PILE LOAD TEST
FOR
CIVIL WORKS
1.0 GENERAL
1.1 PURPOSE
The purpose of this procedure is to specify the method for Test Piling and Pile
loading Test which shall be carried out to interpret the followings.
1) Confirmation of pile driving depth
2) Confirmation of vertical bearing capacity of pile
3) Confirmation of lateral load capacity of the pile
4) Establishment of driving criteria (penetration Versus bearing capacity).
5) Confirmation of Pull Out load capacity of pile.
1.2 SCOPE
This procedure will be used for
1) Precast driven pile.
2) Cast-in-situ driven pile.
3) Bored cast-in-situ pile.
4) Under reamed Pile.
This procedure covers the following works.
1. Test driving
2. Pile head treatment
3. Pile loading test
4. Reporting
1.3 RELATED CODE AND STANDARD
IS CODE - 2911 Part IV (Latest Revision) Code of Practice for Design and
construction of Pile Foundations - Load test on Piles
1.4 TEST REQUIREMENTS
1. The load test shall be required to provide data regarding the load
deformation characteristics of the pile upto failure or otherwise specified
and the safe design capacity.
2. Full details of the equipment proposed to be used and the test set up shall
be submitted to Site Engineer with detailed sketches for approval. After
the test set up is complete, approval from Site Engineer shall be
obtained for the same prior to commencement of loading.
3. All measuring devices shall be tested for satisfactory performances and
accuracy at an approved institution and a certificate to that effect obtained
and submitted to Site Engineer prior to use.
4. The Test pile shall be constructed using same equipment and technique
as for the job piles.
5. A minimum time period of one week shall be allowed between the time of
installation and testing in case of a precast pile and not less than four
weeks from the time of casting in case of a cast-in-situ pile.
2.0 TEST LOCATION
Locations of testing piles shall be marked on the Plot Plan. If it is
found at work site that the given location is not suitable for test piling, then the test
piling shall be carried out at an alternative location.
3.0 ESTIMATED BEARING CAPACITY
Estimated bearing capacity of piles shall be specified.
4.0 HANDLING, TRANSPORTATION AND STORAGE
In case of Precast Piles, Handling, transportation and storage shall be executed
according to specification. The cracks on the test piles shall be checked and
marked during the handling, transportation and storing and they shall be reported
to incharge engineer with illustrations and photographs, if observed.
5.0 RESPONSIBILITY
5.1 The contractor shall arrange all the required equipment and accessories for
pile load testing such as kentledge, instruments for measuring loads, deflection
etc. hydraulic jacks, pressure gauges, deflectometers etc. All these instruments be
calibrated for their accuracy from an approved laboratory and test certificates shall
be kept in the custody of the engineer prior to taking up the test in hand.
5.2 Incharge engineer shall advise or instruct the contractor regarding preparation of test
prior to commencement of pile load test work.
5.3 Contractor shall prepare and submit all necessary records for reviewing and
tests for obtaining the clearance from inspector for pile load test with information to
client, if required.
5.4 All load tests shall be made under the supervision of the engineer incharge.
6.0 TEST PILING
6.1 PILE SPECIFICATION
- Concrete grade shall be as specified in the specifications.
- The main reinforcement shall be hot rolled deformed bars grade 415 as
per IS1786 and secondary reinforcement can be mild steel bars grade
250 as per IS432.
- Concrete covering shall be not less than 40mm.
6.2 SETTING OUT
Setting out of test piling location shall be carried out by the contractor
from the survey pillars as indicated by engineer.
6.3 DRIVING OF TEST PILES
1) Pile driving depth shall be terminated on the following criteria.
a) For driven piles.
In case the dynamic formula shows more than allowable capacity, pile shall
be stopped at proposed depth. In case the formula shows less, pile shall be
driven to a depth where the dynamic formula shows more than the
allowable.
b) For cast-in-situ piles.
Pile shall be stopped on visual inspection of a sample collected from
founding level of pile.
2) Pile driving machine shall be of diesel hammer / hydraulic hammer.
3) All driving data shall be reported to site engineer next day after completion
of each test pile.
