Testing of In-Service Bridges Using Automated Ultrasonic Testing Methods

Identifying the location, size, and extent of weld defects or flaws can be critical for ensuring bridge safety. Current bridge-inspection practice relies primarily on visual inspection for detecting cracks but is not capable of detecting subsurface weld defects that may develop into cracks under service loading.

Other technologies such as conventional ultrasonic testing (UT) and radiographic testing (RT) can detect subsurface flaws, but are used primarily during the bridge-fabrication process because the technologies are difficult to apply to in-service bridges.

For RT, the geometry of in-service welds often precludes the proper alignment of the source and film, and required safety precautions for RT can limit practical application.

For UT, the method requires a high level of expertise to implement and results can have uncertain resolution and accuracy because the method relies on an inspector’s ability to effectively scan critical areas manually and interpret relevant indications.

TRB's Highway Innovations Deserving Exploratory Analysis (IDEA) Program Final Report 191: Testing of In-Service Bridges Using Automated Ultrasonic Testing Methods aims to investigate the effectiveness of Automated Ultrasonic Testing (AUT) to improve the resolution, accuracy, and reliability of inspections.