#21871 - 10/27/08 07:40 PM
How to inform loading data for LNG rundown line
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Member
Registered: 08/15/06
Posts: 26
Loc: Korea
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Hello!
Regarding above subject, I just wonder which force between Restraint summary and Global element force shall be aplied for loading data in LNG terminal plant. In normal operating case, the Rstraint summary is correct but when LNG is flowing into the large pipe slowly, the Global element force is more conservative i.e. at anachor point, friction force is counterbalanced from each side for Restrain summary but, friction force is considered either larger one of them, upstream and downstream for Global element force
I would like that someone verify the above approach and advise me whcih loading data I have to consider.
Best regards,
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D.H.SEOK
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#21885 - 10/28/08 05:56 AM
Re: How to inform loading data for LNG rundown line
[Re: D.H.Seok]
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Member
Registered: 04/02/08
Posts: 231
Loc: Jakarta, Indonesia
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For your related nodes only, could you please paste the elements run input (input echo) and output values of both restraint & global elements forces reports to your next reply ? Thx...
Edited by Samsul P. Manik (10/28/08 06:09 AM)
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Many thanks & regards, Sam Manik
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#21956 - 10/29/08 07:55 PM
Re: How to inform loading data for LNG rundown line
[Re: Sam Manik]
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Member
Registered: 08/15/06
Posts: 26
Loc: Korea
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Ok! Here, attached file will help your understanding.
please check load for node 530 and then, advise me.
Best regards,
Attachments
461-ComparableLoadTable.pdf (427 downloads)462-ComparableLoadingData.doc (668 downloads)
Edited by D.H.Seok (10/29/08 07:58 PM)
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D.H.SEOK
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#21957 - 10/29/08 08:28 PM
Re: How to inform loading data for LNG rundown line
[Re: D.H.Seok]
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Member
Registered: 06/23/07
Posts: 285
Loc: Manila, Philippines
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Hi Seok,
select the maximum load condition and print the global force.. For Pipe rack this should be enough for the loading data.. vertical force are in standard support span and the loading guy know how to make one so, it is only necessary to print horizontal force. also try to evaluate your support load and some special cases. and for other structure, support function(ex. +y, stopper etc.) load only necessary meaning that the effect of transient load due to friction can be neglected... Also you can verify the loading contract from structural/loading(im not sure which but they have) for more detail. As every project has its own requirements,.
Regards!
_________________________
BOM
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#21966 - 10/30/08 04:05 AM
Re: How to inform loading data for LNG rundown line
[Re: bom]
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Member
Registered: 04/02/08
Posts: 231
Loc: Jakarta, Indonesia
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Dear Seok, Please refer to: c2quick.pdf >> Chapter 6 Technical Discussions >> Local Coordinates (x, y, z). Think how is the relation to the global coordinate (X,Y,Z) Please note that the resultan forces at pipe node 530 in two row report transfered to the support. Use newton law III, action = - reaction. The result is OK
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Many thanks & regards, Sam Manik
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#21968 - 10/30/08 05:19 AM
Re: How to inform loading data for LNG rundown line
[Re: Sam Manik]
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Member
Registered: 04/02/08
Posts: 231
Loc: Jakarta, Indonesia
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I forgot to attach this one. Please ignore my sign (+) or (-) if it is not correct. Quick count. Or I did not get it?
Attachments
463-Restraint-GlobalForce-LocalForce.pdf (407 downloads)
_________________________
Many thanks & regards, Sam Manik
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#22179 - 11/06/08 06:07 AM
Re: How to inform loading data for LNG rundown line
[Re: Sam Manik]
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Member
Registered: 08/15/06
Posts: 26
Loc: Korea
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Thanks to reply. but there are some misunderstanding between what I try to explain somthing and response. Anyway I explain one more. When we inform loading data for Anchor force, which load shall we give either restraint summary or global force? Restraint summary is shown that upstream and downstream loads are counterbalanced, however Gbobal load is shown that upstream and downstream loads are described each other. Someone says that the greater load between upstream and downstream load at the same node point for global load shall be applied in the intermediate anchor because of "it is possible that the pipe line may heat up gradually from one end. of the pipe sections to expand before the other. It is, therefore, considered good practice to design the intermediate anchor to resist the forces extered by one of two pipe sections" as described in EJMA para. B-2.4.1.1. Is is correct? I have never used and applied global load for loading inform until now. How about you......?
I hope that someone who have good experience advise me.....
Best regards,
_________________________
D.H.SEOK
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#22189 - 11/06/08 09:03 AM
Re: How to inform loading data for LNG rundown line
[Re: D.H.Seok]
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Member
Registered: 12/14/99
Posts: 2382
Loc: Houston, TX, USA
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The CAESAR II restraint report lists the loads ON the RESTRAINT - use these numbers to size/evaluate the support.
The Global Forces and Moments report lists the loads on the PIPE. The report is structured to illustrate the loads acting on each element in the piping system. That's why you see 10-20, 20-30, etc. This is a step towards calculating pipe stress.
You point out an interesting concern at startup (one side of an anchor gets hot before the other). I will not say whether or not it is significant but I will say CAESAR II knows noting about it (unless that's the way you set up your input).
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Dave Diehl
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