bored piling - 20678695.s21i.faiusr.com

PROPOSED BRIDGE CROSSING SUNGAI PULAI AND LINK ROAD FROM PELABUHAN

TANJUNG PELEPAS TO TANJUNG BIN,

MUKIM AIR MASIN AND SUNGAI KARANG DAERAH PONTIAN AND MUKIM PULAI,

DAERAH JOHOR BAHRU, JOHOR DARUL TAKZIM.

METHOD STATEMENT

BORED PILING

MARCH 2018

Qiwei Wu

SINOHYDRO FOUNDATION ENGINEERING COMPANY LINITED

TIAN JIN 301700

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Table of Contents

1.0 SCOPE OF WORK..................................................................................................... 3

1.1 General Description .............................................................................................. 3

1.2 Reference .............................................................................................................. 3

1.3 Materials ................................................................................................................ 3

1.4 Plant and Equipment ............................................................................................ 3

1.5 Manpower .............................................................................................................. 4

1.6 Construction Procedures ..................................................................................... 5

2.0 SAFETY AND HEALTH ........................................................................................... 18

2.1 Job Safety & Health Analysis ............................................................................. 18

2.2 Information to Personnel .................................................................................... 18

2.3 Emergency Arrangements ................................................................................. 18

2.4 Permit Requirements .......................................................................................... 19

3.0 ENVIRONMENTAL ISSUES .................................................................................... 19

3.1 Environmental Aspects, Impacts & Control Measures ..................................... 19

4.0 QUALITY ASSURANCE & QUALITY CONTROL .................................................... 19

4.1 Contractual Requirements ................................................................................. 19

4.2 Inspection & Testing ........................................................................................... 20

4.3 Follow up & Evaluation ....................................................................................... 20

5.0 APPENDICES .......................................................................................................... 20

5.1 Construction Sequence Flow ............................................................................. 20

5.2 Job Safety & Health Analysis (JSA)................................................................... 21

5.3 Environmental Aspect Impact Register (EAIR) ................................................. 21

5.4 Inspection Test Plan (ITP) .................................................................................. 21

5.5 Quality Control Site Inspection Checklist ......................................................... 29

5.6 Recycle System for Drilling Fluid ...................................................................... 30

5.7 Proposed Location of Bore Pile ......................................................................... 31

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1.0 SCOPE OF WORK

1.1 General Description

This method statement is to describe the methodology of bored piling construction

serves as the foundation of the project.

No bored pile excavation shall be carried out within a distance of 5 pile diameter

center to center from an open pile under excavation or a pile which has been

concreted less than 24 hours.

1.2 Reference

No Description Document or Ref. No.

1 Technical Specification

Section – Piling Works JKR STANDARD SPECS

2 Drawings – Piling Works Tender Drawings

1.3 Materials

No Description Purpose

1 Concrete For concreting works

2 High Tensile Steel

Reinforcement Bars

For fabricating rebar cage

3 Drilling Fluid (Bentonite) To support bore hole from collapse

4 Sonic Logging Tube To install/ fix to rebar cage for sonic logging

test

5 Concrete Spacer Block For concrete cover

6 Tie Wire For tying rebar and spacer block

7 Joint Coupler For jointing main reinforcement of rebar cage

1.4 Plant and Equipment

No Plant and

Machinery Purpose

1

Hydraulic Drilling Rig

Attached with

Telescopic Kelly Bar

For bored pile drilling works

2 Mobile Crane For hoisting of equipment / materials

(reinforcement cage, boring tools, vibro

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No Plant and

Machinery Purpose

hammer etc.

3

Drilling Tools (Auger,

boring bucket, core

barrel, cleaning

bucket)

To be attached to drilling rig for boring of

soil/rock

4 Excavator To prepare site platform for drilling rig/removal

of excavated material

5 Fluid Plant (when

required)

For bentonite suspension to be used to

stabilize bored hole

6 Tremie set For concreting bored pile in wet condition

7 Water Pump For pumping water

8 U-bolt and Welding

Set and Coupler

To carry out works for reinforcement cage,

testing instrument, etc.

