Portable Seismic Pavement Analyzer (PSPA)

The Portable Seismic Property Analyzer (PSPA) is a seismic device used to evaluate the strength of concrete structures and both flexible and rigid pavements. It operates according to the principles of the Spectral Analysis of Surface Waves (SASW) where material properties of a layer are evaluated based on the response of the surface due to induced seismic waves.

The system consists of a seismic source, two receivers (one “near” the source and one “far” from the source), an electronic control box, and a computer for data collection. When testing, the seismic source impacts the surface to induce seismic waves in the surface layer. These waves travel through the surface layer and are detected as vibrations as they travel past the receivers. These signals are used to determine the wave velocity of propagation, which is based on the wavelength and frequency of the induced waves. The recorded signals are evaluated by the system’s software to determine the seismic modulus and thickness of the surface layer.

The PSPA is an easily portable device that can be reconfigured based on the thickness of the pavement layer being evaluated. A modified version, known as the D-PSPA, is designed for use with unbound materials. Both types of devices can be used for one-time evaluations of the surface structural properties or for monitoring the change in those properties with periodic evaluations.

PSPA Operation in the Field (Click to Zoom)

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