DRIVING EQUIPMENT
Hammer Size and Cushion
Block
Hammer size - The piles
shall be driven with a diesel hammer. The hammer shall develop the minimum
energy per blow to achieve the required pile capacity or an equivalent set
based upon the rated energy of the actual piling hammer used. The final set
will be adjusted as necessary after driving and testing of the test piles(s).
The set will be valid only for the hammer used to drive the test piles.
Cushion blocks – A 419
mm Aluminum-Micarta cap block shall be used. Cap blocks shall be inspected
periodically during driving and no driving shall be done with blocks that have
been unduly worn and compacted with use.
Pile cushion blocks for
all piles shall be of the same thickness, material, quality and construction.
Uneven and cover sized cushion caps shall be not allowed.
The number of blows for
the last 300 mm shall not be smaller than determined by the pile load test and
established by the Owner, and in addition, the number of blows for last 1 cm
shall not be smaller than 12.
Piles drivers with
firmly supported fixed leads extending down to the lowest point that the hammer
must reach are acceptable; short leads suspended from a line and braced only by
lines will not be acceptable unless piles are rigidly braced and held in
alignment by suitable guide frames prior to pile driving. Leads with spear
(auger) points fixed to the lower lead end, embedded in the ground adjacent to
the pile and fixed or suspended from the pile driving rig are acceptable,
provided the leads remain, stationery during pile driving.
At all stages during
driving, the pile shall be supported and restrained by means of leaders,
trestles, temporary supports or other guide arrangements to maintain position
and alignment and to prevent buckling.
The piling equipment and
driving force used shall ensure that the piles are installed without damage or
loss of strength. If, at any time, in the opinion of Owner, satisfactory
results cannot be obtained with the equipment furnished by the Contractor,
equipment of other rated capacity capable of driving piles to approved elevation,
shall be furnished and used by Contractor at no additional cost to the Owner.
MARKING
AND LENGTH OF PILES
Marking
Of Piles
Each
pile shall be clearly identified by its number in white paint at least every
three meters, with a minimum of three locations at the top, bottom and middle.
The length shall be marked and identified with white paint at least every
meter. Intervals of 300 mm shall also be marked with paint.
Length
of Piles
The
length of the piles shall be as necessary to develop the required pile
capacity. The Contractor shall determine
length of piles based on geotechnical data and shall be proven by pile load
tests.
SETTING
OUT
The main setting out for the piles is to be
completed prior to commencement of piling.
Secondary or individual pile setting out is to be completed and agreed
upon not less than 8 hours prior to commencing work on the piles
concerned. All main setting out points,
lines, stations and other work are to be maintained safe and undisturbed.
DRIVING ON PILES
Pitching and Driving
Piles shall be pitched
accurately in the position and driven to the lines shown on the approved
drawings.
Piles shall be driven
using approved pile driving equipment. Where piles have to be driven below the
level of the bottom of the leaders, extension leaders shall be fitted. The use
of a follower or dolly will not be permitted except with approval or the Owner.
Reduction
of Hammer Energy - When the point of the pile is passing through soft soil,
there is the possibility that longitudinal tensile stresses will be developed
in the pile shaft by the elastic shock waves travelling up and down the pile.
For such driving conditions, the length of stroke of hammer shall be reduced.
Contractor
shall operate hammer at all times with adequate explosion pressure to maintain
the speed and energy recommended by the manufacturer.
Jetting
of piles will not be permitted. Augering will be required to drive piles
adjacent the existing structure.
The
depth of augering shall not be exceed two-thirds of the final driven length of
the pile and shall proceed only with the approval of the Owner.
The use
of a hammer which has not been operated for three hours or more, or fresh pile
cushion material just before final penetration will not be permitted except with
approval of the Owner.
The
contractor shall ensure that damage does not occur to the piles during driving.
Protection of the pile heads and the energy per blow shall be regulated to
ensure that the piles are not overstressed during driving. Also, care shall be
used during driving to prevent and correct any tendency of piles to twist or
rotate. The tip of the pipe pile shall be stiffened by the Contractor, if
necessary, to prevent damage during driving.
All
piles shall satisfy the tolerances for position and inclination as stated
herein. The deviation in position of the as-driven centerline of a pile or the
projection of its centerline from the pile center point as shown on the
setting-out drawings the defined level. Deviations from vertical shall not be
more than 1 in 100 for vertical piles and better piles shall not deviate by
more than 2 in 100 from the specified better.
If
piles are installed out of plan position or line beyond allowable tolerances,
the piles shall be extracted or additional piles shall be driven, as requested
by the Owner, to properly provide for load conditions and to avoid
overstressing of piles. Manipulation of piles to force them into position or
line will not be permitted. The Contractor shall be responsible to extract
and/or drive additional piles as noted above at no cost to the Owner.
Damage
pile shall be abandoned, replaced or repaired as approved by the Owner at the
Contractor’s expense. Abandoned piles shall be filled with soil that no cost to
the Owner. Additional piles shall be driven as requested, to provide for load
conditions and to avoid overstressing of piles. The Contractor shall be
responsible to drive additional piles at no cost to the Owner.
