D4945 - 17 4.08 High-Strain Dynamic Testing of Piles (PDA Test)
D4945 - 17 4.08 High-Strain Dynamic Testing of Piles (PDA Test)
D4945 - 17 4.08 High-Strain Dynamic Testing of Piles (PDA Test)
for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D4945 − 17
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D653 Terminology Relating to Soil, Rock, and Contained 3.2.4.1 Discussion—Deep foundation impedance can be
Fluids estimated by multiplying the cross-sectional area by the
D1143/D1143M Test Methods for Deep Foundations Under dynamic modulus of elasticity and dividing the product by the
Static Axial Compressive Load wave speed. Alternatively, the impedance can be estimated by
D3689 Test Methods for Deep Foundations Under Static multiplying the mass density by the wave speed and cross-
Axial Tensile Load sectional area.
D3740 Practice for Minimum Requirements for Agencies Z 5 ~ EA/c ! 5 ρcA (1)
Engaged in Testing and/or Inspection of Soil and Rock as
Used in Engineering Design and Construction where:
D6026 Practice for Using Significant Digits in Geotechnical Z = impedance,
Data E = dynamic modulus of elasticity,
A = pile cross-sectional area,
3. Terminology c = wave speed, and
ρ = mass density.
3.1 Definitions:
3.1.1 For definitions of common technical terms in this 3.2.5 driven pile, n—a deep foundation unit made of pre-
standard, refer to Terminology D653. formed material with a predetermined shape and size and
typically installed by impact hammering, vibrating, or pushing.
3.2 Definitions of Terms Specific to This Standard:
3.2.6 follower, n—a structural section placed between the
3.2.1 cast in-place pile, n—a deep foundation unit made of
impact device and the deep foundation during installation or
cement grout or concrete and constructed in its final location,
testing.
for example, drilled shafts, bored piles, caissons, auger cast
piles, pressure-injected footings, etc. 3.2.7 hammer cushion, n—the material inserted between the
hammer striker plate and the helmet on top of the deep
3.2.2 deep foundation, n—a relatively slender structural
foundation.
element that transmits some or all of the load it supports to the
soil or rock well below the ground surface, that is, a driven 3.2.8 impact event, n—the period of time during which the
pile, a cast-in-place pile, or an alternate structural element deep foundation is moving due to the impact force application.
having a similar function. See Fig. 1.
3.2.3 deep foundation cushion, n—the material inserted 3.2.9 impact force, n—the transient force applied to the top
between the helmet on top of the deep foundation and the deep of the deep foundation element.
foundation (usually plywood). 3.2.10 mandrel, n—a stiff structural member placed inside a
3.2.4 deep foundation impedance, n—a measure of the deep thin shell to allow impact installation of the thin section shell.
foundation’s resistance to motion when subjected to an impact 3.2.11 moment of impact, n—the first time after the start of
event. the impact event when the acceleration is zero. See Fig. 1.
FIG. 1 Typical Force and Velocity Traces Generated by the Apparatus for Obtaining Dynamic Measurements
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3.2.12 particle velocity, n—the instantaneous velocity of a the results of a high-strain dynamic test to estimate the ultimate
particle in the deep foundation as a strain wave passes by. axial static compression capacity (see Note 1). Factors that
3.2.13 restrike, n or v—the redriving of a previously driven may affect the axial static capacity estimated from dynamic
pile, typically after a waiting period of 15 min to 30 days or tests include, but are not limited to the:
more, to assess changes in ultimate axial compressive static (1) pile installation equipment and procedures,
capacity during the time elapsed after the initial installation. (2) elapsed time since initial installation,
(3) pile material properties and dimensions,
3.2.14 wave speed, n—the speed with which a strain wave
(4) type, density, strength, stratification, and saturation of
propagates through a deep foundation.
the soil, or rock, or both adjacent to and beneath the pile,
3.2.14.1 Discussion—The wave speed is a property of the
(5) quality or type of dynamic test data,
deep foundation composition and for one-dimensional wave
(6) foundation settlement,
propagation is equal to the square root of the quotient of the
(7) analysis method, and
Modulus of Elasticity divided by mass density: c = (E/ρ)1/2. For
(8) engineering judgment and experience.
wood and concrete piles, the wave speed is the average wave
If the Engineer does not have adequate previous experience
speed over the pile length.
