| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for repairing a fatigued beam structure having a defective flange gusset, by which consumption of metal becomes small, efficient work becomes possible, and high durability is achieved. SOLUTION: The fatigued crack portion of the beam structure having a flange gusset is removed so as to be longer than the longest crack among the fatigued cracks on the face side or the back side by at least 10 mm. Next, the fatigued crack portion is repaired by welding as a repaired welded portion 5. The shape of the toe of the repaired welded portion 5 is improved by forming grooves on the whole periphery of the toe of the weld of the repaired welded portion 5 by carrying out the ultrasonic impact treatment at a temperature not higher than 100°C. At the same time, a toe portion 6 of the flange gusset, which is located at the position withdrawing from the treated portion by at least the thickness of the flange, is treated by the ultrasonic impact treatment within the region apart from the toe by at least t, where t shows the thickness of the flange gusset. COPYRIGHT: (C)2004,JPO
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