Piles
shall be driven until the required length and capacity is achieved. If piles do
not achieve the required final set at the specified depth, piles shall be
driven deeper until specification is met and upper portion shall be extended by
welding.
Driving
of production piles shall not begin until the evaluation of the preliminary
pile load tests for tension load, lateral load and compression load to failure
has been completed for each diameter type of pile.
Build Up
In the
event that any pile is driven below the established out off elevation or if
pile heads are damage during driving, all necessary build up shall be provided.
Build ups shall consist of all required pipes, splices, concrete, reinforcing
steel, etc. required to bring the top of the pile to the cut off elevation.
Cost of pile build up shall be included in the Contract Price.
Pile
Heaving
After
piles have been driven, the Contractor shall check to determine if any piles
have heaved due to driving of adjacent piles and redrive piles that heaved as
directed by Owner; cost of redriving shall be included in the Contract
Price.
The
Contractor shall monitor vibration and ground movement during pile driving. A
proposal of the monitoring method shall be submitted to the Owner for approval.
PILE CUT-OFF
On
completion of the driving of the piles to the levels approved by the Owner, the
heads of all piles shall be cut off to the level indicated, of the drawing. Cut
off piles at elevations indicated, only after there is no danger from up‑heaval.
Cutting may be performed with pneumatic tools or burning with a torch or any
order method approved by the Owner. In no case shall explosives be used for
cutting. Make cuts at right angles to the vertical axis of piles. All cut-offs
shall become property of the Contractor and shall be removed by him from the
Project Site.
EXTRACTION
OF PILES
All
piles which are damages, misallocated, driven out of alignment or positioned
outside the specific tolerances shall be extracted or cut off and abandoned as
directed by the Owner. Replacement piles shall be at expense of the Contractor.
When
extraction of the piles is required, it shall be carried out using efficient
extraction equipment of adequate capacity. The extraction equipment shall be
correctly positioned over the pile to minimize damage to the pile head and to
prevent any major disturbance of the supporting ground. Pile heads damaged
during extraction and pile toes found to have been damaged during initial
driving are to be trimmed with a clean cut perpendicular to the pile exist
prior to re‑driving. Extension pieces shall be added as necessary to restore
the pile to its original length.
PILE TO PILE CAP CONNECTION
Adequate structural
connection between the piles and the pile caps shall be provided to meet
seismic loading design requirements.
RECORDS OF PILE CONSTRUCTION
During the course of the
work, the Contractor shall maintain a complete record of pile construction and
the Contractor shall submit to the Owner, in an approved format, a record for
each pile. Each pile record shall be submitted immediately after completion of
each pile and shall include:
§ Type of pile
§ Pile number and all
principal characteristics of the pile including dimensions
§ The depth and rate of
penetration, in relation to site datum, for the length of the pile
§ Details of driving and
installation sequence progress, including dates, times, equipment used and
personnel (operator, engineer, etc.)
§ The equipment hammer
model number, weight and rated energy
§ Number of hammer blows for each 300 mm of
driving/penetration
§
Actual
location of piles as driven, with variations from plan locations indicated
§
Variations
in plumbness or batter
§
Set
on completion of the initial drive and final test set on completion of the
final redrive
§
Any
unusual phenomena encountered in driving piles
§
Depth
and type of soil strata
§
Observations
of ground water level and ground water flow
§
Name
of Inspector for each pile
§
Cushion
material identification when changed, and material added
§
Top
elevation when driving is complete
§
Cutoff
Elevation
§
Depth
of augering and auger size
§
The
records of pile construction shall be submitted in accordance with the
requirement in Book II
§
For
cast-in-place concrete top piles, the following additional data :
Ø
Date
and time of “Release for Concreting”
Ø
Date
and time of placing concrete fill, including starting and completion times
Ø
Quantity
of concrete fill
PILE LOAD TESTING
SCOPE OF WORK
Work specified under this section includes
furnishing all labor, materials and equipment for completion, tension and
lateral load testing of the piles. Piles installed for testing are only
pre-production piles. Piles installed for the permanent structure are
production piles. Piles are selected for testing are test piles. All
pre-production piles and production piles specifically selected for testing are
test piles.
Drive test pile to indicated depth and/or
indicated resistance.
Keep a penetration record of test piles and
anchor piles in accordance with requirements set forth in mentioned below.
Keep a penetration record of test piles and
anchor piles in accordance with requirements set forth in mentioned before.
The pile load testing shall be carried out to
the satisfaction of the Owner.
Upon completion of the preliminary pile load
testing, Contractor shall cut off the preliminary test piles, as directed by the
Owner and dispose of the cut off portion.
METHOD OF TEST
General Test Provisions
Perform
tests to the test load indicated on the approved drawings or as specified
herein. Test equipment for the compressive load tests shall be capable of
applying the required test load. Test equipment for the lateral and tensile
load tests shall be capable of applying a test load equal to 300 % of the test
design loads shown on the approved drawings.
