I have read those sections, which is why I posted the question. What is the tack welding certification requirements that cover T,K,Y connections. Or am I missing something here.
I think you missed the last sentence which basically indicates that only welders fully qualified to weld T-K-Y connections can tack weld T-K-Y connections in the process and position in which the welding is to be done.
Al, you are correct the D1.5 Defaults all tubular to D1.1 even if it is used on a bridge. (Section 10 Tubular Structures "No Applications Within This Code")