dbuzz and Lutfi - Are we talking about the same thing? I agree that in general shop weld and field bolt is the way to go, but I'm not talking about something like welding double angle shear connections at each end of each beam to columns. I'm only dealing with x-bracing connections. If you are using bolts for x-bracing connections, do you use oversize holes, and do you specify anything more stringent than snug tight? If I were using the brace as a compression brace, I think (not everyone I talked to agrees on this) it would fall under the heading of "built-up members", E4 in the AISC Spec. The last sentence of the third paragraph of E4.2 reads: "The end connection shall be welded or fully tension bolted with clean mill scale or blast-cleaned faying surfaces with Class A coatings." The commentary doesn't say much about it, but I'm assuming that that rule is there to keep one angle from taking the full compression load until it buckles and then overstressing the second angle. I'm not sure that the issue is the same for tension only, since if one angle were overstressed because of an imperfect connection, the overstressed angle would just yield and then the overload would be taken immediately by the other brace; but still, there's the matter that if only one angle is engaged, then the bolts must be acting in single shear instead of double shear, and there may also be issues in the field if the connection is detailed with standard size holes and accumulated imperfections do not allow the brace to match up with the gusset plate as detailed. Any opinions on this?
