# FW: Maximum Weld Size ( was Welding Tubes )

• To: "'seaint'" <seaint(--nospam--at)seaint.org>
• Subject: FW: Maximum Weld Size ( was Welding Tubes )
• From: "La Count, Curt" <Curt.LaCount(--nospam--at)Jacobs.com>
• Date: Fri, 11 Feb 2000 08:08:00 -0800
```Jake,

No mater how big your weld is, you can not design more strength than the
connected parts.  I use an effective weld concept to calculate joint
strength.  Equate the weld strength to the strength of the connected part
and solve for the fillet weld thickness.

.9 * Fy * t=.75 * .6 * 70 ksi * .707 * aeff  for a single weld and tension
application.

If you have a Salmon and Johnson text, this concept is shown in Chapter 5.

Welding to the face of hollow structural sections is complicated by the
flexibility of the tube wall and for the tendency for the weld to unzip.
For this specific situation see the AISC Hollow Structural Sections
Connections Manual.

Curt La Count
Jacobs Engineering
Portland, OR
----------
From: Jake Watson
To: seaint(--nospam--at)seaint.org
Subject: Re: Welding Tubes
Date: Friday, February 11, 2000 6:25AM

Correct me if I am wrong, but the thickest fillet that can be considered
as effective is the thickness of you thinnest element.  So if you have a
1/4" col, the thickest fillet weld that can be used for calculations is
1/4".

Jake Watson, E.I.T.
Salt Lake City, UT

```