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Active Member
georgimonew
Posts: 6
Registered: ‎04-09-2012

Load Cases / Envelope

1399 Views, 10 Replies
04-09-2012 11:41 AM

Hello!
I created 4 wind load cases and 3 snow load cases. My problem is to create an envelope containing wind cases and another containing snow ones. Is it possible? By doing this I want to reduce the number of combinations generated my Automatic combinations module. My teacher recommended this, too.
I read that robot cant create envelopes. Is it true?
Thanks in advance.

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Active Contributor
40ushek
Posts: 32
Registered: ‎12-26-2011

Re: Load Cases / Envelope

04-10-2012 12:41 AM in reply to: georgimonew

the goal - reduce the number of combinations generated my automatic combinations module?

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Active Member
georgimonew
Posts: 6
Registered: ‎04-09-2012

Re: Load Cases / Envelope

04-10-2012 05:40 AM in reply to: georgimonew

I was told its theoretically right to make a envelope combination - the Eurocode 1 says that. And the goal of course is reducing the number of combinations. It's a simple steel frame I don't need 200 combinations.
I've read the posts you told me but I see the only way is editing the load cases in excel? Grouping the combinations doesn't make a envelope of them, right?  Is there another way?
And if you don't understand me, I want to make a envelope as SAP2000 do it - it has a load combination type - envelope.

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Active Contributor
40ushek
Posts: 32
Registered: ‎12-26-2011

Re: Load Cases / Envelope

04-10-2012 05:56 AM in reply to: georgimonew
200 is very little. 1 000 000 combines is normal. I use for that special program (I author). I do it for myself.
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Product Support
Rafal.Gaweda
Posts: 5,587
Registered: ‎04-26-2010

Re: Load Cases / Envelope

04-10-2012 06:13 AM in reply to: georgimonew

 

And if you don't understand me, I want to make a envelope as SAP2000 do it - it has a load combination type - envelope.


I think we do not understand you. Also, at least me, do not know what is envelope case\ combination in SAP.

Envelopes are generated automatically in Robot these ways:

 

env1.jpg

 

env2.jpg

 

env3.jpg



Rafal Gaweda
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Active Member
georgimonew
Posts: 6
Registered: ‎04-09-2012

Re: Load Cases / Envelope

04-10-2012 06:28 AM in reply to: georgimonew

I want to create a envelope of 4 wind load cases and combine this envelope in ULS combinations, for example,
G+Q+0.5*envelope (Wind1; Wind2; Wind3; Wind4).
Thanks for the help. :smileyhappy:

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Product Support
Rafal.Gaweda
Posts: 5,587
Registered: ‎04-26-2010

Re: Load Cases / Envelope

04-10-2012 06:32 AM in reply to: georgimonew

I want to create a envelope of 4 wind load cases and combine this envelope in ULS combinations, for example,
G+Q+0.5*envelope (Wind1; Wind2; Wind3; Wind4).

And the result of the above is ...?

Tell me what you want to get. 

 

 

 



Rafal Gaweda
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Active Member
georgimonew
Posts: 6
Registered: ‎04-09-2012

Re: Load Cases / Envelope

04-10-2012 06:44 AM in reply to: georgimonew

Tihs is a combination. I want the maximum values of the internal forces. Instead of combining dead and live loads with 4 wind load cases to be just 1. I hope I gave the right answer.

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Product Support
Rafal.Gaweda
Posts: 5,587
Registered: ‎04-26-2010

Re: Load Cases / Envelope

04-10-2012 07:16 AM in reply to: georgimonew

Tihs is a combination. 


Not possible.



Rafal Gaweda
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