Fit up question

Date 03-18-2013 19:56

Hi all,
I have a fit up tolerance question for everyone. We subcontracted a project to another fabricator with HSS 10x10x5/8 columns with 1/2" thru plates welded with 5/16” fillets. The slot cut in the wall of the HSS would typically be 9/16” to 5/8” wide to allow the 1/2" plate to pass thru the column. While I was down there inspecting I saw slots between 3/4" and 7/8” thus creating a gap of 1/8” to 3/16” on each side of the plate. Per D1.1 2010 sect. 5.22.1 they are within tolerance for the gap size. My question is….. if a bead of weld metal is placed covering the gap (not filling the full thickness of the col…5/8”), do we still have to increase the fillet weld legs by the size of the gap? Typically in my shop, I tell the guys to increase the fillet size by the size of the gap regardless. This shop said their standard practice was to run a “root pass” to fill the gap and then lay the required 5/16” weld on top. My assumption is the effective throat no longer starts at the theoretical intersection of the plate and wall of the HSS, but rather the edge HSS. Which shop is correct? Any and all comments are welcome.

Thanks,
Ed

By welderbrent (*****)

Date 03-18-2013 21:05

Ed,
Just running a 'buttering' pass over the gap does not increase the strength of the area properly to justify leaving the leg size, and thus effective throat, of the fillet short. The leg size does not have the proper support strength from the HSS until you get to the full dimensional thickness of the HSS. To get the strength required out of the joint they would either have to CJP the joint first or else follow the Code and increase the leg size to get the correct throat and thus the correct strength.

Now, let's see what everyone else thinks.

Have a Great Day, Brent

By 803056

Date 03-18-2013 22:06

Sound good to me.

Al

By Tommyjoking (****)

Date 03-19-2013 00:05

You got the right answer. It is common engineering practice to increase fillet size to accommodate gaps in the field....this ends up with a helluva good root/penetration if applied/cleaned properly. The additional size of the fillet ensures surface area coverage in case the "butter passes" were not laid in correctly. As I non-CWI proffessional welder/journeyman Mech engineer I totally concur with this method. LOL. :evil:

By Smooth Operator (***)

Date 03-19-2013 01:20

I agree also......but I'm lookin' for an xtra($$$$$) for my time & weld wire I gotta use to fill some lunkhead lazy hacks fit up...... :eek:

1/16"both sides = 1/8" wide if you can't keep that "tolerance" you better get a different job (weld grinder comes to mind) :yell:

Tommy I know you or Cummins wouldn't accept this !!!!!! :yell:

By Duke

Date 03-19-2013 02:46

Regardless of 'root pass' or buttering, fillet weld gets bumped up by root opening, if you don't, you don't get enough bite on base metal..

By eekpod

Date 03-19-2013 10:52

I agree also, this is how we would handle the same situation, fill/butter the ends up, but still install the increased sized fillet over it.

By Cumminsguy71 (*****)

Date 03-20-2013 21:54 Edited 03-20-2013 21:57

That tower I welded on the engineer specified on the prints that the material we were adding would most likely have "gaps". For gaps up to a certain size he increased the size of the weld by 50% according to gap size. For other gaps he called out using a filler material, "A36 or equivalent" to fill the gap and increase the weld size accordingly. The CWI report the CWI has called out the gaps and he has raised questions about the size of the gaps(1/4", also noted on engineered drawings and welded as per engineered drawings) and recommended that we contact the EOR. Hmmm, apparently he can read welds but not prints.

Depending on what your doing you might want to make sure that everybody is on the same page. On our project as I said the weld size was increased by 50%, 1/8" gap, 1/4" weld, 1/4" gap, filler metal and 1/2" weld.