateral loading
Displacement cycles are imposed in positive and negative direction

[vesna]

Yes you can use Static Reversed Cyclic command to generate displacement file you need. Make sure to understand what the command does. Do not use it blindly.

[bmj]

Hi,
I want to analyze a RC frame one bay. I've done pushover analysis but I do not whether my model is correct or not. Actually, I've a few problems as follow:1.) I have written the parameter of analysis as in the example4 (static reversed cyclic) and I'm not very practical with these values so I don't know what I can change in order to enter my lateral loading program (history). 2.) I get the result but I'm look so stupid how to read it. So then, I cannot to plot the graph in order to see either my result can match with the experimental result. I'm new user for this program. I hope you can help me!!

[fmk]

you should probably have started with Example3 in the basic examples manual instead of jumping into the more advanced model. you want to plot displacements agains the lateral load.

http://opensees.berkeley.edu/wiki/index ... r_Analysis

in this example the node32.out file contains the displacements and pseudo time. to get lateral load for the example multiply the time by 2*H (the load being applied)

[bmj]

Thank you very much for kind attention and reply.

[bmj]

Hi fmk,

Sorry if I'm asking you very simple question. I tried to run the pushover analysis of Example 3 (without do any modification) but I received this warning "addNode-node with tag 1 already exist in model, WARNING failed to add node to the domain". Should I modify the node number in the model. Thank you.

[bmj]

hi fmk,

my problem solve. Thank you.