9 Generator Set To supply electricity for equipment

10 Vibrating Hammer To install / removal of temporary casing

11 Steel Plate Machine platform on soft ground

12 Tower Light / Lighting To illuminate work area when dark

1.5 Manpower

No. Description No. of

person Brief Roles and Responsibilities

1 Project Manager 1

Overall authority and responsible for the

execution of the work including anticipated job

quality, effective cost control and schedule

control

2 QAQC Manager 1 To ensure works on site comply to QAQC

standard and control

3 Site Engineer 1 Planning & monitoring site construction

activities

4 Site Supervisor 3 Supervising site construction activities

6 Rigger 3 To ensure all rigging and slinging activity follow

the safe technique and follow SOP

7 Rebar Worker 6

Cut and fit wire mesh or fabric, using hooked

rods, and position fabric or mesh in concrete to

reinforce concrete.

8 SHE Supervisor 1 Conduct site toolbox meeting and make sure

all site activities follow safety and health

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*

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unt of manpower to be deployed is tentative, the actual manpower will be

changed whenever necessary according to actual site condition.

1.6 Construction Procedures

1.6.1 Preparation of platform work area

Storage of Reinforcement at Site: Reinforcement shall be stored on

timber sleeper on firm ground and under shade to avoid bending due

to unequal settlement under self-weight of itself. They shall be stacked

in manner as to allow easy identification and lifting. Reinforcement

shall be protected from rain by plastic sheet covering to avoid

excessive corrosion or rusting.

Platform Preparation and Setting Out: The bored pile position must be

free from underground services and utilities. The firm, solid platform is

mandatory and equipment must be seated on firm platform which shall

be flat and compacted to receive the boring rig and crawler crane.

Steel plate may be needed on top of prepared platform for boring rig to

be seated so as to evenly distributed load over ground.

1.6.2 Setting Out and Positioning

Surveyor will first set out the position of bored pile as per the approved

construction drawing. The pile position will be marked with peg

indicating of bored pile identification, its depth and size. Existing

ground level at the pile position will also be recorded prior to drilling.

Figure 1: Setting Out Bored Pile Location

regulation

9 General Worker 8 Conduct general works at site

10 Machine Operator 3 Operating the plant and machinery during the

works

11 QC Engineer 2 Quality inspection / checking for the piling work

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Boring plant will then mobilize to the intended bored pile position and

position the centre of auger exactly above the pile point.

Figure 2: Positioning of boring plant over bored pile position

Verticality of the Kelly bar shall be checked before boring commences.

The verticality of the Kelly bar will be controlled by means of a plumb

line. Adjustment should be made so as to enable the Kelly bar to be as

vertical as possible and subsequently the position of the auger is

checked against the pile point. Adjustments should be made so that

the centre of the auger is nearest to the pile point to ensure that the

tolerances of 75mm deviation can be maintained. The auger is then

lowered and boring operation commenced. Surveyor will also cross

check the final coordinate position prior to the casing installation during

pre-bore to give approval of the deviation.

Reasonable care should be taken so that the pile position and

verticality are constructed within the specified tolerance i.e. 75mm and

1 in 75 respectively.

Two reference points with distance of 1.5m from pile centre

perpendicular to each other from the pile position will be offset and set

on site.

Working platform for the bored piling area shall be ensured firm and

stable prior to the boring operation. Steel plate shall be used for the

boring plant to sit on to strengthen the platform whenever necessary.

1.6.3 Boring Operation

When all the associated technical information is confirmed and

clarified (i.e. presence of services, pile coordinate, platform, cut off

level, pile length, validity of drawing, etc.), boring shall commenced to

the required size and depth. The boring work permit to be obtained

before boring work starts.

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Figure 3: Commencement of boring operation

Stability of the borehole will be observed during boring works. If the

borehole is unstable and collapsible, temporary casing will be inserted

into the borehole. Verticality of the temporary casing will be checked

during installation using the plumbs positioned in perpendicular

direction to each other and spirit level. The casing shall be positioned

within the tolerance and permitted deviation of 1H:75V after driving.

Usually temporary casing shall be advanced until hard strata to cover

all the loose, unstable granular material or water bearing strata at all

times.

The length of the casing will be determined from actual conditions

encountered on site. Single walled temporary casing will be installed

using double jaws vibro hammer attached to the crawler crane.

All temporary casings shall be free from significant distortion. They

shall be of uniform cross section throughout each continuous length.