with these factors, and with the analysis of dynamic test data,
4. Significance and Use then a static load test carried out according to Test Method
D1143/D1143M should be used to verify estimates of static
4.1 This test method obtains the force and velocity induced capacity and its distribution along the pile length. Test Method
in a pile during an axial impact event (see Figs. 1 and 2). Force D1143/D1143M provides a direct and more reliable measure-
and velocity are typically derived from measured strain and ment of static capacity.
acceleration. The Engineer may analyze the acquired data NOTE 1—The analysis of a dynamic test will under predict the ultimate
using engineering principles and judgment to evaluate the axial static compression capacity if the pile movement during the impact
integrity of the pile, the performance of the impact system, and event is too small. The Engineer should determine how the size and shape
the maximum compressive and tensile stresses occurring in the of the pile, and the properties of the soil or rock beneath and adjacent to
the pile, affect the amount of movement required to fully mobilize the
pile. static capacity. A permanent net penetration of as little as 2 mm per impact
4.2 If sufficient axial movement occurs during the impact may indicate that sufficient movement has occurred during the impact
event, and after assessing the resulting dynamic soil response event to fully mobilize the capacity. However, high displacement driven
piles may require greater movement to avoid under predicting the static
along the side and bottom of the pile, the Engineer may analyze capacity, and cast-in-place piles often require a larger cumulative perma-
nent net penetration for a series of test blows to fully mobilize the
capacity. Static capacity may also decrease or increase over time after the
pile installation, and both static and dynamic tests represent the capacity
at the time of the respective test. Correlations between measured ultimate
axial static compression capacity and dynamic test estimates generally
improve when using dynamic restrike tests that account for soil strength
changes with time (see 6.8).
NOTE 2—Although interpretation of the dynamic test analysis may
provide an estimate of the pile’s tension (uplift) capacity, users of this
standard are cautioned to interpret conservatively the side resistance
estimated from analysis of a single dynamic measurement location, and to
avoid tension capacity estimates altogether for piles with less than 10 m
embedded length. (Additional transducers embedded near the pile toe may
also help improve tension capacity estimates.) If the Engineer does not
have adequate previous experience for the specific site and pile type with
the analysis of dynamic test data for tension capacity, then a static load test
carried out according to Test Method D3689 should be used to verify
tension capacity estimates. Test Method D3689 provides a direct and more
reliable measurement of static tension capacity.
NOTE 3—The quality of the result produced by this test method is
dependent on the competence of the personnel performing it, and the
suitability of the equipment and facilities used. Agencies that meet the
criteria of Practice D3740 are generally considered capable of competent
and objective testing/sampling/inspection/etc. Users of this test method
are cautioned that compliance with Practice D3740 does not in itself
assure reliable results. Reliable results depend on many factors; Practice
D3740 provides a means of evaluating some of those factors.
5. Apparatus
5.1 Impact Device—A high-strain dynamic test measures
the pile response to an impact force applied at the pile head and
in concentric alignment with its long axis (see Figs. 2 and 3).
The device used to apply the impact force should provide
FIG. 2 Typical Arrangement for High-Strain Dynamic Testing of a sufficient energy to cause pile penetration during the impact
Deep Foundation event adequate to mobilize the desired capacity, generally
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type of transducer at a measurement location that will not
penetrate the ground using bolts, screws, glue, solder, welds, or
similar attachment.
5.2.2 Embedded Transducers—Position the embedded
transducers at each measurement location prior to placing the
pile concrete, firmly supported by the pile reinforcement or
formwork to maintain the transducer location and orientation
during the concrete placement. When located near the pile
head, one of each type of embedded transducer located at the
centroid of the pile cross-section should provide adequate
measurement accuracy, which may be checked by proportion-
ality (see 6.9). Embedded transducers installed along the pile
length and near the pile toe help define the distribution of the
dynamic load within the pile, but usually require data quality
checks other than proportionality, such as redundant transduc-
ers (see 6.9). Embedded transducers shall provide firm anchor-
age to the pile concrete to obtain accurate measurements; the
anchorage and sensors should not significantly change the pile
impedance.
