5. VERIFICATION AND SUBMISSIONS
5.1 Submissions
5.1.1 Submission at Tender
Submit the following details with the tender:
a. Proposals to deal with noise and vibration, and an assessment of vibration
characteristics
for
the different piling operations and how they will attenuate with
distance.
b. Details of method of achieving penetration of the piles, as well as through
obstructions.
c. Details of method of avoidance of critical services.
d. Work programme indicating the anticipated time required for installation of the
piles from
(commencement of site works/start of
excavation) to completion.
e. Track records showing evidence of experience of
this type of work. f. General methods for control of the piling works.
g. Confirm that the ground investigation information provided is adequate for the
piling works and design verification.
List any concerns in the tender.
h. Details of the action that would be taken to stabilise an excavation if for any
reason the completion to
the
excavation
of
the concreting
is delayed or prevented.
5.1.2 Method Statement
Prior to commencement of piling works, submit a method statement for the proposed method of installation to achieve the required performance including:
a. All relevant details of the method proposed during
tender, including details of the method of transporting and placing concrete /
grout in piles and how the specified
casting level tolerance will be achieved.
b. Method of overcoming any
obstructions encountered and drilling through hard rock
and ensuring no soil collapse within the borehole. Include details of the
reversed circulation drilling,
chiseling or other
method as proposed.
c. Methods to achieve the specified maximum permitted verticality of pile. Method of checking the
verticality and corrective actions
to be taken
if
the deviation exceeds the maximum permitted limits
d. Methods for installing piles in ground which exhibits Artesian conditions at depth e.
Details of proposed
plant and boring equipment
f. Details of proposed monitoring equipment g.
Details of specialists used for grouting
h. Details of concrete and grout
mixes i. Methods of concreting and grouting
j. Methods of handling reinforcement
k. Details of spacers to be used on reinforcement
cage
l. Details of permanent casing and the method of installation
m.
Details and properties of
support fluid.
Do not commence work for working piles before proposed methods are accepted.
NPQS
C4-10 Bored Piling Piles
5.1.3 Piling Programme
Submit to SO’s
acceptance the sequence and programme of working pile
installation. Inform
the
SO of
the
piling programme
scheduled for the following
day and give adequate notice of any intention to work outside normal hours and at weekends.
5.1.4 Monitoring of Adjacent Structures
Provide proposals for surveys and monitoring of movement and vibration in adjacent
structures and services (e.g.
VLCC) before work commences.
5.1.5 As-Built Details
Submit as-built details of the piling works on A1 size drawings including at least the
following details:
a. Final setting out plan, pile depths, pile sizes, pile capacities, pile eccentricities, pile lengths and cut-off levels.
b. Location of piles which have been discarded and not in use, e.g. abandoned piles, unused existing foundation, rejected piles and preliminary test
piles.
c. Location and type of pile load tests.
Submit these drawings to the SO endorsed by a PE within 2 weeks upon completing the works.
5.1.6 Quality Control Plan
Prepare and submit the quality control plan for SO’s acceptance prior
to
starting work.
5.2 Inspection and Test Certificates
5.2.1 General
Provide the SO with test certificates, analyses and mill sheets. Ensure that adequate
notice is
given to the SO
when
the processes
can be inspected or tests can
be witnessed.
Inspect each pile bore prior to the placing of concrete in it. Provide suitable equipment to
the
SO’s acceptance for
carrying out the inspection.
5.2.2 Inspection of Bores
Inspect each pile bore prior to the placing of concrete in it. Provide suitable equipment to
the
SO’s acceptance for
carrying out the inspection.
Where the borehole is dry inspect
from
ground level to ensure that:
a. The base is adequately clean
b. The shaft is stable
c. The bore has been constructed within specified tolerances
Provide adequate lighting, measuring tapes and the means of measuring verticality.
Keep record of the inspection of bores.
NPQS
C4-10 Bored Piling Piles
5.3 Tests
5.3.1 Compliance Testing of Concrete and Reinforcement
Refer to requirements as set out in sections C3-10, clause 5.1 and section C3-20,clause
5.0.
5.3.2 Grout
Testing
Carry out cube testing in accordance with SS 78:
Part A16.
Each sample is to
comprise
six
cubes, three for testing at seven
days and three fortesting at 28 days after casting.
5.4 Compliance Testing of Drilling Fluid
5.4.1 Verification of Drilling Fluid Material
Provide a certificate
from
the manufacturer of the drilling powder, showing the properties
of each consignment
delivered
to the
site.
The properties
to be given by the
manufacturer are the apparent viscosity range (in centipoises) and the gel strength range (in Newton’s per square metre) for solids in water.
5.4.2 Frequency of Testing
Propose the frequency
of testing drilling fluid and the method and procedure of sampling prior to the commencement of the work. The
frequency may
subsequently be varied as required,
depending on the consistency of the results obtained.
Measure the density
of freshly mixed drilling fluid suspension daily as a check on the quality
of
the suspension being formed. The
measuring device is to be calibrated to read
to
within 0.005 g/ml.
