This document provides a method statement for pouring concrete for the base of a treated water tank (TWT) in Sri Lanka. It outlines the materials, equipment, workforce, procedures, inspections, and safety measures for the pour. Concrete will be placed using a pumping car and crane and consolidated with vibrators. Pouring will proceed in 2m layers, maintaining finish levels. Initial curing will begin after set and continue for at least 7 days with wet burlap and plastic sheeting. Safety protocols include permits, PPE, barricades, and appointed safety personnel.

1. EMPLOYER
NWSDB CENTRAL PROVINCE
SRI LANKA
NATIONAL WATER SUPPLY AND
DRAINAGE BOARD
MAIN CONTRACTOR
OTV
VEOLIA WATER TECHNOLOGIES
GREATER MATALE WATER SUPPLY SCHEME
SRI LANKA
METHOD STATEMENT FOR TWT BASE CONCRETE POURING
A 2018/09/18 BHARATHA LK NJ
REV DATE PREPARED CHECKED APPROVED DESCRIPTION
Format :
A4
This document is the intellectual property of
the relevant issuer. It shall not be
reproduced, used or disclosed other than
with the document issuer’s acceptance.
For Employer Approval :
□ Approved □ Comment □ Rejected
Date:
Name:
Signature:
Page 1 of
Sub-Contractor
Document Reference :

2. GREATER MATALE WATER SUPPLY SCHEME
SRI LANKA
METHOD STATEMENT FOR TWT BASE CONCRETE POURING
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TABLE OF CONTENTS
Section Description
1. PURPOSE
2. SCOPE
3. DEFINITIONS
4. REFERENCES
5. MATERIALS
5.1 Ready mix concrete
6. MOBILIZATION OF WORKFORCE & EQUIPMENT
6.1 Construction Plant & Equipment
6.2 Manpower
7. WORKING METHODS / PROCEDURES
7.1 Number of truck mixtures & delivery
7.2 Placing ofconcrete
7.3 Maintaining the finish level ofconcrete
7.4 Pouring sequence and layer thickness
7.5 Concrete consolidation
7.6 Curing of concrete
8. INSPECTION, TESTING & QUALITY CONTROL
9. SAFETY & SECURITY
9.1 General Provisions
9.2 Safety Action Plan
10. ATTACHMENTS

3. GREATER MATALE WATER SUPPLY SCHEME
SRI LANKA
METHOD STATEMENT FOR TWT BASE CONCRETE POURING
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1. PURPOSE
The purpose of this Method Statement is to create awareness of common tasks involved in TWT base
concrete pouring and ensure the execution is in full compliance with Project Specifications & Standards,
Drawings and other related international Standards & Specifications including HSE requirements. This
Method Statement shall be communicated and be understood by all personnel associated with the task
before commencing the activity.
2. SCOPE
This document enumerates the plan activities and execution activities for the concrete pouring in TWT.
Concrete pouring procedure shall be in accordancewith this Method Statement. Supply, placing finishing
and curing for all applications in line with project requirements
3. DEFINITIONS
NWSDB : National Water Supply and Drainage Board
CONTRACTOR : OTV Veolia
SUB-CONTRACTOR : China Eleventh Chemical Construction Co. Ltd.( ELECO)
PROJECT : Greater Malate Water Supply Scheme
CMS : Construction Method Statement
QA / QC : Quality Assurance & Quality Control
HSE : Health Safety & Environment
PPE : Personnel Protective Equipment
RA : Risk Assessment

4. GREATER MATALE WATER SUPPLY SCHEME
SRI LANKA
METHOD STATEMENT FOR TWT BASE CONCRETE POURING
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4. REFERENCES
- Specification for civil engineering works – NWSDB/SBD/Plant & Design – Build: Specification
- TWT Detail Drawings
- ITP & Check lists for concrete works
5. RESPONSIBILITIES
- Responsibilities for ensuring that the steps in this procedure shall be carried out are specified at
relevant steps in the procedure:
 Site Manager
 Construction manager
 QA/QC Engineer
 Site Engineer
 HSE officer
 SK
6. MATERIALS
All Material listed below shall be approved and inspected by NWSDB prior to use at site.
6.1 READY MIX CONCRETE
Grade 35A ready mix concrete will use for the whole structure.
7. MOBILIZATION OF WORKFORCE AND EQUIPMENT
7.1 CONSTRUCTION PLANT & EQUIPMENT
 Mobile crane
 Pump car
 Poker vibrators
 Carpentry / Masonry Tools
 Wooden level pegs

