Slab reinforcement

[Anonymous]

Hi!

I am trying to reinforce a slab and i keep getting the following error message:

"Required types are not ascribed to sls combinations. Automatic combinations were used in calculations as quasi permanent combinations".

Am i free to ignore this message? In norwegian standards we sometimes use SLS:FREQ for checking cracks. So my question is whether or not robot calculates cracks according to the loads i have defined in the SLS box even though they are defined as SLS:FREQ and not SLS:QPR, or will robot try to create its own combinations with new load factors?

[Artur.Kosakowski]

Hi @Anonymous

Check this article.

If I managed to answer your question(s) press the Accept as Solution button please. This will help other users to find solution(s) much faster. Thank you.

[Anonymous]

Hi, have tried that, but i stil get the same error message. I have moving loads in my manual combinations and every time i run calculations robot creates 3 additonal load cases. Two of them with + and - i in the name i understand, but the third seems to be a copy of the old combination. The old one does not genarate any forces in the slab, while the one robot creates randomly generate forces but is not reconginzed as a SLS:QPR combination. I have researched this and from what i could tell according to this forum post that i found it seems to be bug https://forums.autodesk.com/t5/robot-structural-analysis-forum/bug-in-load-case-list/td-p/4419865. As a recap to me the problem seems to be that the new combination that robot randomly creates is not recongnized as a SLS:QPR combination, while the original one does not create any froces and thereby no reinforcement.

[Artur.Kosakowski]

Hi @Anonymous

If you created  a combination with a moving load this is how the program works.                                                            

[Anonymous]

Thanks for your help Arthur!

So if i understand you correctly i should not ignore the message but rather create a SLS:QPR combination that dosent have any moving loads?

[Artur.Kosakowski]

Hi @Anonymous

Assuming that you want to include the moving load in the design you shouldn't exclude it.  Could you attach the model and describe the steps to follow to reproduce this situation?

[Anonymous]

Here you go 

https://swecogroup-my.sharepoint.com/personal/valon_hyseni_sweco_no/_layouts/15/guestaccess.aspx?doc...

I uploaded it as a onedrive link because of size 

It is a plate resting on soil springs. I have created manual combinations with load case 34 and 35. They disapear from the drop down meny after the calculations but they can be viewed in the combinations table. After the calculations robot makes copies of those combinations and asigns them a  load case number of 100 and 103. When i try to to design for cracking of load case number 100 and 103 robot dosent recongnize those as SLS:QPR combinations and i get the aforementioned error. However when i try to check for cracks for load cases 34 and 35 which are the combinations i created i dont get any error message, but i dont get any reiforcement either since those load cases dont induce any stresses in the plate. 

[Artur.Kosakowski · Accepted solution]

Hi @Anonymous

I converted the positions of the vehicles from cases 296 and 27 into simple load cases and then I used them for creation of all types of SLS combinations. Finally I entered case 1 in the ULS list as you are not supposed to run reinforcement calculations for SLS only.

If I managed to answer your question(s) press the Accept as Solution button please. This will help other users to find solution(s) much faster. Thank you.

[Anonymous]

Thanks Arthur!

But i think users should have the option of overriding this error message in the future.