As the nation’s bridge inventory deteriorates and structural performance conditions worsen, agencies must increasingly make difficult decisions on allocation of limited resources to maintain a safe and functioning inventory. Current bridge inspection practice is to use conventional testing methods like ultrasonic (UT) and radiographic (RT) test methods that tend to provide low overall resolution evaluations of a bridge’s condition, which can lead to unnecessary repairs or catastrophic failure. To increase this resolution in a cost-effective manner and at the same time improve the accuracy and reliability of the measurements the present study sought to investigate the effectiveness of automated ultrasonic testing (AUT). The project team developed a prototype test system using a low-cost ($500) X-Y plotter as its basis, leveraging its capacity for precision, programmable movement of an integrated Phased Array Ultrasonic Testing (PAUT) probe. The AUT prototype was tested on laboratory specimens with manufactured weld flaws and in the field with the resulting output of the system being compared to the output gathered by ASNT III UT inspectors. Based on this comparison, the AUT prototype was found to produce data of quality equal to that of the manual inspectors while executing an automated routine for gathering such data. In reviewing the use of PAUT, both the manual and automated inspections demonstrated the importance of grinding welds flush to the joint to minimize noise. Despite the similarity of results between the AUT system and manual inspectors, the challenges of mounting and deploying such a system on bridges of unknown or variable configurations were not resolved, making the system more relevant to production welding environments where the automation aspect could be more appropriately utilized.
The final report is available.