Update from questions asked (AISC and Nucor Fasteners)
Here's what the AISC had to say....
Sorry for the delay in responding...I discussed your question with an ex-fabricator in the office, and I now have the following comments:
1. If possible, make the bolt accesible with access holes.
2. If possible, try using a bolt that is weldable (such as A307). This assumes that you don't have to pretension the bolts, as A307 can't be pretensioned.
3. There are U-shaped clips that are weldable that you could use to "clamp" the bolt head- and weld the clip.
4. If all else fails, you may have to weld the A325. This is not something that is recommended, as you may be damaging the heat-treatment of the bolt by welding to it.
Hope this helps.
Keith Mueller, Ph.D.
AISC Steel Solutions Center
And here is what Nucor Fasteners had to say....
Welding A325 TC or A325 hex bolts would never be our preference or recommendation. Proper tensioning could be compromised by a delayed fracture of the tack weld if the bolt bearing surface was not in full contact with the mating ply. Because there are so may variables, it is hard to say if the fastener would fail consistently due to the welding, but, it could. Technique and experience of the welder definitely could impact the results. Alternatives and solutions are more costly and that is why you hear mostly "thou shalt not" without solutions. The other reason is that most Fastener Engineers are not Structural Engineers and vice versa, therefore, familiarity with acceptable alternatives for problem connections are not common knowledge nor have they widespread publicaton or acceptance. Hopefully, tomorrow's Structural Engineers are learning some practical alternatives in their CE lab classes. The bottom line is that without review & consultation of a particular joint's problems it is hard to offer any constructive ideas/solutions. There may be some products on the market that could offer some assistance in temporary retention of the fastener in the hole until final assembly depending upon the weight of the fastener, but, it will be hard to universally apply them to all joints & assembly situations.
I know this hasn't helped much, but, I'll offer to discuss your assembly needs with you and offer any ideas I may have as your need arises as part of the service we offer at Nucor Fastener Division.
Nucor Fastener Division
Thought I'd share the info that was received,