5.2.3 Transducer Accuracy—The transducers shall be cali-
brated prior to installation or mounting to an accuracy of 3 %
throughout the applicable measurement range. If damaged or
functioning improperly, the transducers shall be replaced,
repaired and recalibrated, or rejected. The design of
transducers, whether mounted or embedded as single units or
as a combined unit, shall maintain the accuracy of, and prevent
interference between, the individual measurements. In general,
NOTE 1—Strain transducer and accelerometer may be combined into avoid mounting or embedding acceleration, velocity, or dis-
one unit on each side of the deep foundation. placement transducers so that they bear directly on the force or
FIG. 3 Schematic Diagram of Apparatus for Dynamic Monitoring strain transducers, and place all transducers so that they have
of Deep Foundations immediate contact with the pile material.
5.2.4 Transducers to Obtain the Force Data:
5.2.4.1 Strain Transducers—The strain transducers shall
include compensation for temperature effects, and shall have
producing a maximum impact force of the same order of linear output over the full operating range (typically between
magnitude, or greater than, the ultimate pile capacity (static –2000 and +2000 microstrain plus an additional allowance for
plus dynamic). The Engineer may approve a conventional pile possible strain induced by mounting on a rough surface).
driving hammer, drop weight, or similar impact device based Attachment points shall be spaced (dimensions S and H in
on predictive dynamic analysis, experience, or both. The Figs. 4-7) no less than 50 mm and no more than 100 mm apart.
impact shall not result in dynamic stresses that will damage the When attached to the pile, their natural frequency shall be in
pile, typically less than the yield strength of the pile material excess of 2000 Hz.
after reduction for potential bending and non-uniform stresses
5.2.4.2 Force Transducers—As an alternate to strain
(commonly 90 % of yield for steel and 85 % for concrete). The
transducers, axial force measurements can be made by force
Engineer may require cushions, variable control of the impact
transducers placed between the pile head and the impact
energy (drop height, stroke, fuel settings, hydraulic pressure,
device, or affixed in the pile cross-section, although such
etc.), or both to prevent excessive compressive and tensile
transducers may alter the dynamic characteristics of the driving
stress in the pile during all phases of pile testing. In case of a
system, the dynamic pile response, or both. Force transducers
drop mass, the weight of the mass should be at least 1 to 2 %
shall have impedance between 50 and 200 % of the pile
of the desired ultimate test capacity.
impedance. The output signal shall be linearly proportional to
5.2 Dynamic Measurements—The dynamic measurement the axial force, even under eccentric load application. The
apparatus shall include transducers mounted externally on the connection between the force transducers and the deep foun-
pile surface, or embedded within a concrete pile, that are dation shall have the smallest possible mass and least possible
capable of independently measuring strain and acceleration cushion necessary to prevent damage.
versus time during the impact event at a minimum of one 5.2.5 Transducers to Obtain the Velocity Data:
specific location along the pile length as described in 5.2.7. 5.2.5.1 Acceleration Transducers (or Accelerometers): Ve-
5.2.1 External Transducers—For externally mounted locity data shall be obtained by using the dynamic measure-
transducers, remove any unsound or deleterious material from ment apparatus to integrate the acceleration signals from
the pile surface and firmly attach a minimum of two of each of accelerometers. The accelerometers shall be directly attached
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NOTE 1—Shown as separate transducers or alternative combined NOTE 1—Shown as separate transducers.
transducers. FIG. 5 Typical Arrangement for Attaching Transducers to Con-
FIG. 4 Typical Arrangement for Attaching Transducers to Pipe crete Piles
Piles
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velocity between impact events and shall adjust the velocity 6.3 Determination of Mass Density of Deep Foundations—
record to account for transducer zero drift during the impact The density of each wood pile shall be determined from the
event. total weight of the pile, or a sample of the pile, the correspond-
5.4.3.3 Signal Conditioning—The signal conditioning for ing volume, and the gravitational constant. The density of
force and velocity shall have equal frequency response curves concrete or grout can be measured in a similar manner.
