Spectral Analysis of Surface Waves (SASW)

The SASW method uses the dispersive characteristics of surface waves to determine the variation in shear wave velocities with depth within layered concrete systems. The method is non-destructive and only requires adequate accessibility to the concrete surface. The shear and Young’s modulus can be readily determined once the shear wave velocities are obtained. SASW investigations are typically performed to:

  • Evaluate the Depths of Cracks in Concrete
  • Assess the Condition of Concrete by Providing Shear Wave Velocities (Stiffness) of Layered Concrete Systems with Depth (e.g. Slabs or Tunnel Linings).
  • Evaluate Fire Damage Throughout Concrete

GeoView uses the Olson Instruments ND-360 with the SASW-S instrument package. This configuration allows for the assessment of concrete conditions to an approximate depth of 0.8 m (2.6 ft). Data can be collected rapidly and evaluated in the field. 


The SASW can be used to determine crack depth. In this case it was used to confirm that the horizonal cracks within this column did not extend deeper than the rebar cage

Collection of SASW data