5.4.3 Testing Laboratory
Establish a suitably equipped and maintained site laboratory
for testing the support fluid. Provide skilled staff
and all necessary apparatus to carry out
the
sampling and testing.
5.4.4 Testing
5.4.4.1 Batch Testing
Tests to determine density, viscosity, shear strength and pH value is to be applied to
each batch of freshly
mixed or reconditioned drilling fluid supplied to the pile boring and
the results
submitted before
the batch is
used in
excavations.
For
average soil
conditions, the results are to generally be within the ranges stated in Table 5.4.4.2below.
Carry out the tests until a consistent working pattern has been established, take account of the mixing process, any blending of freshly mixed drilling fluid suspension and previously used drilling fluid suspension and any process which may be used to remove impurities from previously used drilling fluid suspension.
When the results show consistent behaviour, the tests for shear strength and pH value
may be discontinued, and tests to determine density
and viscosity is to be carried out as
agreed. In the event of a change in the established working pattern, tests for shear strength and pH value is to be re-introduced for
a period, if required.
5.4.4.2 Testing from Bore
At least one sample of fluid is to be taken
from
the base of the excavation and one from
the
top immediately
prior to placing reinforcement and concrete. Compliance values are as stipulated below.
NPQS
C4-10 Bored Piling Piles
Table 5.4.4.2 Drilling Fluid Properties
Property
to be measured
|
Range of results –
Freshly mixed fluid
|
Range of results – sample from bore prior to placing steel
and concrete
|
Test Method
|
Density
|
Less than 1.10 g/ml
|
Less than 1.10 g/ml
|
Mud density balance
|
Viscosity
|
30-90s or less than
20 cP
|
33-42 s
|
Marsh cone or
Fann viscometer
|
Shear strength (10
minute gel strength)
|
1.4 – 10.0 N/m2 or
4.0 – 40.0 N/m2
|
1.4 - 10.0 N/m2 or
4.0 - 40.0 N/m2
|
Shearometer or
Fann Viscometer
|
PH
|
9.5 – 12.0
|
9.5-12.0
|
pH indicator
paper
strips or electrical pH
meter
|
Sand content
|
Less than 4%
|
Less than 2%
|
Wet sieving
through
210 BS Mesh
|
5.5 Pile Testing
For general requirement and procedures of the pile load tests refer to Section C4-30
“Pile Testing”, clause 4.0.
5.5.1 Preliminary Piles
Refer to section C4-30, clause 4.1 for requirements of the preliminary pile(s). Agree locations with the SO.
5.5.2 Working Pile Testing
Refer to section C4-30,
clause 4.1 for the requirement
of
working pile tests.
5.5.3 Remedial
measures
5.5.3.1 Piles Carrying Gravity Loads
For each pile test that has
failed, propose and provide one or more substitute compensating piles for acceptance by the SO. If, in the opinion of the SO,
it
is impractical or inadvisable to install substitute piles in place of a failed pile, submit proposals to rectify the defect.
The
proposal is subject
to
the acceptance of the SO.
5.5.3.2 Piles Carrying Lateral Loads
In the event that a pile fails a lateral working load test, carry out remedial measures as follows:
a. Carry out a structural assessment to ensure the pile is structurally sound.
b. Excavation of all materials for a distance of not less than 5m from pile face around the entire pile to minimum 1m below the level of the pile cap soffit. The
width of excavation is to be the same on all sides of the pile.
c. Backfilling and compaction of the excavation hard against the pile and testing and
re-testing as appropriate. Finally, completion of backfilling and compaction to the
level of the top of the pilecap.
d. Alternative remedial measures such as compensating piles may be proposed subject to the acceptance of the SO. Carry out additional load tests as directed by the SO.
5.6 Records
NPQS
C4-10 Bored Piling Piles
Keep records of the
installation
of each pile with information
as below. Submit two
copies of these records to the SO the next working day after the pile was installed or as
directed. Note any unexpected boring conditions in the record.
a. Contract
b. Pile reference number
(location)
c. Pile type
d. Nominal cross-sectional dimensions or diameter e.
Nominal diameter of under ream
f. Length of preformed pile
g. Standing groundwater
level
h. Date and time of boring
i. Date of concreting / grouting
j. Ground
level at commencement
of
installation of
pile k. Working level
l. Depth from working level to pile toe
m. Toe level
n. Depth from working level to pile head level o.
Length of
temporary casing
p. Length of permanent casing
q. A log of soil type encountered from start to finish of excavation and observed water levels.
r. Length and details of reinforcement
s. Concrete /
Grout mix
t. Volume of
concrete / grout supplied to pile where this can
be measured in
practice
u. A graph of
theoretical and placed concrete / grout
volumes with depth.
v. All information regarding obstructions/delays
and
other Interruptions
to the
sequence of work
5.6.1 Grouting Records
Provide duplicate records within 24 hours of completion of grouting, showing:
a. Pile identification b. Date
c. Leakage test
d. Records of pressure and uplift e.
Total uplift
f. Grout test
results
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