to avoid relative phase shifts and relative amplitude differences Alternately, the density of concrete piles is often assumed to be
and retain all frequency components in the data below at least 2450 kg/m3 and the density of grout used for auger-cast or
2000 Hz. similar types of piles is often assumed to be 2150 kg/m3. The
5.4.4 Display of Data—For each impact event, the raw or mass density of structural steel piles can be assumed as 7850
processed signals from the transducers specified in 5.2 shall be kg/m3. The mass density of composite deep foundations, such
displayed during data acquisition or replay as a function of as concrete filled steel pipes, can be computed from a weighted
time, such as on a digital graphics display. average of the areas of the materials at each differing cross-
5.4.5 Field Supervision—A qualified engineer shall directly section. Assumed and computed values of mass density should
supervise all field testing and assess data quality and reliability be verified directly if possible, or indirectly through their effect
for later detailed evaluation (see 6.9). Alternatively, field on impedance and proportionality (see 6.9).
personnel may transmit the data concurrently as acquired to a 6.4 Determination of Dynamic Modulus of Elasticity of
qualified engineer supervising the testing from a remote Deep Foundations—The dynamic modulus of elasticity (E) for
location. concrete, wood, steel, or composite piles can be computed as
6. Procedure the product of the square of the wave speed (determined as
indicated in 6.2) times the mass density (E = ρc2). The dynamic
6.1 General—Allow sufficient time for driven and cast-in-
modulus of elasticity may be assumed as 207 × 106 kPa for
place deep foundations constructed of concrete to gain ad-
structural steel. Assumed and computed values of the dynamic
equate structural strength prior to testing. Record applicable
modulus of elasticity should be verified directly if possible, or
project information (Section 7). Attach the transducers (Section
indirectly through their effect on impedance and proportional-
5) to the deep foundation, perform any calibration checks
ity (see 6.9).
recommended by the equipment manufacturer, and take the
NOTE 5—Alternatively, the static modulus of elasticity for concrete
dynamic measurements for the impacts during the interval to piles and wood piles may be determined from measurements made during
be monitored together with routine observations of number of a compression test performed in accordance with Test Methods C469 or
blows per unit penetration (“blow count”) or set per blow. D198 respectively. The Engineer should then estimate the dynamic
Determine the response of a driven pile to the high-strain modulus (typically assumed 10 % greater) from this measurement.
dynamic test from a minimum of ten impact records during 6.5 Preparation—Mark the pile clearly at appropriate unit
initial driving and, when used for soil resistance computations, intervals to prepare for recording blow counts. Attach the
normally from one or two representative blows at the begin- transducers as described in Section 5. Determine the pile wave
ning of a restrike. In case of cast-in-place pile, determine the speed (see 6.2) and density (see 6.3). For concrete piles or
response from one or two representative blows from the test. concrete filled pipe piles, place a pile cushion made of plywood
NOTE 4—Warning—Never approach a deep foundation being tested or other material with similar stiffness on top of the pile. For
while the hammer or large drop weight is operating as materials or concrete filled pipe piles, the concrete must completely fill the
appurtenances may break free and jeopardize the safety of persons in the pile top so that the impact is transferred through the pile
vicinity. Preferably the contractor crew will attach the transducers to the cushion to the concrete. Position the impact device on the pile
pile.
head to apply the impact force concentric with the long axis of
6.2 Determination of Wave Speed for Deep Foundations— the pile. Prepare the apparatus for recording, processing, and
The wave speed of concrete or wood piles should preferably be displaying data to receive the dynamic measurements and
determined from an early impact event if a tensile reflection balance the strain (or force) and acceleration signals to their
from the pile toe is clearly identified. Divide two times the respective reference levels (for example, zero).
length of pile below transducers by the observed time between
start of the impact (for example, initial sharp rise of the signal) 6.6 Recording Hammer Information—Record the mass of
and the start of the tensile reflection (for example, later relative the hammer ram or drop weight. For drop hammers and single
velocity increase) to obtain the wave speed. For piles with acting diesel and air/steam/hydraulic hammers, record the drop
instrumentation at both the head and near the toe, the wave height of the ram or the ram travel length. For double acting
speed can be calculated from dividing the distance between diesel hammers, measure the bounce pressure, and for double
these locations by the time between impact arrivals at these acting steam or compressed air hammers, measure the steam or
locations. The wave speed of steel piles can be assumed as air pressure in the pressure line to the hammer. For hydraulic
5123 m/s. Assumed wave speed values should be verified hammers or any of the previously listed hammer types, record
directly or indirectly if possible. The overall wave speed the kinetic energy from the hammer readout when available.
