Pile foundations are required for large structures. Different pile types can be installed using various equipment, even in layered soils, making safe and economical installation difficult. Dynamic pile load testing methods like low-strain integrity testing and high-strain load testing provide alternatives to static pile load testing by being more economical and efficient while still providing pile capacity and integrity information. Dynamic testing has been used successfully on numerous infrastructure projects to test piles efficiently and help reduce costs and schedule.

2. Pile are required for buildings, bridges, towers,
dams and other massive structures. A variety of pile
types can be installed by different driving
equipment in all types and even in layered soils
makes establishing a safe but economical
installation difficult.

3.  Static Pile Load Testing
 Dynamic Pile Load Testing
 Statnamic Pile Load Testing

5.  More Economical
 Less Time Consuming
 More Efficient
 Alternative for Static Pile Load Test for
Offshore piles
 Less logistics involved
 Provide more information regarding a
pile when compared to a static load test

6.  Low Strain Dynamic Testing
 High Strain Dynamic Testing

7. Low Strain Pile Integrity Testing is a quick
and cost effective method to
evaluate the shaft integrity of
concrete piles. The testing is able to
provide information on:
 pile continuity
 consistency of material
 location of defect
 degree of defect
The test method is performed with a hand
held hammer, a sensitive
accelerometer and the Pile Integrity
Tester.

8.  High strain dynamic testing consists of
estimating soil resistance and its
distribution from force and velocity
measurements obtained near the top of
a foundation impacted by a hammer or
drop weight. The impact produces a
compressive wave that travels down the
shaft of the foundation.
 A pair of strain transducers obtains the
signals necessary to compute force, while
measurements from a pair of
accelerometers are integrated to yield
velocity. These sensors are connected to
a PDA that records, processes and
displays data and results.

9. Specifications For High Strain Pile
Load Testing:
PART ONE: GENERAL
 It involves attaching strain gauges and
accelerometers to the pile near the pile
head during driving
 It shall be performed on required number of
indicator piles
 Dynamic Testing shall be performed on
production piles as chosen by the engineer
to monitor hammer and driving system
performance

10.  PART TWO - Material
 Impact Force
Application
Force or Strain
Transducer
Acceleration or
Displacement
Transducer
Signal Transmission
Cables
PDA (Model Pak, PAX or
PAL) to record, display
and analysis data

11.  PART THREE – EXECUTION:
Its mandatory that both the accelerometer and strain gage are
fixed parallel to the pile axis at a predetermined distance from the
pile top. When two sets of gages are used, they shall be
diametrically opposite

12.  High Strain Pile Load Testing Preparation: The transducers’
strain gauges and accelerometers are fixed on the pile after
performing the initial calibrations checks on them. These are fixed
either by bolting or welding. Setup the apparatus required for data
recording, reducing and displaying data.
Calibrations of the Strain gauges and Accelerometers & Fixing of
gauges.

13.  Preconstruction Wave Equation Analyses
› Dynamic Testing Consultant shall propose driving system to
install the pile to the required capacity and desired
penetration depth within the allowable driving stresses, with
prior information got by Contractor.
› In case of Bored piles, design weight, drop height and
cushion of the hammer apparatus shall be proposed.
› Proposed Driving System by the engineer shall be based
upon the wave equation analysis.
› A new pile driving system shall be proposed by the
contractor if the pile installation stresses calculated exceed
the maximum values specified by the engineer.
 Indicator Pile Program:
› Indicator piles shall be driven based upon the preliminary
driving resistance indicated by wave equation results.
› Based on the results, the engineer shall select number of
indicator piles to be statically load tested.

14.  Production Pile Testing
› Dynamic Pile Testing shall be performed on piles
during initial driving, restrike driving , initial and
restrike driving.
› Engineer may request additional piles to be
dynamically tested if hammer is modified or
replaced or any other piling behaviour
different from the normal installation procedure.
PART THREE – Reports:
› CAPWAP analyses of the dynamic pile testing data shall
be performed on data obtained from the end of initial
driving and beginning of restrike indicator piles
› Upon completion of various testing phases, the Dynamic
Testing Consultant shall prepare a formal report
summarizing the dynamic testing results.

