Date
Monday, July 20, 2026
Time
1:30 PM - 2:00 PM
Location Name
Room 5, Level 2
Name
Microscopic Waves, Massive Impact: A Case Study in VibroAcoustic Innovation
Track
Distribution
Description
Innovations in water pipeline condition assessment are advancing rapidly. Only two years ago, acoustic transit-time testing represented the latest breakthrough; today, that method already feels outdated. Vibroacoustic testing—injecting microscopic waves with an added vibration component into pressurized water mains—has now emerged as a practical, field ready solution. By shifting from time domain to frequency domain analysis, this solution is finally moving from decades of promise to everyday application in water distribution systems. This presentation examines a case study from Addison, Texas, to demonstrate the capabilities of Advanced VibroAcoustic Analysis (AVA) powered by Dynamic Response Imaging™ (DRI). AVA is a non-invasive and affordable tool that provides accurate condition assessment using external access points such as hydrants, valves, or temporary potholes. The technology uses nonlinear vibroacoustic signals tuned to pipe material and diameter, exciting the entire pipeline so that its resonance frequencies—directly tied to wall stiffness—can be measured and interpreted. The Town of Addison, located north of Dallas, serves 17,000 residents through 101 miles of water mains supplied by Dallas Water Utilities. In its most recent water system master plan, several pipelines were listed on the capital improvement project (CIP) schedule based on age, service usage, and consequence-of-failure criteria. In December 2024, Addison contracted RJN to inspect a priority segment using the AVA process. The segment consisted of roughly 400 feet of 8 inch ductile iron pipe installed in 1978 beneath a parking lot along Belt Line Road. Using a wave generator, AVA introduced microscopic vibroacoustic signals into the pressurized main at multiple frequencies. The pipe’s dynamic response—its vibration across a range of resonant frequencies—was captured using paired sensors and analyzed through cross correlation techniques. By scanning the pipe at multiple wavelengths, AVA characterizes the stiffness of each short segment, allowing engineers to derive a residual wall thickness profile at 5 to 10 foot resolution. This ensures that localized defects are captured rather than averaged out across long pipe lengths. The system also identifies leaks, air pockets, and tuberculation. The original wall thickness of the inspected pipe was 0.270 inches. AVA results showed that 51 of the 60 pipe sticks (85%) retained sufficient or better strength, while 9 sticks (15%) showed marginal strength but no critical deterioration. The average remaining wall thickness was 0.216 inches (80% of original), with values ranging from 0.168 inches (62%) to 0.263 inches (97%). No leaks, air pockets, or interior tuberculation were detected. The analysis revealed uneven deterioration rates, with several pipe sections aging more slowly than expected for ductile iron. Assuming future conditions remain stable, these segments are projected to exceed typical life expectancy models. Based on the results, the engineering recommendation was to re inspect the line in five years to better define long term degradation rates. Thanks to this inspection, the Town of Addison can defer replacement and remove the pipeline from its CIP priority list. Funds earmarked for premature replacement can now be redirected to higher need projects, allowing the asset to be managed based on true condition rather than age alone.