Non-Destructive Testing

Non-destructive testing plays a vital role in YA Group’s investigations and allows us to determine the extent and underlying cause of distress in all kinds of buildings and structural components. While traditional load testing or destructive testing approaches can be effective, they are often invasive, time-consuming, and expensive. In contrast, non-destructive evaluation (NDE) methods enable us to gather a clear picture of existing conditions and material characteristics while also identifying signs of distress without modifying or damaging the structure. Used independently or alongside conventional testing and analysis, these techniques provide meaningful insights.

Non-Destructive Testing Methods include:

• Corrosion rate assessment
• Half-cell corrosion potential
• Mild reinforcement and post-tensioning detection
• Thickness of concrete studies
• Ground penetrating radar
• Impact echo testing
• Ultrasonic pulse velocity testing
• Shear wave ultrasonic tomography

Digester Tank 3 is a reinforced concrete tank, constructed circa 1950, that measures approximately 100 feet in diameter and has a nominal 16-inch-thick wall. At the top of the wall, the section tapers inward, forming a 10-inch high by 12-inch-wide concrete curb. Shortly after a new roof membrane was installed, portions of the concrete curb ring failed, causing the membrane to collapse.

UPV testing produced an average P-wave velocity of approximately 11,700 ft/s around the curb perimeter, indicating concrete of marginal quality.

GPR testing identified two layers of vertical reinforcing bars, spaced roughly 12 inches apart. The data also showed that the vertical bars did not extend into the upper portion of the curb. GPR additionally confirmed the presence and spacing of anchor bolts, interior bolts at 12 inches, and exterior bolts at 8 inches.

Combined NDT results guided the selection of core sampling locations for laboratory compressive strength and petrographic examination.