GENERAL
Contractor shall furnish
all labor, material and equipment necessary to design, fabricate, deliver,
install and test all piles as indicated in Book II, “Summary of Work”, and as
specified herein and as shown on the bid drawings.
CODES AND STANDARDS
Contractor shall comply with the requirements
of Book II, “Codes and Standards”.
Conform especially to the applicable provisions
of the following codes and standards.
ASTM .......... American Society for Testing and
Material
ACI .......... American
Concrete Institute
JIS .......... Japan
Industrial standard
SOIL DATA
The Contractor shall carry out soil
investigation and shall state it in his bid proposal. The investigation program
shall be subject to the Owner’s approval.
BORED PILES
MATERIAL
The bored piles shall
conform to the requirements of ASTN
BS8004-1986.
The concrete for piles
shall use the cement Portland type II.
DESIGN CRITERIA
Bored piles with a
capacity of the single pile of 71 ton shall be used. The safety factor F
against pile failure shall be F = Pfailure / Peffective = 2.0. The allowable
concrete stress shall be limited to 60 kg/cm².
All details with respect
to the pile dimensions, length, reinforcement, cover plates etc. shall be show
on the Bidder’s shop drawings, and shall be subject to approval by the
Employer.
All reinforcing shall be deformed steel bars
conforming to Grade 400 ASTM A615M.
PILING EQUIPMENT,
INSTALLATION AND WORKMAN SHIP
BORING EQUIPMENT
The Bidder shall submit
with the Bid Proposal full details of the proposed pile boring equipment and
the method of carrying out the work, such information shall include, a full
description of the frames lifting devices and other equipment needed for the
installation.
The equipment shall be
capable of boring through bearing strata, boulders, shales, staff clays,
gravels, sand and limestone, and shall be capable of shunking bore holes in
diameters within the range of 600 mm 1500 mm and down to depths of 40 meters.
The diameters of both
augers and clearing bucket shall be least equal to the diameters of pile to be
installed. Where inclined rock surfaces are encountered, a coring bucket shall
be used to level the rock surface before commencing with chilselling or coring.
The Bidder shall allow in the unit rate of the pile all costs for consequent
enlargement of the pile arising from overboring, including additional concrete
resulting from such enlargement.
LENGTH OF PILES
The length of the piles
shall be as necessary to develop the required pile capacity. The Bidder shall
determine length of piles based on geotechnical data and shall be proven by
pile load tests.
SETTING OUT
The Bidder shall provide
all pegs, rods, survey instruments, concrete posts etc. needed for setting out
the works. The Bidder is to ensure that boundary marks defining the limits of
owners property are in their correct positions. The Bidder shall be responsible
for setting out the piles from the approved drawings and boundary marks, and
for date guarding the position and level of all reference pegs, boundary and
bench marks used for setting out the piles.
BORING ON PILES
All piles shall satisfy the tolerances for
position and inclinations as stated herein. The deviation in position of center
of pile or the projection of its center line from the pile center point as
shown on the setting out drawing shall not exceed 75 mm in any direction from
the true position of the same pile, provided also that the center of pile shall
not deviate laterally from the true center of the same pile by more than 40 mm.
If any pile has been installed out of plan or
line beyond allowable tolerance the Bidder shall be responsible to remedy as
noted above as no cost to the Employer.
Piles shall not bored so close to adjacent piles
which have been recently cast and containing workable, unset of fresh concrete
such that a flow of concrete may be induced from or otherwise causing damage to
these adjacent piles.
No pile shall be bored or pile casing be driven
nearer that five times its diameter (measured center to center) from an
unfilled pile borehole or from uncased concrete pile where the concrete had
been placed less than 24 hours previously.
On completion of boring and immediately prior to
casting, all loose, disturbed or remolded soil or rock shall be removed from
the base of the pile. Unless otherwise agreed, cleaning of the pile base shall
be carried out by means of a flat bottom cleaning bucket. In case of deep piles
with lengths in excess of 50 meters or where debris at the bottom of the bore
cannot be broken down sufficiently to facilitate extraction by cleaning bucket
method, the air lift (grab bucket) method may be employed in combination with
the flat bottom cleaning bucket to clean the base of pile. In such cases, a
final round of cleaning by the flat bottom bucket should always be carried out
before casting can proceed.
