4.1 Based on the measurements of strain and acceleration close to the pile top, possibly combined with those from accelerometers or strain transducers located further down the pile, this test method assesses the pile top velocity and force in response to an axial impact force.

4.2 The mobilized compressive axial static resistance is derived from the test data and is therefore an indirect result. Test Method D1143/D1143M provides a measurement of static resistance at the time of testing.

4.3 The Engineer should ensure that the test as specified will generate the sufficient axial load and displacement to meet the purpose of the test. In case that purpose is to establish geotechnical failure, the Engineer should also ensure that impact force results in significant permanent axial displacement during the test.

4.4 The Engineer may analyze the acquired data using engineering principles and judgment to evaluate the performance of the test equipment and the characteristics of the pile's response to the impact force. If the test is used to evaluate the integrity of the pile the Engineer should understand that the data resolution allows for misinterpretation or masking of integrity issues from stress wave reflections from changes in soil parameters along the length of the pile. For cast-in-situ piles the Engineer shall pay special to variations in concrete properties and the pile cross section along the length of the pile. This is especially important when strain transducers near the pile top are used to obtain the impact force, since the modulus of elasticity near the transducers may not be the same as the average over the pile length.

4.5 The scope of this standard does not include analysis for foundation capacity, but in order to analyze the test data appropriately it is important that information on factors that affect the derived mobilized axial static capacity is properly documented. These factors may include, but are not limited to, the: (1) pile installation equipment and procedures, (2) elapsed time since initial installation, (3) pile material properties and dimensions, (4) type, density, strength, stratification, and saturation of the soil, or rock, or both adjacent to and beneath the pile, (5) quality of test data, and (6) final foundation settlement.

4.6 The accuracy of the derived results may improve when using additional strain transducers and accelerometers embedded in the pile, as this may allow validation of the signal matching results with agreement between the additional measurements.

Note 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it and the suitability of the equipment and facility used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some, but not all, of those factors.

1.1 This test method covers the procedure for testing an individual deep foundation element to determine the velocity and force response to an axial impact force with a pile driving hammer or a drop weight that will cause a relatively high strain short duration pulse at its top in order to evaluate pile driving performance and/or static load-displacement behavior. This non-static foundation test method applies to all deep foundation units, referred to herein as “piles,” that function in a manner similar to driven or cast-in-place piles, regardless of their method of installation.

1.2 This standard provides minimum requirements for testing of deep foundations under an axial impact force. Plans, specifications, or provisions (or combinations thereof) prepared by a qualified engineer may provide additional requirements and procedures as needed to satisfy the objectives of a particular test program.

1.3 The engineer in charge of the foundation design is referred to herein as the “Engineer.”

1.4 The proper conduct and evaluation of the test requires specialized knowledge and experience. A qualified engineer should directly supervise the acquisition of field data and the interpretation of the test results so as to predict the actual performance and adequacy of deep foundations used in the constructed foundation. A qualified engineer shall approve the apparatus used for applying the impact force, driving appurtenances, templates, and test procedures.

1.5 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. The word “shall” indicates a mandatory provision, and the word “should” indicates a recommended or advisory provision. Imperative sentences indicate mandatory provisions.

1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this test method.

1.7 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.

1.7.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that should generally be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analysis methods for engineering design.

1.8 The method used to specify how data are collected, calculated or recorded in this standard is not directly related to the accuracy to which the data can be applied in the design or other uses, or both. How one uses the results obtained using this standard is beyond its scope.

1.9 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For a specific precautionary statement, see Note 3.

1.10 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.