Acceptance Criteria of Complete Joint Penetration Steel Bridge Welds Evaluated Using Enhanced Ultrasonic Methods

TRB’s National Cooperative Highway Research Program (NCHRP) Research Report 908: Acceptance Criteria of Complete Joint Penetration Steel Bridge Welds Evaluated Using Enhanced Ultrasonic Methods presents guidelines for evaluating complete joint penetration (CJP) welds in steel bridges and proposes modifications to the American Association of State Highway and Transportation Officials (AASHTO)/American Welding Society (AWS) D1.5.

Inspection of welds in steel bridges is necessary to ensure the quality of workmanship during the fabrication and construction process and later on when the bridge is in service. There are two non-destructive evaluation (NDE) methods for evaluation of complete joint penetration (CJP) welds in steel bridges: radiographic (RT) and ultrasonic (UT). Recent advances in enhanced ultrasonic methods, including the development of phased-array ultrasonic technology (PAUT), allow for efficient detection and characterization of flaws with the option of automated data collection and imaging.

Criteria for categorizing weld discontinuities as acceptable or unacceptable are codified in the AASHTO/AWS D1.5M/D1.5: Bridge Welding Code (BWC). However, these acceptance criteria do not reflect the full use of the capability of enhanced ultrasonic testing methods, and furthermore are not based on the effect of weld discontinuities on bridge performance (e.g., resistance to fatigue and fracture). In addition, some weld discontinuities that are not allowed according to BWC are potentially not harmful and may not decrease service life.

An updated acceptance criteria based on enhanced ultrasonic testing methods for evaluation of CJP welds in steel bridges was needed for fabricators and bridge owners.