WRC 107 Load Combination 1

[marchieV]

Dear All,

I just want to know what load combination should I use for the input tab of Loads in "WRC-107/297" analysis module of CAESAR II? Specifically for Expansion loads,should I use the load combination by considering the Sustain+Pressure (W+P1+T1) only OR just Temperature only (T1)?

Thank you in advance.

P.S.: See attachment for my concern.

Sincerely,

marchie

 

[TGS4]

The first option. And make sure that the stress limits for the membrane and membrane-plus-bending are done in accordance with the current guidance in VIII-2.

 

[jtseng123]

W+P1 is considered as Sustained load input, so it shall be T1. W+P1+T1 will be the total operating loads, not expansion loads.

 

[DSB123]

marchieV,
I bet you are confused now - two differing opinions being provided as answers!!

 

[TGS4]

There ought not to be any confusion. jtseng123 is completely incorrect, in the context of calculating the loads to be used in calculating the stresses in the SHELL of a pressure vessel due to piping restrained free thermal expansion loads.

See VIII-2 Table 5.6. (Although Table 5.6 of VIII-2 is not mandatory and only described example stress categorizations, the guidance provided therein constitutes the best knowledge in the industry). Not to mention that there have been multiple papers written on this topic (mine being one of many) that forms the basis of this guidance in the Code. For the piping, you can follow whatever guidance is provided in B31, but insofar as the vessel-proper is concerned, you must follow the guidance of the vessel Code - and even if it's VIII-1, U-2(g) would imply following the guidance in VIII-2.

BTW, it is also my opinion that almost every implementation of WRC 107/297 gets the categorization of the vessel shell stresses wrong (in an unconservative manner). Which is why I am in the process of re-writing the VIII-2 Part 5 elastic analysis rules, especially the stress categorization rules, hopefully in time for the 2019 Edition of VIII-2.