4) If any crack on pile or damage is observed during the Test Piling, the contractor shall stop the driving and shall ask the instruction of site engineer. Crack or damage shall be recorded with illustration and
photograph and be reported to engineer incharge next day.
6.4 DYNAMIC PILE DRIVING FORMULA
Pile bearing capacity shall be obtained from the formula of Hiley.
7.0 PILE HEAD TREATMENT
After the completion of test pile, pile head of each test pile shall be treated for pile
Loading Test as
1 The height of pile shall be determined not to interfere with assembling of
testing equipment. The height may be about G.L. ± 500mm.
2 Pile head shall be so treated as not to cause partial breakage and/or
deformation which affect testing.
3 Pile head to be chipped to natural plane till sound concrete is met and a
cap to be cast over the pile head for resting of jack.
8.0 TYPES OF TEST
There are 2 types of test for each type of loading namely the Initial Test and the
Routine Test.
The number of Initial Test may be one or more depending upon the number of
piles required and the importance of structure. The Initial Test shall be carried out
min. 2 or 2.5 times the estimated safe load and up to the pile destruction.
The number of Routine Test may be 1.5% of the total number of piles required.
The number of test may be increased to 2% in a particular case depending upon
the nature, type of structure and strata conditions. The Routine Test shall be
carried out to 1.5 times the estimated safe load.
9.0 PILE LOADING TEST
Load Test shall be performed when concrete has reached its required strength i.e.
28 days strength. There are mainly 3 types of loading test carried out on pile.
1) Vertical / Axial Load Test (Compression)
2) Lateral Load Test
3) Pull Out Test
9.1 VERTICAL / AXIAL LOAD TEST (COMPRESSION)
Load Test shall be performed when concrete has reached its required strength i.e.
28 days strength. The axial compressive loads test should be done as per IS code
2911 part IV (latest revision).
9.1.1 Testing Procedure
The contractor shall design the test beams, cross beams, weight, etc.
and submit them to site engineer for his approval.
Pile Loading Test shall be performed by applying compression load to the pile top
by means of a hydraulic jack against rolled steel joist (RSJ) or suitable frame
capable of providing reaction and the settlement shall be recorded by suitably
positioned dial gauges. The Kentledge consisting of RSJ or frame capable of
providing reaction shall be used. The dead weight to be applied shall be 25% more
than the maximum jacking force required. The C.G. of kentledge should be on the
axis of the pile and the load applied by the jack should be co-axial with the pile.
The dial gauges shall be positioned at equal distances around the piles and
normally held by datum bars resting on immovable supports at least 5D (subject to
a min. of 1.5m) away from the test piles periphery where D is the pile stem
diameter of circular pile or diameter of the circumscribing circle in case of square
pile.
Settlement shall be recorded with preferably 3 dial gauges of 0.01/ 0.02mm
sensitivity for single pile and 4 gauges for group.
9.1.2 Test Load
Unless failure occurs first, test pile shall be loaded at a successive incremental
load of 20% of the design load.
As explained in clause 8.0, unless failure occurs first, test pile shall be loaded up to
200% ~ 250% of the design load (Initial Test) and 150% of the design load
(Routine Test) Loading sequence in percentage of design load shall be as follows.
Cycle 1 0% ∧ 20% ∧ 40% ∧ 60% ∧
(Routine Test) 80% ∧ 100% ∧ 120% ∧ 140% ∧
150% ∧ 140% ∧ 120% ∧ 100% ∧
80% ∧ 60% ∧ 40% ∧ 20% ∧
0%
Cycle 2 0% ∧ 20% ∧ 40% ∧ 60% ∧
(Initial Test) 80% ∧ 100% ∧ 120% ∧ 140% ∧
160% ∧ 180% ∧ 200% ∧ 180% ∧
160% ∧ 140% ∧ 120% ∧ 100% ∧
80% ∧ 60% ∧ 40% ∧ 20% ∧
0%
9.1.3 Duration of Load and Intervals of Measurement
1. Settlement readings shall be taken before and after the application of each
new load increment and at 2, 4, 6,8,10,15,30,60 minutes and at every 2
hours until application of the next load increment.
