Posted by: Goodsalt
+Y Restraint Reports a Positive Load on the Restraint - 08/12/08 11:48 AM
I've defined a +Y restraint for a system which is fairly complex - it's jacketed with static seismic equivalent load cases with displacements at various restraint locations (CNoded of course) to simulate building drift. CEASAR is reporting for at least one of the load cases a positive load (7006 lb.)on a restraint defined as +Y. This seems wrong. Is it?
Posted by: Richard Ay
Re: +Y Restraint Reports a Positive Load on the Restraint - 08/12/08 12:08 PM
Your looking at a "difference" load case.
Posted by: Goodsalt
Re: +Y Restraint Reports a Positive Load on the Restraint - 08/12/08 01:13 PM
I guess I'm having trouble figuring out if this is a "real" load or not - by which I mean is it a load that the restraint will actually "see" and for which it needs to be designed?
Posted by: Richard Ay
Re: +Y Restraint Reports a Positive Load on the Restraint - 08/12/08 01:17 PM
What is the load case you're looking at? Is it something like:
"W + P1 + T1", or is it something like:
"L3 - L5" ?
Posted by: Goodsalt
Re: +Y Restraint Reports a Positive Load on the Restraint - 08/12/08 01:38 PM
It's L1 + L11 where L1 = W+T1+P1. L11 is itself a combination of other load cases:
L11 = L7+L9
L7 = L3-L1
L3 = W+T1+P1+D1
L9 = L5-L1
L5 = W+T1+P1+U1
Posted by: Richard Ay
Re: +Y Restraint Reports a Positive Load on the Restraint - 08/12/08 01:45 PM
For your cases 3 and 5, you're looking at real loads on the restraints (because these are basic load cases). For cases 7 and 9 you're looking at restraint differences between two states (these are combination load cases).
For case 11, you have the sum of two differences (a combination of combination cases). Now you want to add this to a basic load case ...
I suggest you send your job to techsupport@coade.com and explain your rational for setting up these load cases.
Posted by: shr
Re: +Y Restraint Reports a Positive Load on the Restraint - 08/12/08 07:50 PM
There could be one case when +Y support also show positive load.
If guide or limit stop is used in same location & co efficient of friction value is also use for guide or limit stop support.
If say pipe will lift up same time it show positive frictional load.
Posted by: Sam Manik
Re: +Y Restraint Reports a Positive Load on the Restraint - 08/12/08 11:35 PM
Below are also the related links:
http://www.coade.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=19022&page=3#Post19022http://www.coade.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=18899&page=4#Post18899-----------------------------------------------------------------------------------
"ONLY stress as the Output Type for your combination load cases (this include EXP as well).
Displacements, Forces and Moments are NOT REAL in combination load cases"
-----------------------------------------------------------------------------------
Posted by: Clayton
Re: +Y Restraint Reports a Positive Load on the Restraint - 01/17/12 08:42 AM
What is the utility of Caesar generating a support force report for a fictitious load? Is there a situation in which you would look to the difference load cases for support forces?
Posted by: Dave Diehl
Re: +Y Restraint Reports a Positive Load on the Restraint - 01/17/12 10:41 AM
C2 shows the change in the support load for the difference case you have selected. Is that useful? Not to me. There are many reports that I do not view. Things get sticky though if you suggest that we should categorically eliminate certain reports.
Posted by: danb
Re: +Y Restraint Reports a Positive Load on the Restraint - 01/19/12 02:29 PM
Sometimes is usefull to pass this kind of net loads to structural/civill department. They have different approach then piping/stress department.
Regards,