Temporary casing shall be exposed 1m above existing ground level. If

the casing unable to be protrude less than 1m, a rigid barrier will be

provided around the casing and tout wire mesh stretch over at the top

of casing.

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Figure 4: Insertion of temporary casing

To have better control on the deviation of pile position, prior to the

commencement of boring, the casing will be again checked for

positional tolerance according to Figure 5. The verticality of casing

shall be checked by using spirit level and plumb and recorded on As-

Built field sheet. Casing shall be re-driven if casing deviates more than

75mm.

Figure 5 : Cross section of top of casing

Excavation of bored pile shall be using rotary kelly and auger/ bucket

method, depending on the soil condition and strata. In soil condition,

boring is using auger or boring bucket (Figure 6a & 6b) while for hard

material or rock encountered during boring is using core barrel (round

shank, stolen, roller bit), boring operation shall be carried out until the

bored pile designed depth is achieved.

Survey point

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When encounter rock head layer, SC representatives will be informed

and witness to verify the depth of rock head. Exact time of changing of

boring bucket to rock coring tool shall be recorded.

Figure 6: Method of boring

A detailed record of all encountered ground conditions together with

associated times, types of equipment and materials used and any

occurrences on site will be recorded on the Pile Bore Log and Field

Sheet.

SC will be informed immediately if the rock level encountered during

construction varies more than 1m from that shown in the approved

construction drawings. Same notification will be given when cavity is

encountered. The actual rock coring duration to reach the design toe

level must be accurately recorded.

Rock excavation length shall be measured from the lowest level of the

flattened horizontal bedrock surface. Collected rock samples to be

inspected at site. The result of sample shall be sent to SC as soon as

possible to confirm the final toe level.

Whenever required, drilling fluid bentonite or approved drilling fluid

(water) shall be filled before advancing the drilling process below the

bottom of the casing. The testing of bentonite i.e. viscosity, density and

sand content shall be conducted on site as necessary. Drilling fluid will

always be directed to the nearest tank/container/pond with earth bank

to prevent spill over of slurry and messed up the working area. The

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dimension for the recycling tanks are 6100(Length) X 2400(Width) X

2500(Height)

Illustration of bored piling work area set up is further illustrate in Figure

A, B, C below.

Figure A: Bore Piling Set Up Illustration within Green Area (For 2 piers)

Figure B: Bore Piling Set Up Illustration within Green Area

(For 1 Pier/ Test Pile)

Approx. 100m (max) – 2 pier location

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Figure C: Bore Piling Set Up Illustration within Traffic Island Area

The head of the drilling fluid will be kept at a level high enough to

ensure sufficient stabilizing capacity in the uncased shaft area. The

fluid used for drilling purposes will be supplied to the pile from the fluid

plant storage area via a supply line.

The level of the drilling fluid will be kept constant above ground water

level and will be monitored during the whole drilling process. If

extensive fluid loss occurs during drilling, the drilling will be stopped

immediately. The borehole will be backfilled with lean concrete or

mortar in order to create a plug surrounding the pile shaft. Re-drilling

will then take place within 2 hours. If further fluid loss or shaft collapse

occurs, the bore will be immediately backfilled with low strength, lean

mix concrete prior to any further excavation taking place. There will

have a sedimentation plant that will be maintain everyday by excavator

and will sent out from site.

Reasonable steps will be taken to prevent the spillage of drilling fluid

suspension on the site (i.e. circulation pumping system set up on site

for green area, direct pumping system/earth bank/ sump pit for

near/adjacent road/public access), depending on the working area.

Upon completion of a bored pile hole, the contractor shall immediately

submit a log of the bore to the SC. A joint inspection with SC will be

conducted to verify the depth and checking the cleanliness. After

assessing the results, the SC may instruct the contractor to proceed

with the installation of the bored pile or may instruct the contractor to

further advance the depth of the boring until further drilling confirms

that a sound founding level has been reached.

1.6.4 Cleaning of Pile Base and Verification of Pile Length

Note: Actual set up shall be modified for any unforeseen obstruction

found on site from time to time

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The boring process will be continued to the final depth length for each

designated bored pile length specified in the approved construction

drawing.

After reaching the depth of bored pile, the base of the borehole will be

cleaned until the final required depth. Loose and reshaped material

shall be removed.

