Grayson Pump Station

Non-destructive evaluation pilot for a concrete water storage tank

Imagine how exhausting it’d be to drain a 10-million-gallon storage tank every time you needed to inspect defects in the concrete and reinforcing steel—not the most sustainable approach. For aging water infrastructure in Gwinnet County, Georgia, identifying a repeatable, data-driven condition monitoring framework in a non-destructive way was paramount for preventing further subsurface distress that surface observation alone couldn’t characterize. ECS Group of Companies was contacted to develop a proof-of-concept pilot program to evaluate multiple NDE techniques.  

Challenge: Planning for long-term asset condition assessment

The tank had a documented history of localized “patch” repairs with no standardized monitoring protocol in place beyond periodic draining of the tanks and performing manual visual inspections in a confined space. Visible deterioration, including delamination, spalling, horizontal cracks and moisture extrusion, signaled deeper subsurface distress that surface observation alone could not characterize.

Solution: Developing a multi-method NDE approach

ECS deployed GPR, Infrared Thermography and Ultrasonic Tomography (UT) across a shared 2-foot by 2-foot orthogonal grid (a repeating pattern of squares marked horizontally and vertically across the tank surface) collecting GPR profiles at 2-foot on-center intervals per ASTM D6087, ultrasonic profiles at 1-foot horizontal intervals and IRT imaging across a 10-foot by 50-foot vertical section. The grid served as a spatial reference framework, enabling data collection at consistent, documented locations and identifying anomalies from 1.5 inches to 5 inches deep. Future monitoring surveys can return to the same grid points to track deterioration trends over time, establishing a replicable baseline for Gwinnett County’s long-term tank condition assessment program.