15. Advantages:
For caissons and drilled shafts, it provides a less expensive
alternative to static load testing.
For driven piles, testing can be done during installation
and/or re-strike very economically.
Dynamic pile monitoring has the advantage of providing
immediate results that the engineer can use, including
estimates of capacity, driving stresses, and pile integrity.
Low strain dynamic testing method is a quick, convenient
way to check deep foundations for defects.
Low strain dynamic testing can be used on concrete piles,
drilled caissons, augered cast-in-place piles, concrete filled
pipe piles, and timber piles of moderate slenderness.
It is possible to check numerous piles on site during a single
day.

16.  Transducers PDA system:
› Compact, reliable, water resistant, combined
acceleration/strain transducers, cables and connectors.
› Mounting jig to increase transducer life and for protection
› Junction box for easy mounting and storage of transducer
cables
 Signal Conditioning PDA
› Maximum reliability
› Full digital signal processing
› Battery and AC powered
› No. of files digital signals only limited by hard disk capacity
› Test Box to test system functions.
 Software Environment PDA
› Windows based environment
› Easy Installation
› Higher quality signal processing

17.  Proven worldwide application now
 Uses available or easy-to-make drop hammers and
minimal pile preparation
 Confirms capacity, even at large loads
 Reduced testing time and large cost savings (cost
10 to 30 times less than static cost)
 PDA with CAPWAP evaluates capacity at low cost
for driven piles, drilled shafts,& augercast piles
 PDA gives extra valuable information (integrity,
stresses, hammer energy)
 PDA potentially saves time or pile length in
favorable site conditions
 Improves quality control by more pile tests

18.  Site specific input factors, such as damping, rapid
pore pressure cant be obtained by PDA testing.
 An experienced Geotechnical engineer or PDA
operator is needed to go through the PDA analysis
to avoid misinterpretation of the results obtained.

19. Normal Force Velocity v/s Double Impact Curve
Sometimes hammer components, cushions, helmet and pile may produce a
“Double Impact” effect in the measured test records. This may be due to
development of the hammer system impacting event and/or frequencies in the
multi-degrees of freedom driving system. Though this feature has no effect on
the quality of the data and doesn’t require special attention in data analysis.

20. Dynamic Pile driving stresses, especially
in tension, produce micro-cracks in
concrete piles. Fig A shows test records
with normal characteristics. While Fig B
contain the features indicating the
development of tension cracks along the
pile length. This is shown by an elongated
wave reflection from pile toe at 2L/c time.
The records can be evaluated in real-time
driving to monitor pile structural integrity.

21.  MSRDC 55 Flyover Scheme :
Dynamic Pile Testing was extensively used for the above flyovers in
Mumbai after conducting many co-relation studies between static &
dynamic tests to prove the reliability of High Strain Dynamic Testing.
This resulted in significant savings in time and early completion of
many flyover projects thus helping the contractors and clients. Further
the problem of space availability, which for flyovers in middle of the
road was solved resulting in greater working space and more work
efficiency for the contractors. Testing was conducted on piles ranging
from 600mm to 1200mm piles and capacity ranging from 180 tons to
1375 tons.
 Delhi Metro Project :
Dynamic Pile Testing is being extensively used for Delhi Metro Project
where it was used to ascertain capacity of many suspect piles.
Numerous co-relation studies were conducted to evaluate the test
method & acceptability of the test agency. The results were
successful and more than 30 tests have been conducted till date.
Testing was conducted on 1500mm piles with test loads upto 675 tons.

22.  Baroda Ahmedabad Expressway Project :
NHAI located 128 piles of 500mm that were abandoned by the
previous contractor more than 10 years back. No technical data like
pile depth or capacity was available. A combination of dynamic
and pile integrity tests was used on the project site. Initially PIT
conducted on the piles reported pile lengths about 20m. Borehole
taken adjacent to two such typical piles confirmed the findings.
Dynamic testing on the pile helped establish its design load. Static
test was also conducted by the client on the pile dynamically tested
for further confirmation. The static and dynamic test results matched
well helping the client save lot of time and money, since most of the
piles could be used in further construction at no additional cost.
 GCPTCL Jetty at Dahej :
Dynamic Pile Testing was adopted at one of the longest jetty in
Gujarat after co-relation with static testing on a land pile.
Conventional testing on this jetty would have been extremely
difficult, time consuming and expensive. Replacement of static
testing by dynamic testing significantly helped in early completion
of the project.