#8624 - 11/17/06 11:49 PM
B31.4 Allowable stress / Vertical pipes
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Member
Registered: 11/17/06
Posts: 5
Loc: Egypt
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Hi,
I'm using CAESAR II 4.5. Upon selecting B31.4, no allowable stress values appear. Any idea why??
Also, If I'm modeling a 50 meters vertical pipe (clossed loop chilled water system)and I specified a pressure of 15 Bars at the bottom, Will CAESAR II "feel" the difference in pressure at the top??
Best Regards,
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#8627 - 11/18/06 08:14 AM
Re: B31.4 Allowable stress / Vertical pipes
[Re: Hazem]
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Member
Registered: 12/13/99
Posts: 6226
Loc: Houston, Texas, USA
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With regards to B31.4, check the Code equations in the CAESAR II Quick Reference Guide. Based on the load case type (OPE, SUS, EXP, OCC), and whether the pipe element is in tension or compresssion, the B31.4 doesn't define an allowable for certain conditions.
With regard to the pressure head - "no". The pressure in the pipe is the pressure you specify on the spreadsheet.
Edited by Richard Ay (11/18/06 08:15 AM)
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Regards, Richard Ay - Consultant
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#30308 - 09/30/09 12:36 PM
Re: B31.4 Allowable stress / Vertical pipes
[Re: Richard Ay]
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Member
Registered: 02/04/08
Posts: 9
Loc: Buenos Aires - Argentina
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Iīm facing the same problem. Im analazing a scraper trap line, so, i have unrestrained (above ground) lines and restrined lines (buried with soil restraints modeled). In may opinion in this conditions there would be allowable stresses, but there isnīt. Wich would be the cause?
Regards.
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#39758 - 12/26/10 09:52 AM
Re: B31.4 Allowable stress / Vertical pipes
[Re: dlorenzoc]
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Member
Registered: 06/06/09
Posts: 128
Loc: Australia
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Dear Mr.Richard,
In caesar input spreadsheet, to define the ASME B31.4 Code allowable stress, there is an provision to enter it. My clarification is that do we have to enter the value of Sy or SMYS in that option.
Since as per ASME B31.4, the allowable stress is calculated as
Sy = F*E*SMYS
I am confused with the sentence provided in the help option, please clarify it...
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#39768 - 12/27/10 09:43 AM
Re: B31.4 Allowable stress / Vertical pipes
[Re: sillyman]
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Member
Registered: 12/13/99
Posts: 6226
Loc: Houston, Texas, USA
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You should enter SMYS.
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Regards, Richard Ay - Consultant
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#39769 - 12/27/10 10:34 AM
Re: B31.4 Allowable stress / Vertical pipes
[Re: Richard Ay]
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Member
Registered: 06/06/09
Posts: 128
Loc: Australia
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Dear Mr. Richard,
Thanks for your reply, and one more doubt is how the design factor F shall be considered in allowable stress, if we have two different F values...
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#40409 - 01/24/11 12:51 PM
Re: B31.4 Allowable stress / Vertical pipes
[Re: sillyman]
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Member
Registered: 06/06/09
Posts: 128
Loc: Australia
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Dear Richard,
I am waiting for your reply... Please response for it...
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#40413 - 01/24/11 02:13 PM
Re: B31.4 Allowable stress / Vertical pipes
[Re: sillyman]
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Member
Registered: 12/14/99
Posts: 2382
Loc: Houston, TX, USA
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The F in CAESAR II is only used (as F1) in Chapter IX. If you want, you can change this on each pipe element.
Where do you find this Sy = F*E*SMYS in B31.4. It appears to me that all allowable stress limits reference SMYS and not an Sy.
_________________________
Dave Diehl
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#40513 - 01/27/11 02:19 PM
Re: B31.4 Allowable stress / Vertical pipes
[Re: Dave Diehl]
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Member
Registered: 06/06/09
Posts: 128
Loc: Australia
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Dear DaveDiehl,
It is given in ASME B31.4, Section 402.3 - Allowable Stress and other stress limits....
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