Gusset Plate Weld Check

[PEinVA]

Hi,
We have designed a building using ASD '89. As our office was still under IBC 2003 until this year. The detailer has submitted a gusset plate calculation using ASD from the 13th edition. Not really a big deal, but as I'm still teaching myself everything from the 13th edition, I'd like some help clarifying weld calculations.

The Weld Allowable Strength is given as:

(1/FS)Rn = Beta* 4 * (1/2) * 0.6 * Fexx * 0.707 * w * L.

I get the 1/FS part and from the 0.6 on. The Beta I tracked down in the specifications. I cannot locate the 4 and/or 1/2 as shown above. My brace to gusset weld length is listed as 4" x 9", so perhaps this is where the 4 comes in, but the 1/2 is confusing me. The program they use is DESCON and it gives really simplified equations, with no background information or equation call outs.

Any help on this one?
Thanks.

RC
All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke

 

[Lion06]

The 4 shouldn't be there even if it is referring to the 4" in your call-out........ that is what the "L" is for in the equation.
I have no idea what the 4 or the 1/2 are for. Did you try checking the values that they give against yours? I'm assuming you designed the weld since you called out sizes. If you did design them, then why are they submitting calcs for them?

 

[ARLORD]

I am just guessing without more information:

The 0.5 is the Omega for ASD,
The 4 could be the weld size in 16th's, if w is 1/16.
I am assumung it is a .25" weld.

 

[PEinVA]

ARLORD,
maybe the 0.5 is the (1/Omega) but the D is already called out in the 2nd portion (0.6 * Fexx,..etc.)

SEIT,
We did not design the calcs. We left that up to the detailer. I don't mention the weld size or anything, when I say "My brace to gusset, I really meant the submitted brace to gusset, etc. as provided.

The equation filled out reads
(1/FS)Rn = Beta * 4 * (1/2) * 0.6 * 70 * 0.707 * 0.1875 * 9
(1/FS)Rn = 1 * 4 * (1/2) * 0.6 * Fexx * 0.707 * w * L


I see that the 1/2 could be the Omega, but the 4 should be 2 if it is quantity (both sides of plate) and 4 if it was 9" on all sides, but it is not.

RC
All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke

 

[ARLORD]

RCraine,

I need more info. So it is a 3/16" weld. An "L" shaped weld. How many welds do you have and what are their lengths. This is the weld of the gusset to a beam or column. what is the weld capacity. Is the resultant force at an angle?

 

[PEinVA]

ARLORD and SEIT,
I think I have figured it out after looking at the included section cut at this gusset plate.

ARLORD, to answer your questions, they are using 3/16" in calculations, and the weld in question is be from the brace (HSS9X9) to the gusset plate.

From the section it appears they are planning on getting 9" length of weld in 4 locations (on each side of the gusset plate to the tube in the long direction).
This isn't mentioned in the calculations, only shown in the section.

Thanks for your help on such a simple task of further review on my end.

RC
All that is necessary for the triumph of evil is that good men do nothing.
Edmund Burke

 

[ARLORD]

No problem, that happens to me all the time. Sometimes you overlook the obvious, expecting a more difficult problem.