Figure 7: Cleaning of Pile Base

After complete pile base cleaning, Supervision Consultant (SC) will be

invited to verify and confirm the final toe level of the pile and

termination of soil/rock prior to placement of reinforcement cage by

using measuring tape. The bored pile length confirmed and agreed by

Consultant shall be recorded in the inspection request and pile bore

log. Pile length, rock head level, type of drilling tool and penetration

rate will all be recorded.

1.6.5 Spoil Removal

Spoil earth for the borehole will be cleared from the boring locations by

using excavator. The spoil earth will first be placed near to the

borehole location until dry enough for transportation out under sunlight

and wind factor.

1.6.6 Installation of Reinforcement Cage

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The reinforcement cage will be installed in prefabricated sections near

to the bore pile location. Reinforcement and dimension of the cage will

be erected according to the approved construction drawings and

specifications. A joint inspection with SC will be conducted for all rebar

cage to verify the size, type, length and related. Verification of the

correctness and cleanliness of the cages will be recorded in the Pile

Bore Log Sheet.

Steel cage will be fabricated at yard and will be transferred to site by

cargo trailer. Cage Fabrication Platform will be erected for fabrication

of more than 600mm diameter. Timber wedges will be provided to

prevent rolling of steel cages when fabricating horizontally.

The maximum length of rebar cage sent out to yard is 12m. The cages

will be provided with stiffening rings (for pile diameter 1200mm and

above) at every 3m interval and other accessories to enable handling,

lifting and installation without permanent deformations. The cages will

be securely fixed using manually tied galvanized wire to link and

subsequently tap weld at lapping.

Sonic logging tubes, telltale extensometer and strain gauge wire tube

(using A9 retrievable extensometer method – only for preliminary test

pile which is instrumented) shall be installed inside the bored pile

reinforcement cage to the required protrusion level, only on selected

working pile and all preliminary test pile indicated and agreed by

PDP/SC. The instrumentation and monitoring access tubes need to

get consent from tester if they are to be welded to the cage.

If the structural reinforcement cage extends to the base of the pile

bore, these instrumentation and monitoring access tubes will be fixed

to the main reinforcement by mean of clamping or welding. However, if

the base of the pile bore exceeds the structural cage requirement by

more than 2 meters, the subsequent section will be joined by means of

threaded couplers and installed through the suspended reinforcement

cage to the case of the pile bore.

Sonic logging tubes shall be 4 nos. for pile diameter less than 1350mm,

and 6 nos. for pile diameter greater than 1350mm whereas for telltale

tubes and strain gauges, it shall be installed parallel to the axis of the

pile and terminating at each level as indicated in the approved

construction drawing.

Telltale extensometer and strain gauge wire tubes (for A9 retrievable

extensometer) are installed next to main bars will provided added

protection for the strain gauges during concreting.

The rebar cage will be fabricated to designed length before installing

to the complete bored hole. The rebar cage, which are required to be

pre-fabricated in length exceeding 12 meters. Similarly, these cages

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may be placed onto a supporting timber plank, which will be used to

carry the cage during lifting to the vertical.

Concrete cover wired to the cage will provide lateral support and

ensure adequate concrete cover.

Cages will be hoisted into the borehole using a crawler crane with

safety ledges of the required capacity. In cases where the structural

requirement of the reinforcing cage is less than the depth of the pile

bore, cages will be suspended in the bore hole using the “double hook”

system. “Double hook” system is by using two chain slings (same

length) to lift the steel cage (Figure 9). Cage shall be ensured to

maintain at the intended cut off level. Lapping of steel reinforcement

cage shall be weld using spot weld method or thread coupler (refer

Material Submission Approval for Jointec Coupler from Halfen Moment;

KVLRT3-WCTB-GS03-MAT-MSA-000011).

Figure 8: Installation of reinforcement cage

Figure 9: Double hook System

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Figure 10: Rebar cage with sonic logging tube

1.6.7 Concreting of Bored Pile

Slump test and temperature checking shall be monitored and

conducted as per specification. Slump test to be conducted on site at

the initial first hour whenever the idling period of concrete truck

exceeding one hour. Subsequent slump test shall be taken at half an

hour interval.

Concreting shall commence when reinforcement cage is secured

properly inside the bore hole. Concrete shall be carried out

continuously using tremie method. After installing the rebar cage,

another net sounding is required.

