base plate fix support shell

[vanvan11]

hi all

sorry can someone tell me is it my model correct 

i try to model fix base plates with shells 

10X 

[Artur.Kosakowski · Accepted solution]

You may want to have a look at the bolt support definition and consider replacing UZ+ with UZ-. 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[vanvan11]

10x 

can you tell me why i have z reactions with "+" and "-" in different comb when node support is uplift +-z

[Artur.Kosakowski]

I'm not sure what you mean. If you have nodal supports with UZ+ you should have only  positive vertical reactions in these nodes. If UZ- only negative. 

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.

[vanvan11]

"If you have nodal supports with UZ+ you should have only  positive vertical reactions in these nodes "

YES! but the results are not only positive vertical reactions why is that .That is my issue

or i miss something

[Artur.Kosakowski]

Leaving aside seismic cases (the model with uplift is not suitable for modal analysis) this should be like you said provided the analysis converged. Is this true for all simple load cases and combinations with the exception of the ones that include seismic? 

[vanvan11]

yes 

thanks a lot
I understand now. support uplift is not used in seismic combinations because the results are approximate
So it must present seismic force as ordinary horizontal force and then I should be closer to the truth?

[Artur.Kosakowski]

Yes 

See also:

http://forums.autodesk.com/t5/robot-structural-analysis/uplift-elimination/m-p/3744231

If you find your post answered press the Accept as Solution button please. This will help other users to find solutions much faster. Thank you.