observed during a high-strain event as described above may Record the number of impact blows per minute delivered by
differ (typically slower) from the local wave speed used to the hammer.
compute impedance because of variability in pile properties, 6.7 Taking Measurements—Take, record, and display force
degradation of pile material during repeated hammer blows, or and velocity measurements for each impact event. Compare the
splices in the pile length. force and the product of velocity and impedance at the moment
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of impact (see 6.9). Obtain the net permanent displacement per 6.10 Followers and Mandrels—If a follower is used for
impact from the pile driving blow count record, or from marks installing and testing cast-in-place concrete deep foundations,
placed on the pile prior to and after the test using the same this follower should have an impedance between 80 and 150 %
reference, directly from the displacement transducers (if used), of that of the deep foundation. However, additional caution and
or by integration of the velocity versus time record (typically analysis may be required if the impedance is not within 10 %
less reliable). Obtain the maximum energy transferred to the of that of the deep foundation and gauges are attached to the
location of the transducers from the integral over time of force follower. For mandrel-driven piles, the mandrel may be instru-
multiplied by velocity. mented in a similar way to a driven pile provided that the
mandrel is constructed of a single member with no joints.
6.8 Time of Testing—Dynamic tests performed during the
initial installation of a driven pile typically monitor the 6.11 Testing Cast-in-Place Deep Foundations—For testing
performance of the impact device, the driving stresses in the cast-in-place piles it is often advantageous to build up the top
pile, the pile integrity, and relative changes in capacity. If the of the pile to encase protruding reinforcement, to strengthen it
test results are used for static capacity computations, then for the impact using a steel shell, or to eliminate excessive
dynamic measurements should (also) be performed during excavation (sensors must be mounted at least 1.5 diameters
restrikes of the deep foundation, after waiting a period of time below the impact location). The pile top should be flat and
following the initial installation sufficient to allow pore water square to the longitudinal pile axis, and should be protected
pressure and soil strength changes to occur. (See Note 1.) with plywood cushions, or other cushion material of uniform
thickness. A thick steel plate may also be placed on top of the
6.9 Data Quality Checks—Confirm the accuracy of dynamic plywood to distribute the impact. Preferably apply a series of
measurements obtained near the pile head by periodically single impact blows using a drop mass having a weight of at
checking that the average of the measured force signals and the least 1 to 2 % of the desired ultimate test capacity, beginning
product of the impedance and the average of the measured with a low drop height to check transducer function and pile
velocity signals agree proportionally at the moment of impact. stresses and then progressing to greater drop heights to
Do not expect proportionality when reflections occur from pile mobilize additional pile capacity. For externally mounted
impedance changes nearby and below the transducers or from transducers, carefully select transducer locations having sound
soil resistance, such as for transducers near the pile bottom or, concrete, and grind or sand the pile as necessary to obtain a
depending on the rise time to the initial force peak, transducers smooth, flat, clean surface on which to mount the transducers
located between the pile head and the bottom. Reject non parallel to the pile axis. Because cast-in-place piles may have
proportional data. Two velocity signals should generally agree non uniform material properties and a variable, irregular
well at a particular measurement location, even though the two cross-section, when using externally mounted transducers con-
force signals may indicate significant bending. Two embedded sider placing four strain transducers equally spaced around the
strain measurements made in close proximity to the pile axis at perimeter and as described in 5.2.7. The average force deter-
the same location, or at adjacent locations on the pile axis, can mined from each diametrically opposed pair of transducers can
provide a consistency check of each other. For piles with a high then be compared together, and with the average velocity as in
percentage of end bearing, analysis of measurements made 6.9, to assess the data quality of all force measurements.
near the pile head may provide confirmation of measurements NOTE 7—The strength and dynamic modulus of elasticity for cast-in-
near the pile bottom. For an impact device delivering relatively place deep foundations depends on the quality and the age of concrete, and
similar impacts, the force and velocity versus time over a series can vary considerably over the cross-section and along the length of the
deep foundation. The dynamic modulus of elasticity as calculated from the
of consecutive impact events should be relatively consistent. wave speed (see 3.2) will therefore be an average value which may differ
Consistent and proportional signals of (average) force versus from the modulus at the transducer location. If the cast-in-place deep
(average) velocity times pile impedance are the result of the foundation is encased in a steel shell, then use a composite mass density
transducer systems performing properly and the apparatus for and composite dynamic modulus of elasticity.
