#### Topic: Internal Mesh Connectivity

Hello,

I´m using Atena 3D to model a reinforced beam. The concretes-structure-mesh is made out of structured hexahedral elements.
Now I have to get sure that the upper and lower reinforcement bars are NOT getting connected with the stirrups.
So I was modelling the concretes mesh in that way, that there is one hexahedral element between the reinforcement bars and the stirrups.
Now to may question.

I want to know, how the reinforcement notes (and also the macro joints of the reinforcement) in generel are connected to the surrounding hexahedral elements.
For example, how this connections from the reinforcement notes to the notes of the hexahedral elements are weighted.
Or if this connections could be shown in the program.

Hopefully someone could help me in this case.

Thanks!

#### Re: Internal Mesh Connectivity

Dear Max,
the element in between is not necessary. The bars would be connected only in case of sharing macro node.

Regarding the connection of bar nodes in hexahedra elements, when no bond is set to bar the position of the bar node is calculated as linear combination of hexahedra nodes.

If there is also the bond law then the inner iterative process starts and the slipping may occur.

You can also check the paper that presents this topic:
https://www.researchgate.net/publicatio … _with_bond

With best regards,
Michaela Vaitova

#### Re: Internal Mesh Connectivity

Dear Max, for the basic information related to connecting reinforcement to the surrounding elements, please see ATENA
Troubleshooting, 2.1.21 When I model the reinforcement, do the bars and stirrups have to be in geometric connection (with common intersection points) or they can be modeled according to their axis so that they do not touch one the other in geometric sense?

I understand you include the layer of volume elements between the longitudinal bar elements and the stirrups to avoid both being connected to the same nodes, even just with small weights. If that least to very small elements (possibly breaking the assumptions for concrete as continuum), it may be better to use bond law(s) for one or both of the reinforcements (as Michaela suggests). If you are interested primarily in other cracking than what can be captured as slip along the bar axes, please explain (see also Troubleshooting, 2.1.1).

Regards.