By -
Date 02-18-2005 15:59
Hey Mike,
Yeah that was a good article. You can find it in the Fall 2004 issue of Inspection Trends.
Drafters always have difficulty with welding symbols for tubular TKYs. It is usually necessary to add a note stating that the welding be in accordance with some sort of procedure that fully details what needs to be done.
As you say, if you have a 22"OD brace member intersecting a 38" chord member at a 45 degree brace intersection angle, the groove angle at the heel of the joint cannot be 45 degrees. Refer to Table 3.6 of D1.1, where for a 45 degree dihedral angle (at the heel of the joint the dihedral angle is equal to the brace intersection angle) you will find that the maximum allowable groove angle is 40 degrees. That is too large (lay it out and see what kind of weld volume you end up with). The minimum allowable is 1/2 the dihedral angle, which in your case will be 22.5 degrees. This should work okay for you.
Be aware that if this is a D1.1 job:
1. The WPS needs to be qualified, and you'll need at least a 6GR test and an acute angle heel test to accomplish that (refer to section 4.12). Your project documents may require additional testing, such as impact, hardness, CTOD, etc.
2. The welder will also need a 6GR and an acute angle heel test (refer to section 4.26, Table 4.9, Figures 4.26 and 4.27).
Find that article if you can. It will tell you how to do the fitup inspection and reference point marking, which will allow the weld to be completed in accordance with the code.
Hope this helps,
Mankenberg