Unbonded prestressing condition

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AntoMarinelli
Posts: 43
Joined: Thu Aug 05, 2021 8:53 am

Unbonded prestressing condition

Post by AntoMarinelli » Fri Nov 05, 2021 10:36 am

Dear STKO,
I have to model an unbonded cable. My idea is to constrais the inital point of the bar to the concrete body by means of an "node to element" interaction and a "edof" constrains, but the analysis doesn't run because it says that the matrix is singural. I have also to precise that the bar is composed by a part that is bonded (for that I used an embedded condition) and a part unbonded, represented by a wire which each part has differents proprieties (in particular different different areas to simulate the ancorage lenght). How can I give the unbonded condition?

Thanks for the support
Antonella

marafini.f
Posts: 350
Joined: Fri Nov 13, 2020 1:52 pm

Re: Unbonded prestressing condition

Post by marafini.f » Tue Nov 09, 2021 7:07 am

Could you attach your model?

AntoMarinelli
Posts: 43
Joined: Thu Aug 05, 2021 8:53 am

Re: Unbonded prestressing condition

Post by AntoMarinelli » Tue Nov 09, 2021 9:09 am

Yes, sure!

Thanks in advance
Antonella
Attachments
UMI5_Elast_1layer.rar
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marafini.f
Posts: 350
Joined: Fri Nov 13, 2020 1:52 pm

Re: Unbonded prestressing condition

Post by marafini.f » Wed Nov 10, 2021 1:40 pm

Dear Antonella,
the singularity occurs because you are using a truss element and discretize it. The node of the bar that is created by the mesh and are not on the extremities are free, so your model is singular. You can try using a beam element, if you accept that something other then axial force is transmitted in such cable, otherwise you should discretize it as one single element and you analysis will run.
Francesca

AntoMarinelli
Posts: 43
Joined: Thu Aug 05, 2021 8:53 am

Re: Unbonded prestressing condition

Post by AntoMarinelli » Wed Nov 10, 2021 6:28 pm

marafini.f wrote:
Wed Nov 10, 2021 1:40 pm
Dear Antonella,
the singularity occurs because you are using a truss element and discretize it. The node of the bar that is created by the mesh and are not on the extremities are free, so your model is singular.



You can try using a beam element, if you accept that something other then axial force is transmitted in such cable, otherwise you should discretize it as one single element and you analysis will run.
Francesca
[what do you mean with a sigle element?]

marafini.f
Posts: 350
Joined: Fri Nov 13, 2020 1:52 pm

Re: Unbonded prestressing condition

Post by marafini.f » Thu Nov 11, 2021 8:32 am

Like this
UMI5_Elast_1layer_edits.rar
(242.33 KiB) Downloaded 27 times

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