ASTM D pile integrity testing. ASTM E A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. Scope 1.
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ASTM D pile integrity testing. ASTM E A number in parentheses indicates the year of last reapproval. A superscript epsilon e indicates an editorial change since the last revision or reapproval. Scope 1. This test method is applicable to long structural elements that function in a manner similar to foundation piles, regardless of their method of installation provided that they are receptive to low strain impact testing.
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 and health practices and determine the applicability of regulatory limitations prior to use.
Referenced Documents 2. Terminology 3. Current edition approved November 10, Published November Originally published as D — Last previous edition D — This data assists evaluation of pile integrity and pile physical dimensions that is, cross-sectional area, length , continuity, and consistency of the pile material. This test method will not give information regarding the pile bearing capacity. The time domain record is then evaluated for pile integrity. The data are evaluated usually in the frequency domain.
Apparatus 5. A hammer with a very hard plastic tip can induce a short input force pulse without causing local pile damage. The impact should be applied axially to the pile normally on the pile head. The accelerometer s should be placed at or near the pile head and shall have their sensitive axis parallel with the pile axis.
Accelerometers shall be linear to at least 50 g. Alternatively, velocity or displacement transducers may be used to obtain velocity data, provided they are equivalent in performance to the speci? If damage is suspected during use, recalibrate or replace the accelerometer.
The hammer may have a force load cell between the tip and hammer body. Alternatively, the hammer may have an accelerometer attached and the measured acceleration may be converted to force using the hammer mass.
The hammer must be tuned such that the fourrier transform of the measured force shall have a smooth spectrum, without any local peaks. The motion sensor is placed generally near the center of the pile. Additional locations should be considered for piles with diameters greater than mm.
The low strain impact should be applied to the pile head within a distance of mm from the motion sensor. If the pile head is not accessible, as when already integral with the structure, the sensor s may be attached to the side of the pile shaft.
The apparatus shall include a graphic display of velocity and force optional , and a data storage capability for retrieving records for further analysis. The apparatus should be capable of averaging data of several blows to reinforce the repetitive information from soil and pile effects while reducing random noise effects. The apparatus shall be able to apply increasing intensity ampli? The apparatus must have? The apparatus shall be capable of transferring all data to a permanent storage medium.
The apparatus shall allow for a permanent graphical output of the records. A typical schematic arrangement for this apparatus is illustrated in Fig. When digitizing, the sample frequency, therefore, shall be at least 30 Hz each for the motion sensor and the optional instrumented hammer, if used. The uniformity and accuracy of the digital sampling frequency is critical; the clock jitter sampling frequency accuracy must be within 0.
Analog data acquisition systems are speci? Attached to every digitized event should be identifying information names and descriptions, signal processing enhancement parameters, and date and time stamps. The apparatus shall balance the velocity signal to zero between impact events. The force output shall be balanced to zero between impact events. This apparatus may receive the signals after they have been processed by the apparatus for reducing the data.
The apparatus shall display the digitized data of the impact event or upon recall by the user of the digitally stored event. Adjust the apparatus to reproduce a signal having a range of duration between 2 ms and 30 ms. Ensure that the apparatus is capable of displaying the signal from each selected blow for a minimum period of 30 s. Procedure 6.
Attach the appropriate motion sensor see 5. Average the suitable records of several impacts and apply necessary ampli? The records from the individual impacts or the averaged record, or both, should then be stored see 5. The averaged, ampli? Ensure that the pile head surface is accessible, above water, and clean of loose concrete, soil or other foreign materials resulting from construction. If the pile head is contaminated, remove a sufficient pile section to reach sound concrete.
If necessary, prepare small areas by a hand grinder to provide a smooth surface for motion sensor attachment and impact. Attach the motion sensor? For piles with diameters larger than mm, attach the accelerometer at a minimum of three locations so that an integrity evaluation near the pile head may be made for each localized section of pile. Position the apparatus for applying the impact force so that the impact is applied axially with the pile and at a distance no larger than mm from the accelerometer.
