Modeling of line releases in RFEM 6

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1

Hi,

I’m relatively new to RFEM 6 and need some help with line releases.

I have HEB 260 beams supporting a 220 mm concrete slab. I want the concrete slab to distribute the loads to the HEB 260 beams, but I do not want the slab and beams to act as a composite structure.

In the model on the left, I have applied line releases using the conditions shown. In the model on the right, I have not used any line releases. However, both models produce the same maximum bending moment.

How should I model this correctly in RFEM 6 so that the slab transfers the loads to the beams without creating composite structure?

Thanks in advance!

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3

Hi Hannesny,

welcome to the Community!

To analyse the problem more precisely, the model file would be very helpful:

:right_arrow: Click on File → Save as and choose the following settings to reduce the file size:

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:right_arrow: Then upload the file here (e.g. *.rf6, *.rs9) – this way, the community can also contribute to the solution.

:owl: Prefer not to share the file publicly? No problem – send it to me via direct message: click on my profile picture or user name → Message.

Best regards
Stefan Hoffmann

4

Here comes the file :slight_smile:

Line release.rf6 (1.3 MB)

5

Hi Hannesny,

thanks for the model.

I would move my objects the their "origin" and link them with rigid links and a line hinge. This should be an appropriate model for such a situation, but I am not sure, if this will fit for you:

https://www.dlubal.com/en/downloads-and-information/documents/online-manuals/rfem-6/000082

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Line release_mod.rf6 (2,7 MB)

Best regards
Stefan Hoffmann

6

Thank you very much!

I think I understand how the forces are transferred. However, why is the spring stiffness k=1 assigned to the translational degrees of freedom ux and uz, as well as to the rotational degree of freedom?

7

Hi Hannesny,

thanks for your response following up my model.

If you release/ split objects, every split part of the model has to be numerically stable. As the line hing is the only "support" for the surface, I added a very small spring, which will most likely not take any force but stabilize the object for numerical reasons.

If you would release e.g. u_x completely, the surface is not supported in this direction.

Best regards
Stefan Hoffmann

8

Thanks for your help with modelling and explaining :slight_smile: