TABLE OF CONTENTS Page
1.
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INTRODUCTION
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2
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2.
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SCOPE
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2
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3.
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OBJECTIVE
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2
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4.
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REFERENCE DOCUMENT
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2-3
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4.1 PROJECT DOCUMENTS AND SPECIFICATIONS
4.2 CONSTRUCTION DRAWINGS
5.
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DEFINITIONS
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3
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6.
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PERSONNEL
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3-7
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7.
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MACHINERY AND EQUIPMENT
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8
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8.
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MATERIALS
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8
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9. PROCEDURE
9 - 15
10. PROGRAMME
15
11. HEAL
TH, SAFETY AND ENVIRONMENT
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15-17
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12. RISK
ASSESSMENT
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18
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13. APPENDIX
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18
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1 INTRODUCTION
This method statement describes the procedure for construction of Reinforced Concrete Structural Works using conventional formwork at Sembcorp Energy-from-Waste Project, Sakra Road, Jurong Island.
2 SCOPE
This procedure applies to all the Reinforced Concrete Structural construction works which carried out at Sembcorp Energy-from-Waste Project including the construction ofpilecap, ground beam, base slab, top slab, columns, beams and walls.
3 OBJECTIVE
To ensure that Reinforced Concrete Structural Works carry out safely and complies
with safety requirement.
4 REFERENCE DOCUMENTS
Referencehas been made to the following related documents for these works:
4.1 Project Documents and Specifications
Ensure all of the works comply with Specifications from client
(a)
Doc No. SUTO-ALL-COS-4-006 entitled "SPECIFICATION AND STANDARD FOR CONCRETE"
Ensure all of the works comply
with Specifications from Supervising Structural Consultant
(a) Doc No. SLJT1-Z05-C01-4-001 entitled "CIVIL AND STRUCTURAL SPECIFICATIONS"
4.2 In-house Safety Rules and Regulation of Main Conractor
Ensure all of the works comply with the relevant requirements of Main Contractor.
3 Safe Work Procedure for Reinforced Concrete Structural Works
Ensure the Reinforced Concrete Structural Works carried out according to Safe Work
Procedure.
4.4 Construction Drawings from Main Contractor
Ensure all the works carry
out according to the latest approved Construction Drawings.
5 DEFINITIONS
6 PERSONNEL
The following personnel are engaged in Reinforced Concrete Structural work;
1. Site Supervisor
- 4
2. Formwork Safety Supervisor - I
3. Safety Coordinator - 1
4. Confined Space Safety Assessor - 1
5. Confined Space Supervisor - (All Site Supervisor attended Supervise work in CS)
6. Work at Height Supervisor (All Site Supervisor attended WAH Supervisor)
7. Lifting Supervisor - 2
8. Surveyor - 1
9. Crane Operator - 2
10. Rigger I
Signalman - 4
11. Surveyor's Chainman - 1
12. General Worker - 60
13. Pump Truck Operator - I
The number of supervision required depends on the size of working area and shall be adjusted accordingly.
All personnel shall be suitably qualified and experienced for tasks to be undertaken.
