Change material or section after analysis

[DKJung]

Hi,

I am interested in modeling of repair of a damaged reinforced concrete column. That is, once the RC column is damaged in the plastic hinge region (e.g. cover concrete spalling & rebar yielding) under the loading, the column is repaired with fresh concrete keeping the rebars the same. I guess it is not possible to do that in OpenSees, but is there any way to change partial concrete material only of the damaged elements (sections) in the RC column in OpenSees leaving the yielded rebars ?

I think the best I can to for the repair in current OpenSees is to replace the damaged portion with a new element. Is that right?

Thank you.

[Jhno]

This is just a thought but, wouldn't editing the values of the concrete inside and outside the confinement (assuming you used a fiber section) do the trick?

[fmk]

you cannot swap out or add fibers in an existing section in an element with current .exe (you could potentially modify the application to do so). just adding concrete fibers to another element and putting this in parallel with the existing one will potentially work if you are using the displcement based element and you keep the section symmetric.

[zfkrish]

I realize that this question was asked some time ago, but I am modeling something similar and am having difficulty working around this as well. I run an initial analysis on a column modeled with displacement based elements as you said. Once this is complete I then add new elements to represent the repair in parallel with the existing. The problem is that the repair elements are much stiffer and since the original model has residual deformation from the first analysis it seems that the repair elements are initiating at the force they would have if they were deformed to the same level of strain as the original elements. Is there any way to model this so that only the additional strain from the second analysis is considered in the new elements?

[fmk]

the new elements should subtract off any initial displacements (displacements at time element is added) from the current displacement .. you can test this by adding the element and w/o changing the load do an analysis step and check that new elements have 0 force (assuming you are in equipment and nodes do not move during next analysis)