recording, processing, and displaying data being properly
calibrated. If the signals are not consistent, or are not in 7. Report: Test Data Sheet(s)/Form(s)
proportionality agreement, investigate the cause and correct as 7.1 The methodology used to specify how data are recorded
necessary. If the cause is loose or misaligned instrumentation, on the test data sheet(s)/form(s), as given below, is covered in
then correct the problem prior to continuing the test. If the 1.6.
cause is determined to be a transducer malfunction, it must be
7.2 Record as a minimum the following general information
repaired or recalibrated, or both, before further use. If the cause
(data).
cannot be determined and rectified, then the test is to be
7.2.1 Project identification and location,
rejected. Perform self-calibration checks of the apparatus used
7.2.2 Identification of the staff involved with the testing,
for recording, processing, and displaying data periodically
7.2.3 Log(s) of nearby or typical test boring(s) or other soil
during testing as recommended by the manufacturer, and
investigation.
recalibrate before further use if found to be out of manufac-
7.2.4 Deep Foundation Installation Equipment:
turer’s tolerance.
7.2.4.1 For driven piles: description of driving methods and
NOTE 6—It is generally recommended that all components of the
apparatus for obtaining dynamic measurements and the apparatus for installation equipment used for driving piles, testing piles, or
recording, processing and displaying data be calibrated at least once every both as appropriate, for example, make, model, and type of
two years to the standards of the manufacturer. hammer, size (ram weight and stroke), manufacturer’s energy
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rating, capabilities, operating performance levels or pressures, 7.3.2 Date of test(s), sequence of testing (for example, “end
fuel settings, hammer cushion and pile cushion descriptions of driving” or “beginning of restrike”), and elapsed time since
with cushion exchange details, and description of lead type and end of initial driving for restrikes,
any special installation equipment such as a follower, mandrel, 7.3.3 Density, wave speed, and dynamic modulus of elas-
punch, pre-drill or jet. ticity of the test deep foundation, reporting each quantity with
7.2.4.2 For cast-in-place concrete piles: description of con- three significant digits, but not to exceed the precision of the
struction methods, drilling or augering equipment, and con- measurement,
crete or grout placement, for example, type of drill rig, type 7.3.4 Penetration resistance (blows per unit penetration, or
and dimensions of drill tool(s), auger(s), and cleanout tool(s), set per blow) and embedment depth,
tremie, concrete or grout pump, and casings. 7.3.5 Graphical presentation of velocity and force measure-
7.2.5 Test Pile(s): ments in the time domain for representative blows,
7.2.5.1 Identification (name and designation) of test pile(s), 7.3.6 Analysis method(s) used to interpret or evaluate test
7.2.5.2 Required ultimate axial static compressive capacity, measurements,
7.2.5.3 Type and dimensions of deep foundation(s) includ- 7.3.7 Interpretation of the test measurements, including
ing nominal or actual cross-sectional area, or both, length, wall measurements down the pile if applicable, to estimate as
thickness of pipe or casing, and diameter (as a function length appropriate the overall magnitude of the dynamic and static
for tapered or composite deep foundations), axial compressive capacity mobilized at the time of testing, the
distribution of the dynamic and static axial compressive
7.2.5.4 For driven or cast-in-place concrete piles: date(s)
capacity along the pile length, and the engineering properties
test pile constructed or cast, design and measured concrete
of the pile and the soil or rock adjacent to the pile as used in
cylinder strengths and date of test(s), density, effective
the interpretation,
prestress, and description of internal and external reinforce-
7.3.8 Comments on the performance of the impact device as
ment (type, grade, size, length, number and arrangement of
measured by the energy transferred into the deep foundation
prestress wire, longitudinal bars, lateral ties, and spiral stiffen-
with comparison to manufacturer’s rating or ram weight and
ers; casing or shell size and length),
drop height,
7.2.5.5 For steel piles: steel designation, grade, minimum 7.3.9 Comments on the driving stresses within the deep
yield strength, and type of pile (for example, seamless or spiral foundation, and whether measured or estimated through
weld pipe, H section designation), analysis,
7.2.5.6 For timber piles: length, straightness, preservative 7.3.10 Comments on the integrity of the deep foundation,
treatment, tip and butt dimensions (and area as a function of and
length), and measured density for each pile, 7.3.11 Numerical summary of measured and interpreted
7.2.5.7 Description and location of splices, special pile tip results, with statistical analysis as appropriate, reporting time
protection, and any special coatings applied if applicable, in milliseconds at the rate digitized, and other quantities with
7.2.5.8 Inclination angle from vertical, design and installed, three significant digits, but not to exceed the precision of the
and measurement.