Additional task description for the key personnel is:
6.1 Safety Coordinator
• Support
and advise site management in their duty to
implement company and site - specific
HSE policies
and procedures
• Assure the adequacy of site and Client's HSE procedures
• Assess the work to determine compliance with HSE policies and procedures promptly, communicating concerns and recommendations to managers or supervisors for their action
• Take
immediate action on any imminent dangerous situation observed
• Advise and ensure the required personal protective equipment, safety equipment are provided and fit-for-use
• Ensure adequate investigation and analysis of accidents (non-injury and injury)
• Provide HSE information for the education of management, supervision and employees concerned
• Ensuring preparation, submission and maintenance of required HSE record keeping documentation such as inspection reports, training records, equipment log, toolbox meeting records, etc
6.2 Site Supervisor
• Ensure work is carried out complying with work method statement, permit to work and HSE
requirement
• Plan each task with
HSE as an integral part and conduct pre-job risk assessment of all work activities
• Assign employees only to task for which they are trained and qualified
• Monitor worker and work group performance for quality and safe work procedures
• Correct any deficiencies noted and educate the worker to improve work methods
• Report and investigate
all non-injury and incidents and secure incident scene
• Train the employees in safe work procedure
• Inform employees of potential health hazards
• Assure good housekeeping at all times
• Encourage crew members
to actively participate in the HSE program
• Enforce company and project HSE policies at all times
6.3 Formwork
Safety Supervisor
• Apply the WSH Act and its subsidiary legislations and relevant Codes of Practice
to the construction, erection, alteration or dismantling of any formwork structure in a worksite
• Assist in carrying out risk assessment for formwork activities
• Apply the fundamentals of formwork structure construction on site
• Ensure formwork structure construction is in accordance with approved design
• Identifyjob hazards and apply control measures
• Inspect formwork structure before, during and after concreting
• Respond to failure
in formwork structure, fire and emergencies
6.4 Confined
Space Safety Assessor (CSSA)
• A competent person appointed by the responsible person who has undergone and passed the confined space safety assessor course.
• Ensure that a confined space entry permit has been issued in respect of the entry into or work in
the confined space.
• Ensure the description and location
of the confined space is clearly indicated in the entry permit
• Ensure that the
purpose of entry into the confined space is clearly indicated specifying the natural of work or types of work t be carry out
• Conduct gas check prior to entry into confined space and the results of the gas testing of the
atmosphere of the confined space shall be indicated clearly in the entry permit
• Make sure the period of validity of permit is clearly indicated and brief to supervisor
• Conduct regular gas check during the course of work in confined
space.
6.5 Confined Space Supervisor
• A competent person appointed by the responsible person who has undergone and passed the
"Supervise Work in Confined Space Operation"
course.
• Ensuring that confined space worker are briefed in the safety and health precautions to take prior to entry and work
• Authorizing entry into confined spcaces
• Ensuring that confined space workers adhere to entry procedures
• Implementing control and preventive measures to manage all identified hazards are implemented.
• Applying the entry permit and have it endorsed by the Authorized Manager before commencement of confined space work
• Terminating the entry permit after completion of work.
6.6 Working at Height Supervisor
• A supervisor who has undergone and passed "Working at Height course for Supervisor"
• To manage and direct the manner of work at the worksite in accordance with established procedures.
• The carry out WAH join inspection with WAH assessor to ensure all the safety measures and compliance are in place accordance with the WAH procedure.
• Responsible for the safety and health of the workers working at height.
• Ensure all control measures are adhered and implemented effectively on site before submitting the application of Permit-to-Work (PTW) to the assessor for evaluation.
• To inspect all type of fall preventing PPE I appliances and ensure that there are no defects and safe to use.
• Ensure non-conformance is promptly rectified.
• Ensure sub-contractors and workers attend working at daily toolbox meeting and RA briefing.
6. 7 Lifting Supervisor
• Wear brown helmet and fluorescent waistcoat with "lifting supervisor" written on back
• Coordinate all lifting activities
• Ensure that only registered crane operators, appointed riggers and appointed signalman participate in any lifting operation involving the use of a crawler or mobile crane
• All loose lifting gear color coded
• Ensure that the ground condition are safe for any lifting operation to be performed by any crawler or mobile crane
• To supervise all lifting operations and ensure safe lifting
procedures
•
If any crane operator or rigger reports any unsatisfactory or unsafe conditions to him, take such measure to rectify the unsatisfactory or unsafe condition or otherwise
• Provide barricade and warning signs
WMS/METHOD STATEMENT FOR RC STRUCTURAL WORKS
Page 6
6.8
Rigger
• Wear red helmet and fluorescent waistcoat with "Rigger" written on back
• Check the slings to be used for slinging the loads to ensure that the slings are of good construction, sound and of suitable material, adequate strength and free from patent defect
• Ensure that an adequate number of slings is used and that the sling angle is correct so as to
prevent the sling from being overloaded during the hoisting
• Ascertain the
weight of the load which is
to be lifted and inform the crane operator of the weight of the load
• Ensure that only proper lifting gears inspected and color coded are used in conjunction with the sling
• Ensure that the load to be lifted is secure, stable and balanced
• Ensure that any loose load is placed in a receptacle to prevent the load or part thereof from falling during the lifting operations
• Place adequate padding at the edges of the load which come in contact with sling so as to prevent the sling from being damaged
• Report any defect in the lifting gear to the lifting supervisor
6.9 Signalman
• Wear red helmet and fluorescent waistcoat with "signalman"
written on the back
• Ensure or verify with rigger that the load is properly rigged up before he gives a clear signal to the crane operator to lift the load
• Give correct
and clear signal to guide the crane operator in the maneuver of the load safety to its
destination.
7 MACHINERY AND EQUIPMENT
The following machinery shall be used for Reinforced Concrete Structural works:
• Excavator
• Air compressor
• Welding Generator
• Tower Crane (By HDEC)
• Crawler Crane
• Lorry Crane
• Dump truck
• Concrete Pump Truck
The following equipment shall be used for Reinforced Concrete Structural works:
• Electrical breaker
• Pneumatic Breaker
• Circular saw
• Grinding machine
• Concrete bucket
• Diesel engine vibrator
• Rebar cutting & bending machine
• Miscellaneous small hand held tools - provide as necessary
8 MATERIALS
The followings materials shall be used for Reinforced Concrete
Structural works:
• Plywood as formwork
• Reinforcement Bar (Supplied by HDEC)
• Concrete
(Supplied
by HDEC)
• Others materials which applicable
9 PROCEDURES
9.1 General
(a) Toolbox Meeting I
Risk Assessment Briefing shall
be conducted and all personnel have better understanding of safe work procedure before start work.
(b) All works shall be performed
by properly trained and experienced personnel familiar with their respective work
scope.
(c) Subcon shall prepare proper and adequate PPE (safety helmet, safety shoes, hand gloves, safety goggles, safety harness, safety masks, ear plugs etc.) for all employees before
mobilization.
( d) Subcon shall conform to HSE standard while moving machinery and equipment from
yard to worksite.
(e) Subcon shall ensure working area is always in good housekeeping condition.
(f) Subcon's surveyor shall set out the gridline and reference level of the proposed work.
(g) During the course of work, ongoing survey and marking shall be carried out to ensure structural
works constructed according to the design drawing.
(h) Upon completion of the
works,
a joint
survey of the
area and level shall be carried out with main contractor and consultant to confirm that the works are done as per the design drawing
and levels. As built survey for built up structural element will be done for cross checking and record.
(i) All works shall be performed by personnel familiar with their respective scope.
9.2 Lean Concrete Work (For
Pilecap, Ground Beam and Base Slab)
(j) Upon completion of excavation, level and compact the ground at the proposed RC Structure location.
(k) Install side forms around the proposed RC Structure with additional working space along the
perimeter.
(1) Site Supervisor shall check and ensure
the lean concrete level is correct before casting work
(m) Ensure there is extra working
space allowance (extending at least 1 OOmm from the edge of the
RC Structure) allowed during preparation of lean concrete works
(n) Excavator I crane shall use for the casting of lean concrete base.
(o) Pour concrete and
level
smoothly the surface. Wait
24 hours before removing of side formwork
of lean concreting.
(p) Ensure that
workers must be away from the concrete bucket while discharging concrete for the lean concrete.
(q) Ensure
workers involved in the concreting works must wear
proper PPE.
9.3 Survey and Setting
Out - Markingof StructurlaLine on top of Concrete
Surface
(a) Survey controls for the project to be based on a registered surveyor's control points established on the site and must match to existing
plant grids.
(b) Setting out of structural element and
casting level for structures will be carried
out
by subcontractor's surveyor progressively.
( c) Surveyor shall mark the line of the structures on top of concrete surface.
(d) Site Supervisor shall carry verification of structural line (example dimension) prior
to placing of reinforcement and formwork.
9.4 Installation of ReinforcementBar
(a) All reinforcement bar shall
be prefabricated from factory and deliver to site by trailer I
lorry crane.
(b) Reinforcement bar
shall be unloaded to the designated storage area and properly barricade.
(c) Site Supervisor shall identify the required length and sizes of reinforcement bar to be installed for the purpose of shifting and transfer to working area.
(d) After identified, reinforcement bar shall then be shifted to working area by lifting using of crane or by manual handling in buddy
system within personnel capacity.
(e) Identify the reinforcement bar required for pilecap, ground beam, slab and wall rebar. Lay reinforcement bar according to the design and spacing required. Column I pedestal or any others structural cormection
which required starter bar or coupler
shall be installed.
(f) Colunm reinforcement bar shall be prefabricated to the required cage and height as per design at designated storage area and shift
to the installation location for installation.
(g) Installation of column reinforcement bar and shifting of superstructure beam, wall and slab reinforcement bar shall be carry out by crane guided by lifting crews.
(h) Install column reinforcement bar to the starter bar from foundation/stump, considering the concrete cover and lapping length specified in the drawings or specification. If reinforcement bars to be installed needs protrusion as starter bars for the next stage of work, lap length must be based on the specifications and drawings.
(i) For superstructure beam and slab, reinforcement bar shall be shifted and lifted to the working area after the completion of soffit formwork.
U) Identify the reinforcement bar required for each beam and slab and lay reinforcement bar according to the design and spacing required.
(k) To ensure workers would carry fabricated reinforcement bar within their capacity during the installation of reinforcement bar.
(I) Reinforcement bar shall be fixed with galvanizing tie wire to secure it position
(m) Educate workers to plan properly where to position themselves while fixing reinforcement bar in order for them to have sufficient space for body movement
(n) Ensure protruding sharp edge shall be protected.
(o) Ensure reinforcement bar shall not be keep near to the edge of working platform where there is
a risk of falling object.
(p) Site Supervisor shall brief workers on the proper posture and handling of reinforcement bar
(q) Proper working platform such as scaffolding shall be provided for the installation of column, wall and beam rebar if required.
9.5 Installation
and Dismantlingof Formwork
(a) Mark the position of the proposed RC structures on the concrete surface to ensure correct location I
size of the formwork.
(b) Fabricate formwork according to the dimensions specified in the drawing with
appropriate bracing support. Formwork could be made of timber and plywood or steel materials.
(c)
Install formwork for the pilecap, ground beam and slab with proper support.
(d)
Provide binding support to the formwork cage with sufficient spacing.
(e) For superstructure column, formwork will be fabricated into four pieces of form and install to the column location piece by piece.
(f)
If superstructure column I
beam fonnwork cannot be installing by manual handling, crane shall used to lift, install and shift the formwork to the required location.
(g) For superstructure beam and slab, ensure proper soffit support before installing soffit formwork.
U-Jack, timber and GI pipe shall be used as soffit support. A Professional Engineer (PE) shall be engaged to design a formwork structure including falsework if:
> Supporting a slab or beam to be cast that is greater than 300 mm thick
> the structure is greater than 9m in height
> construct in 2
or more tiers
(h) Level of column, beam and slab shall be transferred from the reference level provided by surveyor.
(i) Secure formwork to the concrete surface
I soffit support timber by nailing using concrete nail follow by all necessary support such as tie rods with nuts, inner unit and etc. Ensure sufficient supports and braces at the sides to prevent buckling or movement especially during concrete compaction using vibrators. Conduct inspection before proceed with concrete casting by Formwork Safety Supervisor.
(j) Site Supervisor shall ensure formwork installed must be sufficiently rigid and tight to prevent loss of grout from the concrete at all stages of placing and vibrating.
(k) All holes shall be closed to prevent loss of grout from the concrete during concreting.
(1) Additional support materials such as tie rods with nuts and washers shall be use to secure the
formwork if the RC Structure required large amount of concrete pouring and high pressure during concreting.
(m)
Ensure routine check on the sizes and support of formwork.
(n) Ensure to call for inspection of formworks before concreting works. Any rectification work
shall be carried out immediately if found. Dust or unwanted material
shall be cleared.
(o) For fonnwork or falsework which required PE Design, a joint inspection shall be conduct with PE, Site Engineer and Formwork Supervisor prior to concrete casting with the issuance of Certificate of Supevision(COS) by the PE.
(p) After concreting, formwork shall be removed after attaining the minimum time for curing as per specification or RTO I
RE instruction.
(q) After striking fonnwork, any honeycomb surface and defective or damaged concrete works shall be made good immediately. Also holes formed by tie bars shall be filled with mortar.
(r) To remove protruding or scattered nails after removal of formwork.
(s) Ensure proper housekeeping after striking fonnwork to provide proper access to working area.
9.6 Installation of Embedded Items (Steel,M&E&I)
(a) After formwork in place and before it is fully closed, embedded steel and M&E&I items shall be install before closing the formwork.
(b) Site supervisor shall identify the location of embedded item, required sizes of embedded items and level of embedded items before installation.
(c) Install embedded items according to the design drawing by nailing or using wire to secure it to the inner face of the formwork.
(d) Embedded and M&E&I cast in items shall be inspected by HDEC M&E&I engineers prior to concreting or closing of formwork to ensure it is correctly installed.
9.7
Installation of PVC Water Stop
(a) For basement, underground structures or water retaining structures which required
waterproofing work, water stop shall be installed in between
the construction joint of each stage of concreting.
(b) Water stop used shall accordance to the approval from
WP and SCC.
(c) Provision of kicker of 1 OOmm to l 50mm high shall be allowed for the installation of water stop
(d) Use of G.I wires or other means of securing to secure the water stop at the center of wall where half depth of the water stop shall lay inside the kicker and half depth of the water stop shall be exposed for the next concreting.
(e) If water stop required to be joined for the continuing length, it shall be carry out according to the manufacturer recommendation.
(f) The ends of water stop to be joined are cut square and held in aligmnent. The ends are then
pressed to both
side of a special heated blade until an even, molten bead of Polyvinylchloride appears around the section. The heated blade is then removed and the molten ends pressed fully together.
(g)
Ensure the joint is properly joined and no hole in between the joint.
(h)
Surface of water stop to receive second stage of concreting shall be cleaned prior to casting.
9.7 Concreting Works
(a) The structure to be cast must be inspected and approved by HDEC and WP.
(b) Where a formwork structure is designed by a Professional Engineer, placement of concrete shall not commence unless the formwork structure, including any alteration has been inspected and certified safe for its intended use by a Professional Engineer.
(c) Prior to the placing of concrete, formwork must be cleaned and well wetted and some extra measures shall be taken to protect the concrete during rainy condition.
(d) Placing of concrete to the casting structure shall be carry out in a proper way which does not cause segregation or otherwise impair the quality of the concrete.
(e) During concreting, the formwork system should be regularly monitored by the formwork
supervisor for movement, stability and soundness. The formwork supervisor and any other workers should not work under or in close vicinity of the formwork structure while the pouring of concrete is in progress.
(f) Concrete pump, concrete bucket, excavator or concrete pails in pouring concrete shall be used depend on site condition. When using concrete bucket, a crane shall be used to lift it to the correct location guided by lifting crews.
(g) Chute or extension hose shall be used on narrow and high structure to prevent spillage of concrete.
(h) Place concrete in uniform
layers or in sequence that would prevent cold joints.
(i)
Compact and vibrate poured concrete with vibrators until concrete fully settlement.
U) Ensure no over vibrate to the concrete to avoid segregation between coarse and fine aggregates. (k) Level the surface of the poured concrete to the desired lines and gradient. Finishes shall be in
according to the drawings
and specifications.
(I) Ensure workers involved in the concreting works must wear
proper PPE.
