# RE: Max weld size

• To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
• Subject: RE: Max weld size
• From: Charlie Carter <carter(--nospam--at)aiscmail.com>
• Date: Wed, 26 Apr 2000 14:28:48 -0500
Title: RE: Max weld size

Equation 1 below is not a maximum fillet weld size. It is a reversed calc. from LRFD Manual page 9-15  to determine the minimum beam web thickness to support a pair of fillet welds of a given weld size (D sixteenths). Essentially, that relationship is calculated by matching the shear yield strength of the base metal to the shear rupture strength of the welds.

D = 0/75t is a relationship of the same origin for which the resulting weld size will develop the strength of the base metal thickness t.

Hope this helps.

Charlie

-----Original Message-----
From: Harper, Mark [mailto:MHarper(--nospam--at)hdrinc.com]
Sent: Wednesday, April 26, 2000 10:44 AM
To: 'seaint(--nospam--at)seaint.org'
Subject: Max weld size

My question is this.
When placing a fillet weld on both sides of the same plate (such as a shear
tab to column or HSS brace to gusset plate)  I have run across two formulas
to determine the max. allowable fillet weld size for a given thickness of
plate.
1. D=t*Fy/5.16, Where D is in 16th's. (LRFD manual Vol. II, AISC)
2. D=.75t  Where D is in inches.(The Procedure Handbook of Arc Welding,
Lincoln Electric)
Are both formulas valid?
I believe #2 is meant as a quick approximation, but was just wondering if
anybody has used these formulas.  The answers very greatly depending on
plate strength. Also does anybody know how #1 is derived?
Thanks,
Mark Harper PE, SE
HDR INC.
mharper(--nospam--at)hdrinc.com
Phone: (626) 564-2820
Fax: (626) 564-2873

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