Set up the apparatus for recording, reducing, and displaying data so that it is operational and the force and velocity signals are zeroed.
If only the individual impacts are recorded, ensure that the apparatus for recording, reducing, and displaying data is capable of averaging up to 10 individual records. Record the number of impacts for a speci? Take, record, and display a series of velocity and force optional measurements. Ensure that the apparatus for recording, reducing, and displaying data is capable of determining the measurement device overload threshold.
Do not use the records of impacts that cause the measurement device to overload. Consistent records are the result of uniform impacts on sound concrete, transducer systems that are properly functioning, motion sensors that are?
If records are not repeatable, do not use the data. If the cause of poor data is not a motion sensor attachment problem but rather is found to be a transducer malfunction, repair or recalibrate it before further use. NOTE 1—It is generally recommended that all components of the apparatus for obtaining dynamic measurements and the apparatus for recording, reducing, and displaying data be calibrated if any signs of system malfunctions become apparent. Often, this method gives sufficient information for integrity evaluation.
Alternately, the pile head force can be measured as well. The combination of force and velocity may give additional information regarding the pile integrity near the pile head. For both methods, data may be evaluated in both time domain and frequency domain. In the time domain analysis PEM , base the pile integrity evaluation on relative increases and decreases of velocity after the initial impact pulse Fig.
The displayed data should include the velocity and force optional records with time, an indication of the pile length and assumed material wave speed and a representation of the shape and magnitude of the ampli? The motion during the impact event is normalized usually and is associated with the pile head.
The ampli? Apparent re? Comparison of results from several piles from the site with similar construction is recommended to assess the typical response with the same ampli? Visual interpretation may be qualitative and possibly relative to other tested piles and a matter of proper engineering judgment. The results of the analysis may include a quantitative assessment of pile integrity. Such further use and interpretation of the data is a matter of engineering judgment and experience.
Use integrity evaluation from low strain tests together with other information, including pile installation procedures and observations, soil information, loading requirements, etc.
The low strain integrity evaluation should not be used as the sole factor in establishing pile acceptance or rejection. A contingency plan should be formed that allows the engineer to possibly perform further tests or dictate pile repair or replacement prior to the integrity testing, in case a serious defect is indicated.
These limitations must be understood and taken into FIG. Integrity evaluation of a pile section below a crack that crosses the entire pile cross-sectional area or a manufactured mechanical joint is not normally possible since the impact wave likely will re?
Piles with highly variable cross sections or multiple discontinuities may be difficult to evaluate. In some cases, it may be difficult to distinguish the soil response from the pile response. The method is generally not suitable for testing steel sheet, H-section or un? If the re?
This limitation may apply to long or highly variable piles or piles in soils that exhibit relatively high friction. Piles that are rigidly connected to a footing or superstructure are sometimes tested successfully although the evaluation often may be more difficult and may be inconclusive.
Some cases involving integral superstructures, may require use of two motion measuring devices attached at two different locations along the pile shaft. Also, the test may identify minor impedance variations that may not affect the bearing capacity of the pile. For piles having minor impedance variations, the engineer should use judgement as to the acceptability of these piles considering other factors such as load redistribution to adjacent piles, load transfer to the soil above the defect, applied safety factors, and structural load requirements.
Report 7. Precision and Blas 8.
Standard Test Method for Low Strain Impact Integrity Testing of Deep Foundations
Active view current version of standard. Other Historical Standards. More D This test method is applicable to long structural elements that function in a manner similar to any deep foundation units such as driven piles, augeured piles, or drilled shafts , regardless of their method of installation provided that they are receptive to low strain impact testing.
Pile Integrity Tester (PIT)
Parallel Seismic available. Send inquiries to sales pile. The Pile Integrity Tester PIT gives peace of mind that a pile or shaft is free of major cracks and voids, prior to construction of the superstructure. It may be used on most concrete or wood foundations. The PIT may also be used to test piles integral in the structure, such as those supporting existing bridges or towers, and may assess their length. With the PIT, any form of the test is performed fast, potentially making it possible to test every pile on a job site.