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METHOD STATEMENT FOR TWT BASE CONCRETE POURING
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7.2 MAN POWER
 Site / QC Engineer
 HSE officer
 Foramens
 Carpenters
 Masons
 Helpers
8. WORKING METHODS / PROCEDURES
8.1 Number of truck mixtures & delivery
Total arrange concrete for the pouring process(approximately) = 225 m3
Capacity of one truck mixture = 5.0 m3
Number of trips required = 225 / 5
= 45 Nos
Time assumed for placement of one truck (5.0 m3
) = 15 min
Numbers of truck mixtures per hour = 60 / 15 = 4 truck mixtures
Travel / Loading time for one truck mixtures = 45 mins
Therefore to have continuous supply of concrete at pouring area shall be 5 truck mixtures, 6 truck
mixtures shall be provided keeping one standby
8.2 Placing of concrete
- For placing concrete, pumping car and crane with skip bucket will use. Pumping car having 38
m boom length shall be provided. Concrete will pour with pump car and crane in same time form
the two banks of treated water tank. As per the sketch: 1
8.3 Maintaining the finish level of concrete
- Level pegs(wooden) shall be provided at about 2m intervals to keep top level uniform and
level instrument to be used for verification.

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METHOD STATEMENT FOR TWT BASE CONCRETE POURING
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8.4 pouring sequence and layer thickness
- First the perimeter wall of the sump shall be complete having not more than 500mm layer
thickness. Free falling height shall not exceeded 1.5m
- For base pouring continue with 2m layer wise from a side of base, as per the Sketch: 2
8.5 Concrete consolidation
- All concrete shall be thoroughly consolidated by suitable means during placement and shall
be thoroughly worked around reinforcement and embedded fixtures and into corners of forms.
Concrete consolidation shall be executed with vibrators without displacing the steel reinforcement,
and ensuring that all parts are filled and compacted until grout floats to the surface. Pouring shall be
continuous and fill the whole section, both vertically and horizontally. Vibrators shall be inserted and
removed slowly, at a speed between 80 mm to 100 mm per second, to prevent the formation of voids
inside the concrete.
- Contact between vibrators and any reinforcing rods will be avoided.
8.6 Curing of concrete
Protect freshly placed concrete from premature drying and excessive cold or hot temperature and
maintain without drying at a relatively constant temperature for the period of time necessary for
hydration of the cement and proper hardening of the concrete.
Start initial curing as soon as free moisture has disappeared from the concrete surface after placing
and furnishing of concrete.
Water for curing shall be portable water which shall meet the requirements of NWSDB specification.
Proper water curing shall be achieved by covering the concrete with specified absorptive cover (such
as burlaps) and keeping the cover continuously wet.
Moisture cover (plastic sheet) shall be overlaid on top of absorptive cover with 75mm overlap in
order to retain moisture by reducing the evaporation.
Water curing shall be continued until the compressive strength has reached 70 % of the specified
strength, but not be less than 7 days after placement.
Casting dates will be noted down and 7 days curing period will be assured by construction
supervisors and continuously monitored by QC Engineers.

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METHOD STATEMENT FOR TWT BASE CONCRETE POURING
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9. INSPECTION, TESTING & QUALITY CONTROL (QA/ QC)
- Inspection shall be accordance with approved ITP & Checklist
- Temperature and slump shall be maintained at NWSDB specification limits
- An RFI shall be raised 24 hrs. in advance prior to executing the activity
10. SAFETY & SECURITY
10.1 General Provisions
Protection and safety shall be in accordance with Project Safety Manual and ELECO Safety Manual
approved by OTV / NWSDB. ELECO shall provide temporary fence, barricades, lights and any other
preventive measure according to the approved Safety Manual for personnel safety during
construction. Directions given in manufacture’s MSDS shall strictly followed.
10.2 Safety Action Plan
Where applicable, Permit to Work will be obtained prior to starting the works.
Workforce and supervisors shall be aware of common risks that could be encountered during the
activities associated with masonry works. Necessary warnings, suitable barricades, proper access,
shall be established. PPE for workers are mandatory.
Site Engineer and General Foreman shall arrange all necessarysafety requirements at site and they
will ensure workplace is safe.
Safety Inspector shall ensure that all safety measures are implemented at workplace and
workers/staff are aware of safety risks.
11. ATTACHMENT
Sketch : 1 , 2
Annex 1: Risk Assessment

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METHOD STATEMENT FOR TWT BASE CONCRETE POURING
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SKETCHES
SKETCH: 01

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METHOD STATEMENT FOR TWT BASE CONCRETE POURING
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SKETCH: 02