In the event of rapid loss of drilling fluid
from the pile excavation, the excavation shall be backfilled without delay with
available material up to a level where no further loss of drilling fluid is
observed. The Bidder shall investigate and determine the cause of fluid loss
while the pile excavation is left to stabilize under the action of the drilling
fluid. Based on the outcome of his investigation, the Bidder shall submit for
agreement his proposed method of construction before resuming pile.
All reasonable steps shall be taken to prevent
the spills of drilling fluid at site in the areas outside the immediate
vicinity of the bore. In particular, discarded bentonite shall be removed from
the site without delay. Any disposal of bentonite shall comply with the
regulation of the local controlling authority.
Any damage pile shall be abandoned, replaced or repaired
as approved of the Owner at the Bidder’s expense. Abandoned piles shall be
filled with soil and no cost to the Employer. Additional piles shall be
installed as requested, to provide for load conditions and to avoid
overstressing of piles. The Bidder shall be responsible to install additional
piles at no cost to the Owner.
CONCRETING
The requirements of the Concrete Specification
shall apply to the construction of bored piles.
The concrete for each
pile shall be from the same source. The bidder is to ensure that the supply
from whatever source (whether site-mixed or ready-mixed) is of sufficient
quantity so that concrete for each pile shall be placed without such
interruption as would allow the workability of the previously placed batch to
have deteriorated significantly.
All holes bored shall be concreted within the
same day. In the event of rain, the Bidder is to provide adequate shelter to
keep the hole dry and to concrete under cover.
The method of placing and the workability of
concrete shall be such that a continuous monolithic concrete shaft of the full
cross-section is formed. The method of placing shall be approved by the Owner.
The Bidder shall take all precautions in the design of the mix and the
placement of concrete to avoid arching of the concrete in the pile shaft. No
spoil, liquid or other deleterious matter shall be allowed to contaminate the
concrete.
PILE CUT-OFF
Concrete shall be
finished not less than 500 mm above the cut-off level (“overcast”) to ensure
that all concrete at and below cut-off level is homogeneous and free of
laitance and deleterious matter. A thicker overcast may be required by the
Employer depending on site conditions, and this shall be carried out without
extra cost. The overcast shall be chipped off level later by the Bidder.
CONNECTION BETWEEN PILES AND PILE CAPS
Adequate structural
connection between the piles and the caps shall be provided to suit design
taking into account the seismic requirements.
RECORDS OF PILE CONSTRUCTION
During the course of the
work, the Bidder shall maintain a complete record of pile construction and the
Bidder shall submit to the Owner, in an approved format, a record to reach
pile. Each pile record shall be submitted immediately after completion of each
pile and shall include:
§
Type,
location and site of pile.
§
Pile
number and all principle characteristics of pile including dimensions.
§
Details
of boring and concreting sequence progress, including dates, times, equipment
used and personnel (operator, Employer, etc).
§
Actual
location of piles, with variation from plan locations and inclination as
indicated.
§
Date
and Time of Boring
§
Weather
Condition.
§
Ground
level before commencement of pile installations
§
Pile
cut-off level.
§
Length
Temporary casting.
§
Any
unusual phenomena encountered.
§
Depth
and type of soil strata
§
Observation
of ground water level and ground water in flow.
§
Name
of inspector for each pile.
PILE LOAD TESTING
SCOPE OF WORK
Work specified under
this section includes furnishing all labor, materials and equipment for
compression, tension and lateral load testing of the piles and the preparation
in submission of the pile test reports.
The test piles shall be
constructed to the depths approved by the Employer.
Keep a record of the
test piles in accordance with the requirements set forth in Clause mentioned above.
The pile load testing
shall be carried out to the satisfaction of the Employer.
Upon completion of the
preliminary pile load testing, Bidder shall cut off the preliminary test piles,
as directed by the Employer and dispose of the cut off position.
METHOD OF TESTS
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 shall be capable of applying a
test 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 co-axial with the pile.
Man 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 measuring and testing equipment or for other
mechanical reasons or for reasons which the Bidder is responsible, the Owner
shall order the test abandoned and replaced by a new test on another pile at
and adjacent location at no additional cost.
Prior to driving each preliminary test pile, the
Bidder shall drill a bore hole 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 1.5 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 Bidder 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 firm and
independent support driven not less than 2.5 m from the nearest point of the
test pile of anchor piles.
The calibrated load cell shall be used for the
load measurement.
COMPRESSIVE LOAD TESTS
Perform compressive load tests on individual
piles in 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 piles 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 employer. 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 access of standard load
test, as specified in ASTM D1143. Test loads 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
tests 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.
