scope:

This test method covers the procedure for testing vertical or batter piles individually to determine the force and velocity response of the pile to an impact force applied axially by a pile-driving hammer to the top of the pile. This test method is applicable to deep foundation units that function in a manner similar to foundation piles, regardless of their method of installation, provided that they are receptive to high-strain impact testing. These elements can include drilled shafts, micropiles, and continuous flight auger cast piles.

This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific precautionary statement, see Note 7.

Note 1-High-strain dynamic testing requires a strain at impact that is representative of a force in the pile having the same order of magnitude, or greater, than the ultimate pile-soil resistance.

Note 2-This standard method may be applied to the high-strain dynamic testing of piles with the use of either force or strain transducers and either acceleration, velocity, or displacement transducers as long as the test results clearly state how the testing deviates from the standard, i.e., what combination of instruments was used.

Note 3-A suitable follower may be required for testing existing cast-in-place concrete piles. This follower should have an impedance within 50 percent of the impedance of the pile. However, additional caution and analysis may be required if the impedance is not within 10 percent.

Note 4-For mandrel-driven piles, the mandrel may be instrumented in a similar way to a driven pile. However, results from a mandrel that is more than two pieces, one that has joints, will require additional analysis.

The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.