plastic hinge in pushover analysis

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arash1985us
Posts: 17
Joined: Wed Feb 25, 2009 7:48 am

plastic hinge in pushover analysis

Post by arash1985us » Wed Oct 07, 2009 12:43 am

Dear Dr. Silva:
How can I see where the plastic hinge are formed in 2D frame with fiber section and nonlinear beam-column element?

silvia
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Post by silvia » Wed Oct 07, 2009 6:45 am

if you want to watch it grow, you should use many displacement-based beam-column elements.
with the force-based nbc element, plasticity is forced at the integration point and the hinge length is equal to the integration-point weight.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104

arash1985us
Posts: 17
Joined: Wed Feb 25, 2009 7:48 am

Post by arash1985us » Wed Oct 07, 2009 12:25 pm

Thanks Dr.Silvia;
so, you mean:
1-I must use displacement-based nonlinear beam-column elements instead of forced-based ones in pushover?,and
2-how should I adjust the records?Should I record moments at each node of elements and compare with plastic moments to see where the plastic hinge are formed?

silvia
Posts: 3912
Joined: Tue Jan 11, 2005 7:44 am
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Post by silvia » Wed Oct 07, 2009 1:37 pm

it's up to you on how you define it.
Silvia Mazzoni, PhD
Structural Consultant
Degenkolb Engineers
235 Montgomery Street, Suite 500
San Francisco, CA. 94104

emanueletrainini
Posts: 5
Joined: Wed Nov 30, 2011 8:12 am

Re:

Post by emanueletrainini » Wed Nov 30, 2011 8:55 am

arash1985us wrote:
> Thanks Dr.Silvia;
> so, you mean:
> 1-I must use displacement-based nonlinear beam-column elements instead of
> forced-based ones in pushover?,and
> 2-how should I adjust the records?Should I record moments at each node of
> elements and compare with plastic moments to see where the plastic hinge
> are formed?

about (2). It can brings to some mistake IMHO. As you are in charge of setting moments lenght, it could result in a very low accurate evaluation. Isn't it?
Emanuele Trainini, architetto :: Brescia
Progettazione | Certificazione Energetica
Denunce di Successione | Pratiche catastali

esi_opensees
Posts: 93
Joined: Mon Apr 14, 2008 10:53 pm

Re: plastic hinge in pushover analysis

Post by esi_opensees » Fri Dec 09, 2011 7:43 am

I think you need to do a post-process step. You can use stressStrain as a argument of “recorder element”, draw the stress-strain curve, and see that material nonlinearity has been reached or not.
Any opinion?

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