TENSILE LOAD TESTS
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. The test shall include the cyclical load test of ASTM
D3689.
Loading shall be increased until failure occurs.
Tension tests 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 radial 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 in cast in place top
piles until installation of reinforcement, tell tales and tension connection is
complete. Design of tension connection shall be Bidder’s responsibility.
LATERAL LOAD TESTS
Perform lateral load tests on single piles in
accordance with the applicable requirements of ASTM D3966. Tests 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 standard load test load, with cyclic
loading, as specified in ASTM D3966.
Loading shall be increased until failure occurs.
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 but movement and rotation of the
head of the test piles.
Failure shall be defined as the load at which
horizontal deflection continues to increase without any further increase in
load.
TEST EQUIPMENT AND MATERIALS
Provide all equipment and materials required for
the tests and remove all such equipment and materials at conclusion of tests.
Submit drawings of test arrangement, including
full data for equipment and materials, for review and Employer approval, in
accordance with the requirements set forth in Book II.
Test Results: Submit test results complete with
tabulation of all test data to the Employer 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.
The Employer 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 will be tested.
The preliminary load tests shall be carried out
on 3 piles diameter 60 cm and 3 piles diameter 90 cm. The location of the piles
will be designated by the owner.
CONCRETE PILE
PILE TYPE
Proposal
A proposal shall be
submitted for the Circular Hollow Prestressed
Concrete Piles. The Contractor shall submit with the bid proposal
details of the proposed pile indicating the outside diameter and length.
Contractor
shall be fully responsible for furnishing the diameter required for driving
sound piles. Head of piles shall have sufficient strength to with stand
hammering, and concrete pile strength shall also be sufficient to withstand
ground pressure from driving adjacent piles.
MATERIALS
(CIRCULAR HOLLOW
PRESTRESSED CONCRETE PILES)
Circular Hollow
Prestressed Concrete Piles shall have minimum outside diameter of 300 mm and
shall conform to the requirements of ACI 313 – 1983 and ACI 543 - 1974 or JIS
G-5335/1997 and JIS G-3536/1983 (or latest). All piles shall be new and shall
be made locally.
Piles shall be supplied
free from harmful defects and of good commercial finish with regard to
smoothness and freedom from loose scale and rust.
The certificate of test
performed on material to be used for plies shall be submitted to the Owner
prior to pile acceptance and manufacturing.
When requested by the
Owner, the Contractor shall accompany the Owner to the place of manufacture to
witness tests and inspections carried out on the piles.
For each consignment of
piles delivered to the site, the Contractor shall submit to the Owner copies of
the manufacturer’s certificate.
CIRCULAR HOLLOW
PRESTRESSED CONCRETE PILES DESIGN
Design
of hollow prestressed concrete piling with concrete cover of minimum 50 mm and
with minimum diameter of 600 mm for the major structures and 350 or 400 mm for
others will be considered for acceptance by the Owner.
The
Contractor shall submit calculations indicating that the pile design is based
on the allowable loads, including safety factors, considering the soil data and
structural loading carried by the pile.
Concrete
compressive strength shall be minimum 500 kg/cm2, by using cement
type II.
The
total number of prestressed strands may be varied by increasing the number or
size of the prestressing strands.
Prestressing
reinforcement shall be stress relieved steel wire conforming to JIS G-3536 and
the prestress steel breaking strength shall be minimum 155 kg/mm2.
All
other non prestressing reinforcing shall be deformed steel bars conforming to
JIS-G-3112 grade 40, ASTM-A615.
Spiral
reinforcing shall confirm to the requirement of ASTM-A82.
JOINING
Splicing of piles shall
be performed by “Pile Manufacturer’s Procedure”. Pile splices shall be located
at a minimum of 3 m below the cutoff elevation. Splice strength shall not be
less than pile bending and tensile capacity.
CONCRETE
PILE HANDLING AND TRANSPORT
Length
of concrete piles shall be determined as to allow proper handling and
transportation of concrete piles, and shall be subject to Owner’s approval.
Complete
piles shall be transported and delivered to the site free of any damage.
LINES AND GRADES
Contractor
shall lay out lines and grades and be fully responsible for correctness of such
lines and grades and for proper execution of the Work to such lines and grades.
All
surveying shall be in accordance with Specification refers to “Surveying and
Setting Out” and “Erection and Commissioning”.