In recent years, many bracket-less structures are applied at beam-column for convenience of transport and it is welded at field. However, this structure style has backing metal on the outside of lower flange beams, that becomes origin of brittle failure.
In this paper, the new backing-less welding method is examined, which can be welded in overhead position with high-efficiency. Then, its workability and performance is investigated, compare with usual backing-process. At the result, the new backing-less process achieves both workability and improvement of fatigue strength by applying exclusive flux-cored wire.