Supplemental Ultrasonic Code Inspection of Structural Weldments

This work addressed two issues pertaining to the ultrasonic inspection of steel-moment-frame buildings that may have suffered damage as a result of the 1994 Northridge earthquake ground motion. These were: (1) Are the AWS D1.1 Code procedures reliable enough to detect flaws in the structural weldments of interest? and (2) Are there alternative Code-supplemental procedures that can be applied manually for not only improved flaw detection, but also flaw location, classification, and sizing? Twelve mockup specimens containing a total of 17 intentional worst-case-scenario flaws in representative beam-to-column weld geometries were fabricated. The Code-based detection results were marred by four misses and more than ten false alarms. In contrast, use of Code-supplemental procedures assured that no intentional test flaws were missed and false alarms were kept to a minimum. Only the Code-supplemental advanced procedures were used to characterize (as to type, location, orientation, depth, and length) a detected test flaw. In 95% of the measurements, the XYZ flaw location, length, and depth estimated were within 5 mm (0.2 in.) of the intended values.