(m) Concrete curing agent shall be applied after the concrete has cured to avoid excessive heat loss and cause crack to the concrete surface.
(n) If concrete surface required surface hardener, it shall be carry
out by others.
Notes:
(a) Trail mixes for the design concrete strength shall be done. Test results shall meet the requirements or specification for concrete.
(b) Slump test shall be done to the delivered concrete and once slump requirement is met, cube samples are to be taken for compressive test on 7u1 & 28th days. Cubes samples are to be treated on a cube tank filled with water till its testing date and to be carefully transported to the approved test laboratory for Compressive Strength Test.
(c) Waterproofing concrete with Xypex Admix-ClOOONF shall be adopted for basement slab, perimeter RC walls and columns, bunker base slab, perimeter RC walls and columns, cable chamber/trench base slab, perimeter RC walls and columns up to below ground
slab/pilecap level.
10 PROGRAMMES
The overall programme shall be prepared base on the construction schedule with input from
HDEC and
sec.
HEALTH, SAFETY AND ENVIROMENT
Subcontractor's workers shall comply with the requirements of this method statement, Main Contractor's Safety Management Plan and Singapore's local authorities.
Subcontractors shall also be required, before starting works, to submit to HDEC safety officer, documentation confirming their compliance with these required requirements. Valid certificates for machinery and equipment and personnel (i.e, site supervisors, machine operators etc) shall also be submitted.
The following items also from part of our safety and precautionary measures:
• PPE: all personnel shall comply with the basic
protective wear of
safety helmet with chinstrap, clear glasses with side shield, safety boots with steel toe lining and long sleeves shirts. Leather hand
gloves, earplugs and safety harness shall be worn as per task specific.
• Lifting Method: All lifting machines and lifting gears to be used shall be tested by third party authorized testing
centre with valid certificates. Only persons who are certificated, licensed, authorized and appointed shall be allowed to operate & work in the area.
• Daily equipment and lifting gears inspection shall be carried out by the operator and lifting supervisor.
• First aid:
Site Supervisors shall inform workers concerning the location of the nearest first aid facilities.
• Tool Box Meeting and RA briefing: Site Supervisors shall conduct daily tool box meeting with all subcontractor's staff and workers to re- affirm the requirement of the risk assessment items.
• Work Permit System: A Work Permit System is also in place whereby all activities to be performed are identified and the safety requirements satisfied before getting approval from main contractor.
• Housekeeping: Site Supervisors and foreman shall instruct and instill in workers the habit of doing daily housekeeping at the end of each working day. All waste and unused materials of different types shall be placed in different bins accordingly. (i.e. do not mix organic with inorganic wastes)
11.1 WORKING AT HEIGHT
subcontractor's workers shall comply with the requirements of Workplace Safety and Health
(Work at heights) Regulations prior to carry out any working at height.
Fall Prevention Plan (FPP) and
Permit-to-Work (PTW) shall be complied
accordance to Main contractors Work at
Height Procedures prior to start any Work at Height (WAH) activities.
All supervisors and workers shall undergo necessary
Working at Height training provided by MOM
approved training provider prior to start any Work at Height (WAH) activities.
11.2
CONFINED SPACE OPERATION
subcontractor's workers shall comply with the requirements of Code of Practice for Confined
Space prior to carry out any work which require entry into confined
space.
Confined space written procedures shall be established for control of entry into a confined space. The written procedures shall include
evaluation of the necessity and the purpose to enter a confined space, risk assessment, measures for eliminating or controlling the hazards, entry permit system, types of atmospheric testing and means to prevent unauthorized entry including the display of warning signs.
All supervisors and workers including assessor shall undergo necessary Confined Space Operation training provided by MOM approved training provider prior to start any confined space activities.
WMS/METHODSTATEMENT FOR RC STRUCTURAL WORKS
Page 17
12 RISK ASSESSMENT As attached separately.
13 APPENDICES
• Lifting Plan of Reinforcement
Bar, Formwork and Concrete Bucket
• Sample of Falsework Support Drawing
• Propping/re-propping and backpropping method
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