2. Each stage of loading in cycle 1 and cycle 2 shall be maintained till the rate
of movement of the pile top is not more than 0.1mm per 30 minutes or
0.2mm per one hour or maximum of 2 hours which ever is earlier.
3. Further loading shall then be continued as in (1.) above till one of the
following occurs;
a) Yield of soil-pile system occurs causing progressive settlement of the
pile exceeding a value of one tenth (1/10) of the pile diameter.
b) The loading on the pile top equals twice the rated capacity or as
specified in the case of a separate test pile and 1.5 times the rated
capacity of the pile in case of a working pile.
4. Where yielding of the soil does not occur, the full test load shall be
maintained on the pile head for 24 hours or more if necessary and
settlement readings shall be observed for every hour during this period.
5. Unloading shall be carried out in the same steps as loading. A minimum of 1
hour shall be allowed to elapse between two successive stages of load
decrements in cycle 1 and cycle 2. The final rebound shall be recorded 24
hours after the entire test load has been removed.
9.1.4 The safe load on single pile for the Initial test should be least of the following
a) Two-third of the final load at which the total displacement attains a
value of 12mm unless otherwise required in a given case on the basis
of nature and type of structure in which case, the safe load should be
corresponding to the stated total displacement permissible.
b) 50 percent of the final load at which the total displacement equal to 10
percent of the pile diameter in case of uniform diameter piles and 7.5
percent of bulb diameter in case of under-reamed piles.
However, routine test shall be carried for a test load of at least one and half times
the working load; the maximum settlement of test loading in position being not
exceeding 12 mm.
9.2 LATERAL LOAD
Load Test shall be performed when concrete has reached its required strength i.e.
28 days strength. The Pile head to be chipped off upto 300mm above Cut-off-
Level. The test to be conducted at cut-off level. The lateral loads test should be
done as per IS2911 Part IV 1985.
9.2.1 Testing Procedure
Pile Loading Test shall be performed in conformity with IS 2911 Part IV. The test
may be carried out by the contractor by introducing a hydraulic jack of
adequate capacity with pressure gauge abutting the pile horizontally and reacting
against a suitable system. The reaction shall be suitably obtained from the
adjacent pile if it is conducted by jack located between two piles. The full load
imposed by the jack shall be taken as the lateral resistance of each pile. Lateral
load applied on the pile shall be measured by a calibrated pressure gauge
mounted on the jack and supported by the datum bar arrangement.
9.2.2 Test Load
Unless failure occurs first, test pile shall be loaded at a successive incremental
load of 20% of the design load.
As explained in clause 8.0, unless failure occurs first, test pile shall be loaded up to
200% of the design load (Initial Test) and 150% of the design load (Routine Test)
Loading sequence in percentage of design load shall be as follows.
Cycle 1 0% ∧ 20% ∧ 40% ∧ 60% ∧
(Routine Test) 80% ∧ 100% ∧ 120% ∧ 140% ∧
150% ∧ 140% ∧ 120% ∧ 100% ∧
80% ∧ 60% ∧ 40% ∧ 20% ∧
0%
Cycle 2 0% ∧ 20% ∧ 40% ∧ 60% ∧
(Initial Test) 80% ∧ 100% ∧ 120% ∧ 140% ∧
160% ∧ 180% ∧ 200% ∧ 180% ∧
160% ∧ 140% ∧ 120% ∧ 100% ∧
80% ∧ 60% ∧ 40% ∧ 20% ∧
0%
The maximum test load shall be observed to the total displacement increased to
12 mm
9.2.3 Duration of Load and Intervals of Measurement
1. The loading should be applied in increments of about 20 percent of the
estimated safe load.
2. The next increment should be applied after the rate of displacement is
nearer to 0.1mm per 30 minutes or 0.1mm per hour or 2 hours which ever is
later. The deflection is at the cut-off level of the pile.
3. Displacements shall be read by using at least two dial gauges, fixed to datum
bars and having least count of 0.01 mm sensitivity spaced at 30 cm and kept
horizontally one above the other on the test pile. The datum bars shall be
provided with rigid supports of steel sections, embedded well into the ground.
