<p><p><strong>Reference(s):</strong></p><p><em>Brown et al. (2007)</em></p><p><strong>Method Summary</strong></p><p>Post-construction integrity testing is best used to verify that the production parameters (penetration speed, grout/concrete pressure and volume, etc.) are appropriate for the site conditions to produce piles with the desired properties and without defects. Types of integrity tests include the sonic echo test, cross-hole sonic logging (CSL), single-hole sonic logging (SSL), and the backscatter gamma test.</p><p>The sonic echo test is performed by striking the top of the pile with a small instrumented hammer and thereby sending a compressive wave down the length of the pile. The wave is reflected at the toe of the pile and is measured at the surface. In the event that there are any discontinuities or defects in the pile, the wave will be reflected prior to reaching the toe of the pile. Sonic echo testing is recommended for piles less than 30 inches in diameter.</p><p>CSL is conducted with a source in one tube and a receiver in another. A strong signal measurement with a time that is consistent for strong grout/concrete is an indicator of quality. SSL uses a source and receiver in the same tube and measures the wave speed of the material surrounding the tube. The backscatter gamma test or gamma-gamma logging uses a radioactive source on one end of a probe to emit gamma photons with a detector on the other end. The photon count is calibrated to the grout/concrete density within a radius of about 100 mm (4 in.) around the tube.</p></p>