Tremie pipe shall be lowered to the toe of borehole not higher than

1.0m from the base. Polystyrene shall be inserted to prevent direct

contact between concrete with drilling fluid. As concrete rises 9m

upwards, 1-2nos of tremie pipe (3m/nos.) will be withdraw upwards as

well and ensure the end of tremie pipe is embedded into the concrete

at all times during concreting works. The end of tremie pipe shall be

kept immersed in the concrete to a depth of 3m at all times. When

concrete has reached above the cut of level, tremie pipe will be

withdrawn completely.

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Figure 11: Bored pile concreting (Tremie method)

Bored pile shall be concreted to a height at least 1m above the cut off

level and at least 0.5m above existing ground level to ensure the

concrete quality and integrity of the bored pile. Excess concrete shall

be removed to the specified cut off level once the concrete has

hardened prior to construction of pile cap. SC/PDP will be informed for

joint measure using plumb to confirm the top of concrete level.

Temporary casing shall be withdrawn slowly using vibratory hammer/

turntable and assisted by crawler crane to ensure no necking of the

pile at any level. Surface level of the sound, good concrete shall be

maintained at least 1.0m above the cut off level and at least 0.5m

above existing ground level before tremie pipe withdrawn. Casing shall

be extracted within 1 hours after placing of last pouring.

Figure 12: Extraction of temporary casing

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Any empty bore length will be normally backfilled with proper

compaction using previous excavated material/ suitable backfill

material after initial set of concrete and before complete withdrawal of

the temporary casing in cases where the concrete level is not brought

to the top of existing ground level.

Hacking of pile head shall be trim to the require cut off level and joint

measured by SC/PDP using plumb to confirm the top of concrete level

and recorded under SIR. The As-Built SIR will be compiled to SC/PDP

within 3 days.

After installing the rebar cage,

Upon completion of all piling works, the pile eccentricity and pile head

level will be checked by surveyor and subsequently produce the As-

Built drawings endorsed by the licensed surveyor showing the position

of piles as installed prior to pile cap construction.

1.6.8 Keep Field Records

There is no disturbing of concrete until it is fully hardened. When the

bore piles installation has been completed, the piling records shall

consist of below: -

a. Quality control inspection checklist

b. Pile bore log

c. Rebar cage check record

d. Pile concreting record

e. Pile displacement record

Borelog record and field record will be provided to PDP representative

the next following day before afternoon prior to works drilling ongoing.

All joint survey will be carried out between PDP/ WPC.

1.6.9 Survey of As-Built Pile Position

Pile As-Built position will be jointly surveyed by competent surveyor

and PDP/SC representatives. The tolerances as specified in the

technical specification section 120 (KVLRT3-MRCBGK-GEN-PMGT-

SPC-000002): Section 210.1.13 are: -

a. Deviation from axis of pile on plane not more than 75mm

b. Deviation from vertical, maximum 1:75

The deviation will be at any direction and will be shown in the As- Built

Drawing. Pile position and its eccentricity shall be determined by

having joint verification with PDP/SC along with surveyor after

completion of pile head hacking to the required intercept level. A steel

circular ring template according to the actual pile diameter shall be

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prepared and inserted to the casted bored pile and adjust to the best

position having to balance eccentricity between the casted concrete,

rebar cage and concrete cover. Once the position is determined and

agreed by all who present for the inspection, surveyor will mark out the

location using spray paint and survey the coordinate of the pile

position and it will be the As-Built for the actual pile position.

Figure 13: Illustration of determine pile position and its eccentricity

The record must be forwarded to PDP/SC before proceed with pile

head preparation. Submitted As-Built drawing shall be endorsed by

license surveyor.

2.0 SAFETY AND HEALTH

2.1 Job Safety & Health Analysis

Refer Appendix 5.2 for Job Safety & Health Analysis (JSA)

2.2 Information to Personnel

A briefing of the JSA of this method statement will be given to staff/

subcontractor involved in this works. The attendance record will be keep with

the JSA.

