Need some more info...
D1.6 is for structural stainless.
D1.1 is for structural steel, including some stainless provisions.
D1.5 is for bridges, so if the beam is on a bridge, would apply.
etc., etc.
There are too many different codes/specs that could be applicable to that general combination to be able to answer your question.
Need to narrow down the options through defining specifics.
Tim