Guardrail Post Base Weld 1.5 Directional Strength Increase Factor 2

[cal91]

I have always used the 1.5 directional strength increase factor to calculate the moment capacity of my weld group from a guardrail post to it's baseplate.

For example, lets say the outside diameter of my pipe is 1.9" and I'm using a 3/16" weld all around.

Mu = 1.6*200LB*42" = 13.44 K-IN

Sx of weld group = pi * (D=1.9")^2 * (t=3/16") / 4 = 0.532 in3

LRFD Moment capacity of weld group = 1.5*22.27*0.532 = 17.8 K-IN (OKAY)

However, I came across this article that has me worried about using the 1.5 factor. I wanted to know if anyone else had heard of this.

https://steeltubeinstitute.org/hss/...15-design-of-fillet-welds-to-rectangular-hss/

 

[JAE]

It appears to have to do with the eccentricity of the fillet weld for one-sided welds on the sides of HSS tube walls
per the figure they provided:

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[cal91]

So JAE, are you saying you agree and that the 1.5 factor should not be used in this application?

 

[JAE]

From the overall impression I get from the article, I would be reluctant to use it.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[JAE]

I might add that we rarely use it in most cases, even with a pure 90 deg. application on a plate.
Usually go to it only if we really need to.

Check out Eng-Tips Forum's Policies here:
faq731-376