2.3 Emergency Arrangements

ORGANIZATION CHART OF THE EMERGENCY RESPONCE TEAM (ERT)

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2.4 Permit Requirements

No Description Authority Responsible

Personnel

1. Permit to Work WCT Safety & Health

personnel

3.0 ENVIRONMENTAL ISSUES

3.1 Environmental Aspects, Impacts & Control Measures

All activities at work site shall comply with requirements for Construction and

Completion of Light Rail Transit Line3 (LRT3) from Bandar Utama to Johan

Setia – GS03. Guidelines of this mitigation are tabulated in Environmental

Aspect & Impact Register as per Appendix 5.3.

4.0 QUALITY ASSURANCE & QUALITY CONTROL

4.1 Contractual Requirements

ERT CONTROLLER

Project Manager

Ta Kok Chang

019-2653837

DEPUTY ERT

CONTROLLER

Safety & Health Manager

Norazmi Mohamed Tahir

012-2327338

COMMUNICATION

COORDINATOR

Salmi Azuriza Bt

Che Ali

012-6546905

FIRE FIGHTING

/DAMAGE

CONTROL

COORDINATOR

Shahrolamri B.

Mohd Suhaimi

010-4335359

TRAFFIC

COORDINATOR

Rofie Mohamad

012-5058540

SEARCH &

RESCUE

COORDINATOR

Mohd Fahmi Bin

Zulkifli

013-2225946

EVACUATION

COORDINATOR

Mohd Attef Bin

Elman

019-3124638

First Aid

Coordinator

Mohd

Zahiruddin Bin

Mohd Zahari

014-8061784

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It is the contractual obligation of WPC to meet all the requirement outlines in:

-

a) Project Quality Plan

b) WCT Project Procedures.

Inspection and Testing (WCT-P-4.10)

Inspection, Measuring and Test Equipment

(WCT-P-4.11)

Inspection and Test Status (WCT-P-4.12)

Control of Nonconforming Product and Work

(WCT-P-4.13)

Handling, Storage, Packaging, Preservation and

Delivery (WCT-P-4.15)

c) General Specification; Section 8 – Quality Assurance and

Quality Control (QAQC)

4.2 Inspection & Testing

All inspection and test activities shall be undertaken in accordance with: -

a) General Specification: Section 9 – Inspection, Testing and

Commissioning and Integrated Test

b) Inspection and Test Plan (ITP) for Bored Piling

(Appendix 5.4)

4.3 Follow up & Evaluation

a) All necessary supervision and stringent checks shall be made during work

progress and final work done to ensure conformance with the

specifications, drawings and procedures as provided. Inspection and

supervision shall use the approved checklists (Appendix 5.5).

b) All materials used as permanent works shall only use the approved

material.

c) The handling, packaging and storage the material shall according to the

manufacturer’s instruction and all relevant government authorities.

d) Consultants shall issue the non-conformance report when the work or

material is not conforming or fail to meet the requirements outlined in the

Inspection and test plan.

e) The RFIs, checklists, records forms shall be ensured verified, completed

and comments (if any) and shall be closed and resolved to finalize all the

records.

f) The defects shall be identified, investigate and set approval/ agreement

from PDP/ SC before start any rectification work.

5.0 APPENDICES

5.1 Construction Sequence Flow

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5.2 Job Safety & Health Analysis (JSA)

5.3 Environmental Aspect Impact Register (EAIR)

5.4 Inspection Test Plan (ITP)

5.5 Quality Control Site Inspection Checklist

5.6 Recycle System for Drilling Fluid

5.7 Proposed Location of Bore Pile

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Appendix 5.1

Construction Sequence

FOR BORED PILING

Preparation of platform

work area

Setting out and

positioning bore pile

point

Boring Operation

Cleaning of pile base

and verification of pile

length

Spoil removal

Installation of

reinforcement cage

Concreting of Bored Pile

Keep field records

Survey as-built pile

position

Start

End

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Appendix 5.2

Job Safety & Health Analysis (JSA)

FOR BORED PILING

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Appendix 5.3

Environmental Aspect Impact

Register (EAIR)

FOR BORED PILING

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Appendix 5.4

Inspection & Test Plan (ITP)

FOR BORED PILING

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Appendix 5.5

Quality Control Site Inspection

Checklist

FOR BORED PILING

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Appendix 5.6

Recycle System for Drilling Fluid

FOR BORED PILING

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Appendix 5.7

Proposed Location of Bore Pile

FOR BORED PILING

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