My Code Stress Seems High

Hello,

I'm getting a 245.67% stress ratio (sustained case) at an intersection node, which seems a bit high. The intersection consists of a 4" sch40 pipe with a 1" sch80 pipe branch and I've set the "SIFS & Tees" on the intersection to "8 - Socket". Attached is a screen shot of the intersection in question, the stress table, global element forces extended report, and my attempt to calculate the stress with Excel.

What am I missing?

-Levi

There isn't enough info to tell. Please open a Support Request on Smart Support and send in your job file.

I might put in a support request at some point, but shouldn't I be able to find the sustained code stress with the moments and pipe dimensions?

Something like this:

[ft*lb] [in*lb]
Mx= 250.5 3006
My= -36.3 -435.6
Mz= 8.6 103.2

I/c[in^3.]= 0.1606
SIF= 1.3
Allowable Stress= 20000

Mr= 3039.150144 =SQRT((Mx)^2+(My)^2+(Mz)^2)

σ= 18923.72444 =Mr/(I/c)

σ*SIF= 24600.84177
Stress %= 123.0042088

Too many questions remain but I'll give it a try...

You are running B31.1, you have corrosion defined (about 0.08 inches), and you have all cases corroded?

I'm using B31.3 and my corrosion is set at... ohwwww... 0.125 in. That seems like it could be a bit of a problem, seeing as the wall thickness is only 0.179 in. I didn't think to set the corrosion and it just grabbed the value from a thicker pipe.

Well, I better add corrosion to my pre-run check list. Thank you.

-Levi

Yes! That fixed it. Thank you!