problem with using FRP

04-Unexpected behaviour/errors
mai sayed
Posts: 3
Joined: 10 Nov 2018, 18:46

problem with using FRP

Post by mai sayed »

hello there

I'm studying something related to the use of FRP as a retrofit technique, but there is no effect while using it or not. and of course this not logical !!
i've tried it on a concrete shear walls and on a simple model of a column. if you removed the FRP nothing will change.
so those are my models and i wish to get an answer.
i'm using pushover analysis in the models.

https://drive.google.com/open?id=1eOqFZ ... fSQ2K_BvSM

thanx..
huffte
Posts: 978
Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
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Re: problem with using FRP

Post by huffte »

Hi mai sayed. I cannot seem to replicate your results, even with your model. I ran your concrete column model with and without FRP wrapping on elements 1 nd 4. The results are very different in the two executions. I haven't fully studied your model to understand it. But the FRP wrap does seem to be having a significant effect.
Tim Huff
mai sayed
Posts: 3
Joined: 10 Nov 2018, 18:46

Re: problem with using FRP

Post by mai sayed »

hi huffte.First I thank you for taking a look to my problem . but i need to know what exactly the significant effect that happen ?? because i didn't see any change in the pushover curve and that what it matters to me in my study.it seems to that neither the base shear or the displacement changes .
huffte
Posts: 978
Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
Contact:

Re: problem with using FRP

Post by huffte »

If you will plot global x-direction displacement versus load factor you will see very different results with and without the FRP wrapping. Again, I haven't looked over it meticulously, but I have trouble understanding your model. You seem to have 'top-beam' elements at the top and bottom of the cantilever, constructed of rectangular cross sections with no FRP. In the one case you have columns with FRP, in the other case columns without FRP, immediately adjacent to the top and bottom beams. The beams appear to undergo some inelastic behavior during the push. The beam elements are extremely short (cross sectional dimensions equal or exceed element length), which can prove problematic for force-based elements. So it is not clear to me what is the intended goal of the model. So, while I cannot attest to the validity of the model (that is up to you and your supervisor), I believe if you examine said curves, you will see that the FRP wrap is making a difference in the results. Best of luck with your work mai sayed.
Tim Huff
mai sayed
Posts: 3
Joined: 10 Nov 2018, 18:46

Re: problem with using FRP

Post by mai sayed »

i couldn't get what you mean by "plot global x-direction displacement versus load factor" , if you don't mind can you show me how, by steps ?
and you can ignore this model and take a look at my main model "A0F-1", i was just trying to figure out what i'm doing wrong in defining the FRP so i made that simple column model nothing more.
i really appreciate your effort with me.
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seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: problem with using FRP

Post by seismosoft »

Although we have not seen your model, note that the effect of FRP wraps on the column is increased shear capacity and improved confinement, which however does not alter significantly the member response. If you are not getting a very different behavior with and without the FRP wrap (until the shear capacity at least), this is not unreasonable.
Seismosoft Support
sg05025
Posts: 4
Joined: 02 Jan 2020, 13:13

Re: problem with using FRP

Post by sg05025 »

Hello
I am getting same results like without FRP and with FRP.( RC Rectangular Section and Dynamic time-history analysis)
If anybody could help, I would greatly appreciate you.
Thanks
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seismosoft
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Joined: 06 Jul 2007, 04:55

Re: problem with using FRP

Post by seismosoft »

The application of FRP wrapping on a RC section does not significantly affect its response, since it only provides confinement, shear and deformation capacity. In other words, the response might be the same (to be more precise, almost the same) however the member can sustain larger shear forces and larger lateral deformations.
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sg05025
Posts: 4
Joined: 02 Jan 2020, 13:13

Re: problem with using FRP

Post by sg05025 »

How do I edit frp wrap (with effect)
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seismosoft
Posts: 1184
Joined: 06 Jul 2007, 04:55

Re: problem with using FRP

Post by seismosoft »

If you are working on the SeismoStruct main window, you need to edit the corresponding section. Inside the Building Modeller this is done from the Member's Properties window on the left.
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