Double fillet weld corner joint
Double fillet weld corner joint
(OP)
We manufacture steel connections for the heavy timber industry (glulam). Our typical weld detail is a fillet weld as shown in the attached drawing. I recently had an Engineer say that this was not an approved weld for the given loading (top mount hanger). does this joint not fit under prequalified welded joints - fillet welds Table 8-2 AISC Steel Construction Manual?






RE: Double fillet weld corner joint
Best regards - Al
RE: Double fillet weld corner joint
I'm not a weld engineer or anything, but I suspect that regardless of whether it meets the letter of the prequalification it may not meet the spirit of it, given the way the roots basically meet like that. You're also going to fuse the same base metal twice because they're so close.
RE: Double fillet weld corner joint
http://eng-tips.com/viewthread.cfm?qid=358309
RE: Double fillet weld corner joint
For your static application, that weld detail should probably be o.k., but there are several issues that you have to resolve in your own mind. I’m not a great one for worrying that some code approves every exact detail, in every respect. I would sooner that we understand the basics, the areas of potential troubles, and then use good engineering judgement, design and engineering mechanics. Gtaw gives good counsel, and I am not sure that you need a new WPS for every possible detail. But, you do need to know welding design and your own processes and welders, so you know what they can and can’t do.
On the detail you show, the welds can certainly be sized to take the static loads. But, the potential problem that I see, and the objection that the other engineer may have had, is that the flow of the tensile stresses/force fields is perpendicular to and flows across the two unfused roots of the two fillet welds. And, this is not a very acceptable condition, since it can start cracking at the roots. There is a good chance that the first weld will penetrate through the small root face (land) which you have; and the second weld will remelt this, boil-out any impurities and give you essentially a full pen. weld. You should run some samples of this, and test your welders to prove that this is true. Alternatively, you could grind or gauge that root area before making the second weld, then there should be no question of trapped junk causing imperfections which are perpendicular to the stress field. You also have to be careful how you start and stop these welds at the two edges of the plates, so that these areas are properly finished and don’t become crack starters. You could likely break form that top flange on the back plate and hide any minor length variations behind to bottom bearing plate.
RE: Double fillet weld corner joint
RE: Double fillet weld corner joint
Why not use a piece of bent plate and/or angles to build this connection?
Sort of like this:
http://www.strongtie.com/products/connectors/GLS-H...#
RE: Double fillet weld corner joint
Best regards - Al
RE: Double fillet weld corner joint
Unless this is a fluid-tight corner, don't weld it like you propose.
RE: Double fillet weld corner joint
RE: Double fillet weld corner joint
RE: Double fillet weld corner joint
The structural code has no limitations on the size of the fillet weld unless the joint is a lap joint ref. AWS D1.1-2010, clause 2.4.2.9(2)). The weld can be built out to the full thickness of the plate in an outside corner joint and it can be as large as necessary on the inside o the corner joint.
The double side welded joint is a partial joint penetration weld unless there is a back gouge operation. As PJP or a fillet weld, the efficiency of the joint is limited. The maximum unit stress is 0.3 time the tensile strength of the filler metal, but not more than 0.4 times the yield strength of the base metal. AWS D1.1-2010, Table 2.3 provides the designer with the allowable stresses per the structural welding code.
In any case, the details of the design are subject to the review and approval of the Engineer representing the Owner's interest. As a fabricator, I would suggest the standard designs/details be reviewed and approved by a registered structural engineer.
Best regards - Al
RE: Double fillet weld corner joint
RE: Double fillet weld corner joint
RE: Double fillet weld corner joint
I can see where the fabricated hanger would conform to the beam better than a bent plate.
Best regards - Al
RE: Double fillet weld corner joint