pushover analysis

02-Getting started with the modelling
Post Reply
Gonzalo
Posts: 19
Joined: 30 Jun 2011, 04:46

pushover analysis

Post by Gonzalo »

Hi,

I modeled a 3 story RC frame and I performed a static pushover analysis on my model. I have some problems with the output displacements. I can't find the displacement of nodes at the peak of base shear. for example if I define 1 meter for target displacement the roof displacement will obtain 1 meter. I don't khow what's the reason. please help me.
You can download my model from here:
http://www.mediafire.com/?kuv77b7jj92tghh

Best Regards.
Gonzalo.
fbianchi
Posts: 54
Joined: 29 Aug 2008, 04:02

Re: pushover analysis

Post by fbianchi »

Hi Gonzalo,

I downloaded your model and I checked it. First of all l noticed that you were applying 'displacement incremental loads' in conjunction with the 'response control' phase, and this is not correct. So, if you replace the 'displacement incremental loads' with the 'force incremental loads', and run the analysis, when the base shear is maximum the top node (n114) should displace of 0.32 m (more or less). Let me know if you can see this result.

Cheers,
Federica
Gonzalo
Posts: 19
Joined: 30 Jun 2011, 04:46

Re: pushover analysis

Post by Gonzalo »

Hi Dear Federica.
Thank you for your attention.

1.I used 'force Incremental loads' (with the same values) and my top node's (n114) displacement obtained 0.32 m.did you find any other mistakes in my model?
2.I want to use static pushover analysis with the 1st mode distribution.I performed an eigenvalue analysis on my model and I normalised the displacements of 1st mode.then I used this lateral load distribution in the type of 'force Incremental loads' as you said.Is my method correct for static pushover analysis using the 1st mode?
3.I want to perform force based and displacement based adaptive pushover analysis on my model too.which kind of applied loading and loading phases should I use for force based and displacement based adaptive pushover?

Thanks for your help.
Best Regards.
Gonzalo.
fbianchi
Posts: 54
Joined: 29 Aug 2008, 04:02

Re: pushover analysis

Post by fbianchi »

Hi Gonzalo,

1. Ok.
2. The lateral load distribution depends on the normalized mode shape (from the displacements obtained performing an eigenvalue analysis) and the story mass.
3. For a displacement-based adaptive pushover you have to apply "displacements" in the "Applied Loading" module in conjunction with an "Adaptive Load Control" as "Loading Phase". If you refer to the Help System of the program, and search for Bibliography, I'm sure that you can find further details on this topic..

Cheers,
Federica
Gonzalo
Posts: 19
Joined: 30 Jun 2011, 04:46

Re: pushover analysis

Post by Gonzalo »

Hi dear Federica,
Thanks for your response.

I read the Help System of the program severel times, but I can not still perform the force based and the displacement based adaptive pushover analysis on my model.I want to compare these two method results (the displacement of n114 at the max of base shear) with the static pushover analysis.for the DB adaptive pushover I applied 'displacement' in the 'applied loading' and 'adaptive load control' in the loading phase, the analysis completed but the roof displacement in the max of base shear didn't obtain in 'Post processor\Structrul displacement' (As my pushover analysis model that you downloaded).
please help me for FB adaptive pushover settings in the 'applied loading' and 'loading phases'.

Sorry if I ask many questions.I don't have any other reference to solve my problems.
thanks for your favour.
Gonzalo.
User avatar
seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: pushover analysis

Post by seismosoft »

Dear Gonzalo,

With the Wizard, you can readily create examples of DB adaptive pushover, hence we suggest you just follow one of such examples in order to learn how to run such type of analyses.

Then, in order to run the FB adaptive pushover (which in general performs poorly, by the way), just change the nominal loads from displacements to forces and the type of scaling from displacement-based to force-based.

Seismosoft Support
Gonzalo
Posts: 19
Joined: 30 Jun 2011, 04:46

Re: pushover analysis

Post by Gonzalo »

Hi,

When I select '2D RC frame' and 'adaptive pushover analysis' in the wizard window the analysis doesn't run!You can try it!
Which kind of loading phases do you suggest for FAP and DAP?

Best Regards.
Gonzalo.
User avatar
seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: pushover analysis

Post by seismosoft »

Yes, you are right, Gonzalo.

Go to the Eigenvalue settings and select the Lanczos algorithm. Things should work now.

We will correct this.

Seismosoft Support
Mina Rizkalla
Posts: 11
Joined: 27 Jul 2019, 16:18

Re: pushover analysis

Post by Mina Rizkalla »

Hey,
I performed a pushover analysis on a building but I have some troubles with the solution.

considering the deformed shape ..... it seems like the first story is only pushed while the other top stories are not.
considering the capacity curve .... the curve I get is so weird as it after goes up, it reverses its direction and goes down below the X-axis making negative values of base shear.

I used on diaphragm for each floor (the master node is the CG of the building, while all the other story nodes are slave nodes)
the applied loads ....are Incremental force loads .... the values are assigned in an inverse triangular form.
and only defined for the edge nodes not for the whole story nodes.
the loading phase .... is Response Control

could anyone please tell me what shall I revise or what mistakes are committed ?
User avatar
seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: pushover analysis

Post by seismosoft »

You may check the models with the wizard of thr Bulding Modeller, and how the response control pushover is applied. Also you can download and use the models from our models' database from:
https://seismosoft.com/seismobuild-seis ... le-models/
Seismosoft Support
Post Reply

Return to “02-Getting started with the modelling”