Care
shall be taken to ensure that the load applied by the hydraulic jack is coaxial
with the pile.
Managed
test continuously during test period. If a test is stopped before completion,
and the load is wholly or partially removed from the test pile due to improper
or insufficient loading, yield of supports or connections, malfunctioning of
measurement of measuring and testing equipment or for other mechanical reasons
or for reasons for which the Contractor is responsible, the Owner shall order
the test abandoned and replaced by a new test on another pile at an adjacent location
at no additional cost.
Prior to driving each
preliminary test pile, Contractor shall drill a borehole located between
1 and 2 meters from each test pile. The boring shall consist of continuous
sampling with Standard Penetration Test (SPT) being performed at 2.0 m
intervals in the soil for the entire length of the boring. The boring shall
penetrate with continuous sampling. A Dutch Cone penetration test shall also be
performed at each boring location.
Before commencing any test the Contractor shall submit
for approval full details of his proposals including the datum beam
arrangements and locations of supports. Working piles shall not be used as
tension reaction piles.
Sufficient number of anchor piles shall be
driven to prevent excessive movement of anchor piles. All devices for measuring
the settlement of piles shall be sheltered, and rigidly attached to a firm and
independent support driven not less than 2.5 m from the nearest point of the
test pile or anchor piles.
The calibrated load cell shall be used for the
load measurement.
Compressive Load Test
Perform
compressive load test on individual piles accordance with applicable
requirements of ASTM D1143.
Hydraulic
jack and anchored reaction member method shall be used to apply the test load.
Jacking against production piles acting in tension shall not be permitted.
Prior to
the start of production pile driving, compressive tests to failure shall be
performed on individual test pile driven for testing purposes. The location of
the test piles shall be as indicated on the drawings.
Compressive
tests shall be performed on individual production piles selected by the Owner.
The approximate location and number of the tests shall be as indicated on the
approved drawings.
Test
loads for piles tested to failure shall be applied in accordance with the
procedure for loading in excess of the standard load test, as specified in ASTM
D1143. Test load on production piles shall be applied in accordance with the
standard loading procedure, as specified in ASTM D1143. The preliminary load
tests to failure shall include the cyclical load test of ASTM D1143. Production
pile load tests shall include the cyclic load test only when indicated on the
approved drawings.
For the
preliminary compression tests, loading shall be increased as specified in ASTM
D1143 until failure or when 300 % of the test design load is reached. Loading
for the production piling tests shall be increased as specified in ASTM D1143.
Monitor
pile head deflection using a minimum of 3 dial gages, mounted to an independent
frame and located radially about the pile.
Failure
shall be defined as the load at which vertical deflection of the pile head
exceeds 50 mm.
Tensile Load Test
Perform
tensile load tests on individual piles in accordance with applicable
requirements of ASTM D3689.
Test
loads shall be applied in accordance with the procedure for loading in excess
of 200 % of pile design uplift load, as specified in ASTM D3689.
Loading
shall be increased until failure occurs.
Tension
test shall be performed on individual piles driven for testing purposes. The
location of the test piles shall be as indicated on the approved drawings.
Monitor
pile head deflection using a minimum of 3 dial gages mounted to an independent
frame and located radially about the pile head.
Failure
shall be defined as the load at which uplift continues to increase without any
further increase in load.
No
concrete shall be placed for pile caps until installation of reinforcement,
tell tales and tension connection is complete. Design of tension connection
shall be Contractor’s responsibility.
Lateral Load Test
Perform
lateral load tests on single piles in accordance with the applicable
requirements of ASTM D3966. Test shall be performed for fixed head and free
head conditions.
Test
load shall be applied in accordance with the procedure for loading in excess of
the standard load test load, with cyclic loading, as specified in ASTM D3966.
Loading
shall be increased until failure occurs. Failure shall be defined as the load
at which horizontal deflection continues to increase without any further
increase in load, or any lateral movement at design soil top elevation
exceeding 12 mm.
Lateral
load tests shall be performed on separate piles driven for testing purposes.
The location of the test piles shall be as indicated on the design approved
drawings.
Monitor
pile butt movement and rotation of the head of the test piles.
TEST EQUIPMENT AND MATERIALS
Provide all equipment and materials required for
the test and remove all such equipment and materials at the conclusion of test.
Submit
drawings of test arrangement, including full data for equipment and materials,
for review and Owner’s approval, in accordance with the requirements, in Book
II.
Test
Results: Submit test results complete with tabulation of all test data to the
Owner immediately after conclusion of test. Data shall include, as a minimum,
calibration results of all test loading equipment, all dial gauge readings at
each increment and decrement of load, time duration of test with time started
and time completed and any unusual occurrences during testing.
NUMBER OF
TESTS
Before piling works commences, preliminary pile
tests shall be carried out. At least one pile of each pile type in each
specified soil condition shall be tested.
The Owner will select the working piles to be
tested. At least one working pile for each major grouping of piles or at least
one working pile for each one hundred piles shall be tested.