Innovation in Non-Destructive Seismic Testing

Applications 12/5/09

The civil engineer's dream is the black-box that can scan a road or structure, and report the time and the manner in which it will fail. We wish we knew how to build that black-box. Every measurement we know how to make, whether seismic, nuclear, or electromagnetic, gives only an indirect estimate of remaining life. Seismic-wave measurements are less indirect than others, and have several major strengths in realizing the ideal measurement.

The seismic modulus or stiffness is directly related to the square of velocity of stress-wave propagation.

Velocity/modulus reductions are measurable years before surface distress appears.

Life-cycle feedback becomes possible. The same physical property is measured in the lab for material selection and design, in construction test cylinders for material quality control, in-situ for construction quality control, and in-situ over the lifetime of the pavement for performance evaluation.

High-frequency, low-strain measurements are linear, precise, and non-destructive, giving cost-effective laboratory characterization of aging, compaction, moisture, strain, and temperature dependence.

In-situ measures of construction quality are at stress and strain levels comparable to laboratory measurements.

The remediation effectiveness can be measured.