7.2.5.9 Observations of deep foundations including spalled
areas, cracks, head surface of deep foundations. 8. Precision and Bias
7.2.6 Deep Foundation Installation: 8.1 Precision—Test data on precision is not presented due to
7.2.6.1 For cast-in-place piles, include the volume of con- the nature of this test method. It is either not feasible or too
crete or grout placed in deep foundation (volume versus depth, costly at this time to have ten or more agencies participate in
if available), and a description of installation procedures used, an in situ testing program at a given site. The inherent
such as casing installation or extraction, variability of the soil, or rock, or both surrounding the pile, the
7.2.6.2 For driven piles, include date of installation, driving pile driving apparatus, and the pile itself adversely affect the
records with blow count, and hammer stroke or operating level determination of precision.
for final unit penetration, 8.1.1 The Subcommittee D18.11 is seeking any data from
the users of this test method that might be used to make a
7.2.6.3 Elevations of the pile top, pile bottom, and ground
limited statement on precision.
surface referenced to a datum, and
7.2.6.4 Cause and duration of installation interruptions and 8.2 Bias—There is no accepted reference value for this test
notation of any unusual occurrences. method, therefore bias cannot be determined.
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SUMMARY OF CHANGES
In accordance with Committee D18 policy, this section identifies the location of changes to this standard since
the last edition (2012) that may impact the use of this standard. (Approved November 1, 2017)
(1) Added clarification statement in 1.1 to clarify that force (9) Broke 5.2.4 into subsections for clarity and re-numbered
and velocity are typically derived from strain and acceleration. accordingly.
Similar statement is added in 4.1. In the same light, wording (10) Subsection 6.1—A statement that recommends how many
was changed through the document to accommodate the blows should be analyzed for driven piles exists. A similar
concept above, for example, “calculated” was changed to statement was added for cast-in-place piles for clarity.
“estimated,” “computed” was changed to “derived,” “measured (11) Subsection 6.2—A paragraph currently existed that de-
force” was changed to “measured data” for clarification pur- scribed how to use a low strain dynamic event for the
poses. determination of wave speed when you are performing a high
(2) Added comment to 1.5 to conform to D18 Standards strain dynamic test. It is an obsolete method that nobody uses
Preparation Manual caveat of 9.4.2.4. when doing a high strain dynamic test, therefore the paragraph
(3) Replaced 1.7 with 1.6.1 to conform to D18 Standards was deleted. Moreover, the term “structural” was deleted from
Preparation Manual (3.5, and 9.7.2.2).
the phrase “structural steel piles” to avoid limiting the wave
(4) Corrected the format of statement referring to D653 in the
speed of steel piles to only the H-piles. Wave speed of 5123
“Terminology” section to conform to current D18 Standards
m/s is valid for all steel piles.
Preparation Manual.
(5) Fixed definitions to comply with ASTM formatting recom- (12) Subsection 6.10—Wording was added to emphasize chal-
mendations (that is, added the word “discussion” to accommo- lenges associated with the use of a follower.
date wordy definitions). (13) Report section revised to reflect requirements of D18.91
(6) Improved “Impact force” definition to describe what impact special memorandum on report section in test methods (format,
force is rather than describe how you estimate it. section headings).
(7) Improved “Wave Speed” definition by adding a clarifying (14) Added “identification of the staff involved with the
statement under the discussion for wood and concrete piles. testing” to the reporting requirements. Added “other soil
(8) Subsection 5.1—Added a statement under impact device to investigations” (other than soil borings) to reporting require-
describe how large the drop mass should be. This statement ments.
already existed in the standard under a different section but
here it is also added under the “impact device” section for
completeness. The phrase “to prevent excessive stresses” is
changed to “to prevent compressive and tensile stresses” for
clarification.
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