Many bridges are constructed using pinned supports to connect different areas of the structure. When the load is transferred from one area of the structure to another through the pin, it can make the two points of contact within the pin susceptible to shear. Consequently, the pins are regularly inspected as part of the structure’s maintenance program.
Using nondestructive phased array (PA) technology to test bridge pins can help make the inspections faster. In addition to testing for shear stress, the PA method can also be used to detect corrosion and fatigue cracking.
A bridge pin supporting hangar plates. (Image from US Department of Transportation https://www.fhwa.dot.gov/publications/research/infrastructure/structures/04042/02.cfm )
The A24 probe on a bridge pin.
How We Can Help
When performing bridge pin inspections, the faces on each end of the pin are the only accessible points. To perform the inspection using the conventional ultrasound technique, multiple transducers are required to cover the pin’s depth. A phased array inspection, on the other hand, provides a full volumetric inspection with just one transducer, increasing productivity for faster inspections.
Our A24 probe used with an with OmniScan® SX flaw detector is an excellent solution for bridge pin inspections. The A24 features a 2.0 MHz or 4.0 MHz probe with 16 elements, 1 mm pitch, and 16 mm elevation. It has a transparent replaceable wear face for contact inspections and can sweep +/- 30 degrees to cover the full range of the pin. The A24 is the only probe you need to get the job done.
Conclusion
Inspecting different types of bridge pins using phased array technology helps users save time and reduce cost. Detecting critical flaws, such as corrosion, fatigue cracking, and/or shearing before a catastrophic failure, helps make our global bridge infrastructure more secure.
