Actually, I have now found my A3.0 and see that what I thought you were talking about is nothing at all like Fig 24(F). I thought it was as shown in Fig 3, the part labeled "joint filler" (page 49).
I don't see such a joint shown in AWS D1.5 Figures 2.4 and 2.5. (D1.1 has the B-U3a joint but that is not prequalified for bridges.) My opinion is that you could use that joint but it would need to be qualified under D1.5 - 5.13.
Short answer: no.
Long answer:
I don't think they could, at least not for a tension joint. That spacer makes the joint a PJP instead of a CJP, and in addition it reduces the depth of the weld from full-section.
The only place I've seen anything resembling a filler used to make up for poor fitup in D1.5 welding is in a T joint like a stiffener-to-flange weld with double fillets. And even then, it's not that simple. They do pretty much as Figs. 2.1 and 2.2 do in D1.5--if it's a very thin filler, they cover it with the fillet weld but increase the weld size by the size of the filler (because the filler subtracts from the effective throat), and for a thicker filler, they have two separate sets of welds--one from the stiffener to the filler plate, and another set from the filler plate to the flange--and each set has to be able to transfer the same load the original stiffener-to-flange welds would have transferred.
Just stuffing some metal in the joint and then welding as if nothing happened is "slugging" and not allowed in bridge welding.
Whether you could do it with a PJP...it certainly wouldn't be one of the standard Fig. 2.5 joints and so would need to be qualified under 5.7.7. I suppose it might not be any worse structurally with two notches at the root than one, if they're close enough together, but nevertheless it would require separate qualification of the joint--and a separate PQR and WPS if not SMAW. And you'd probably need to get the engineer's approval to make sure that the two notches don't make some kind of hinge or something. All in all, not the sort of thing one could just do on the fly to fix some bad fitup.
Hg
Thanks. That was my gut reaction. I consider it slugging and even if the contractor wants to weld from both sides he has probably violated the code. A frequent repair technique includes cutting the bottom flange and a portion of web from an exterior beam. Then using a WT, weld it back in and bolt splice the ends. Even if this is executed properly, I'm not too sure about it. But when there is poor fitup between the webs of the existing and the WT, contractors often try and slip a slug in there. We use 100% radiography so we catch them when they try it, but it is a big hassle.
The joint could be made as a CJP with backgouging to the 2 roots - thus a non-standard joint. Practical? Possibly not depending on circumstances. Controllable? It would be something to keep a close eye on. Naturally, owner/engineer approval is required. It might be better to cut off a foot and CJP splice a section to restore proper length, that is if a new and longer piece cannot be provided.
I would not expect to see such a joint approved for shop work or new construction. However, I would not rule out the possibility of using spacers for difficult situations, especially as is often seen on rehab bridge projects.