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Generated Diaphram Nodes

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Stazz

Structural
Oct 22, 2008
100
Risa keeps telling me that the nodes that are generated for applying the wind and seismic forces are unstable even though they are in the horizontal plane of the diaphram. Apparently everytime you recalc the wind and seismic loads you also generate a new set of nodes (I beleive?). This makes sense because I have a whole mess of faded out nodes in my Joint Coordinates spreadsheet and my wind and seismic forces are still transfering to base reactions in my model. How do I get rid/delete these nodes. They are cluttering my model.
 
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Ok, first I didn't like these nodes because they simply cluttered my model. Now I despise these things because they won't let me run a dynamic analysis. I want these nodes combusted! Someone please help.

To sum up again, Risa generates new nodes to apply forces to every time I adjust my wind and seismic calculations leaving the old nodes still in the data but they aren't attached to anything leaving them unstable. How can I delete these nodes?
 
Stazz -

That shouldn't be possible.... RISAFloor should delete and re-generate the nodes used to generate wind and seismic loads everytime you re-enter the 3D / Lateral model.

The only exception that I can think of is if you have applied loads directly to those joints in RISA-3D. At that point, Floor doesn't want to delete those joints becasue they have RISA-3D specific data associated with them.

Even if the GUI (Graphical User Interface) doesn't let you delete those nodes (becasue they are flagged as a necessary part of the Floor model), there are still ways to get rid of them. If you e-mail your model into RISA's Technical Support group at support@risatech.com then we can take a look at it and see what the heck is happening here.
 
Hi Stazz,

Assuming you're just generating the joints in RISA-3D (not from RISAFloor) you can get rid of the generated joints by running the Wind or Seismic generators with the code set to None.

We've tested the generators in RISA-3D and we're not able to reproduce this behavior, would you send your model to our Support group and tell them what you were doing when the extraneous nodes started getting created.

Kind Regards,


RogerAtRISA
RISA Technologies
 
Hi again Staaz,

After more testing, I saw that with RISA-3D standalone, you will get protected joints when you generate the Seismic or Wind loads, but this protection goes away when you save and then reload a model. If you then create a new set of Seismic or Wind loads at a new location, it will not delete your old joints, but they aren't protected at that point and you can delete them.

We'll be making a change in the 8.0 update of RISA-3D to either make them consistently protected or not protected, not sure yet, we're still discussing it.

Give Support a call or email if you're still having any issues with this.



RogerAtRISA
RISA Technologies
 
Thanks guys! looks like the problem got resolved. Great help.

It comes down to a check box in the preferences...

Main Menu Toolbar (from within RISA-3D) select Tools-Preferences - Solutions and Results. The first check box on this screen says, "Lock isolated ROTATIONAL instabilities without notification?".
 
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