Hello,

I'm using the Caesar 2018 version and I cannot match the Code stress value that Caesar shows for the Occasional component.
The element that I'm checking is a welding reducing tee (42*18, th=0.625" and tb=0.375").
The local element forces for the occasional event gives the following moment in the junction (for the branch):
Mx=-19338.7 ft.lb
My= -16132.1 ft.lb
Mz= -3387.4 ft.lb
The resultant moment is= 25411 ft.lb.
ASME B31.1 states that the occasional term of the Code check is:

0.75*i*MB/Z (U.S. Customary Units)

i= 5.929 (per Caesar)
Z= 91.4 (per Caesar)
so the occasional term is 14835 lb/in^2.

The point is that Caesar calculates a number 1.333 times larger.
May Caesar use a different value of Z?
Any help appreciated.

Z effective is still used a will be phased out with B31J. See B31.1 section 104.8.4 and my quick calc came up with Z=152.5 in^3 which is 1.66 times larger than the 91.4 regular Z based on 18"x0.375".

There are some more options for the calc that may come into play here.

Hello Bob,

thanks for your reply. Yes, the effective Z is still used but a larger Z will give a smaller stress.

In the case I'm exposing it seems that Caesar uses a factor to increase the resultant moment MB, or reduces the Z.

We have a checkbox for B31.1 tees - "Meets D1, Notes 10a, c, d, e, f".
If it is checked, then your branch SIF is 5.929. If it is NOT checked, your branch SIF=4.364. That's close to the 1.33 that you are seeking.

But my output stress report shows the proper branch SIF. (The header SIF = 4.363 in either case.)

Hello Dave,

thanks for your reply. The checkbox is clicked and the output indicates a SIF=5.929.

In any case, a lower SIF would result in a lower code stress but in this case is the opposite, Caesar is calculating a larger code stress with the moments at the branch point I listed above.

The material I'm using is A515 Gr 55 with a Wc=0.8, but as far as I understand the Wc only reduces the allowable stress for the sustained case, does not affect to the Code stress value.

Jhero,

Could you file a Service Request on Smart Support(smartsupport1.intergraph.com/) for this issue?


Also, Please attach the CAESAR II file for illustration purposes(Either in Smart Support or Here).