抄録
This paper describes the results of investigations carried out in field welding using ultrasonic examinations, on the locations where defects frequently occure and on the welding conditions under which they frequently occur. The investigations were carried out on three skyscrapers and ten middle-rise steel buildings. Welding defects occur more often in the lower flanges of beams connected to columns, at the roots of grooves, in cases of root openings being narrow, and on Mondays and Saturdays. Minor defects are commonly produced when the discomfort index is too high or too low, but major defects are unrelated to this index. Defective joints are not produced at a uniform pace during construction, but at fluctuating rates.