The supports shall be located more than 3 times the diameter of pile. The
dial gauge to be fitted on the pile surface by chipping off concrete on the side
of pile and fix a piece of glass 25mm square. The dial tips shall rest on the
central position of the glass plate.
4. Loading shall be continued till one of the following occurs :
a) Deflection of the pile head exceeds 12 mm.
b) The applied load on the pile is twice the assumed lateral load capacity
of the pile in case of a separate test pile and 1.5 times the rated
capacity in the case of working pile.
9.2.4 The safe lateral load on the pile shall be taken as the least of the following :
a) Fifty percent of the final load at which the total displacement increases to
12 mm;
b) Final load at which the total displacement corresponds to 5 mm
Note : The deflection is at cut-off level of the pile.
9.3 PULL OUT TEST
Load Test shall be performed when concrete has reached its required strength i.e.
28 days strength The axial pull out load test should be done as per IS code 2911
part IV ( latest revision ).
9.3.1 Testing Procedure
Pile Loading Test shall be performed in conformity with IS2911 Part IV.(latest
revision). The contractor shall design the test beams, cross beams,
weight, etc. and submit them to site engineer for his approval.
Pile head to be chipped to natural plane till sound concrete is met and a cap to be
cast over the pile head for resting of Jack. One rolled steel joist (R.S.J.) to rest
over jack which shall be kept on pile cap. The two ends on R.S.J. shall rest either
on ground, for good and sound soil or concrete block or two numbers dummy piles
to be cast at a minimum distance of 2.5 times the diameter of pile. The jack reacts
against the R.S.J. frame attached to the top of pile cap such that when the Jack is
operated, the pile gets pulled up and the reactions is transferred to the ground
through Soil/ Concrete Blocks/Dummy Piles. The frame work can be attached to
the pile top with the reinforcement bars which may be threaded or to which
threaded bolt may be welded.
Load applied by jack shall be measured by a calibrated pressure gauge.
Movement of the pile shall be measured by dial gauges, fixed to datum bar and
having least count of 0.01 mm, a minimum of two dial gauges, placed diametrically
opposite shall be used. Datum bars shall be provided with rigid supports.
9.3.2 Test Load
Unless failure occurs first, test pile shall be loaded at a successive incremental
load of 20% of the design load.
As explained in clause 8.0, unless failure occurs first, test pile shall be loaded up to
200% of the design load (Initial Test). Loading sequence in percentage of design
load shall be as follows.
Cycle 2 0% ∧ 20% ∧ 40% ∧ 60% ∧
(Initial Test) 80% ∧ 100% ∧ 120% ∧ 140% ∧
160% ∧ 180% ∧ 200% ∧ 180% ∧
160% ∧ 140% ∧ 120% ∧ 100% ∧
80% ∧ 60% ∧ 40% ∧ 20% ∧
0%
9.3.3 Duration of Load and Intervals of Measurement.
The pull out load increments and consequent displacement reading shall be read
as in the case of vertical load test.
9.3.4 The safe load on single pile for the Initial test should be least of the following
a) Two-third of the final load at which the total displacement attains a value
of 12mm or the load corresponding to a specified permissible uplift.
b) Half of the load at which the load displacement curve shows a clear break
(downward trend).
9.4 COMBINED VERTICAL AND LATERAL LOADING
9.4.1 Equipment and Test Set-up
The equipment and test set up shall be same as Clause 9.2.1. In addition a
platform shall be constructed on the pile top and loaded to 1.0 times the pile
capacity in vertical loading.
The pile shall be first subjected to the full vertical load. The lateral load shall
commence after all settlements due to the vertical load have ceased and while the
full vertical load is in position.
9.4.2 Test Load
The loading system, measuring system and recording of results shall be same as
described in Clause 9.2
10.0 TEST RESULT
The test result shall comprise of the following :
1. Tabulation of test data; load and movement of test pile head, reference
beam and reaction piles.
2. Load-Settlement curve
3. Time-Load curve
4. Limit Load Analysis (if pile has failed within maximum test load)
5. Conclusion
11.0 REPORTING
Measured data shall be reported in the manner submitted to site engineer within
3 days after completion of each pile Loading Test.
