The purpose of this method statement is to define the procedure for the preparation and construction of Cast in Place Concrete Works for water tank in accordance with the requirements specified in the relevant specifications, procedures and drawings, considering safety and quality of the work activities.
Project manager and engineer shall ensure that project works in his zone are carried out in accordance with company policies and in accordance with the requirements of the project quality plan.
He shall also ensure that all the equipment required to execute the works according to the construction program are available, in good condition, and provide any additional equipment that might be required.
PM is responsible to co-ordinate with the construction manager, project engineer, safety engineer, Foreman and Surveyor for a safe and proper execution of the works. To guide specific attention to all safety measures in co-ordination with the safety officer/engineer.
Following tools shall be arranged for Construction Of Cast In-Situ Concrete Water Tank.
- JCB
- Dump Truck used for disposal of debris
- Truck Load Mixer (Concrete supplier)
- Vibrators
- Concrete Pumps
- Masonry tools
Method of Construction Of Cast In Situ Concrete Water Tank
Surveyor to complete markings, gridlines, level and lay-out of concrete blinding for water tank location.
Excavation works are carried out based on the issued for construction drawings and specifications.
Complete the termite control application based on the manufacturer recommendation and product specification and same procedure apply on the tie beams and pile cap with approval by the consultant.
For Concrete Blinding – same procedure and material to follow on the blinding for Tie Beams.
Apply the water proofing as per drawings and the procedure for application of water proofing is based on the manufacturer recommendation and product specification with approval by the consultant.
Provide protection screed as per issued for construction drawings and material approval by the consultant.
Surveyor to complete markings and lay-out of water tank location.
Steel fixer will fix the reinforcement in accordance to the drawings issued for construction. Provide concrete covering for the reinforcement based on the approved drawings. Submit the inspection request prior to fix the formworks.
Install the water stop as per drawings and approval by the consultant.
Check the Plumbing Pipe Sleeves for water tank and other MEP sleeves as applicable according to the coordination drawings. The contractor should not fix the formworks without the approval from QA/QC and consultant and inspection request to be signed by both parties.
Clean the area and remove waste materials prior to fixing the formworks. Formworks shall comply with relevant specifications and standards. Submit the work inspection request after the formwork installation prior to pouring the concrete.
Now perform the pouring of concrete on the water tank using concrete pump after the consultant approval of the previous activities.
Arrange and use enough vibrators during concreting works.
Provide necessary curing and removal of formworks for concrete water tank as per tender specifications and apply the waterproofing as per the applicable procedure. Clean and remove all debris prior to start the waterproofing application.
Construction of Water Tank at Basement Floor
Construction of water tank wall shall be done as per the approved drawings and layout of Water Tank walls. The location of the water tank wall shall be marked out by the surveyor in accordance with the approved drawings.
Side Shutter
The day after casting concrete for the raft slab cleaning of reinforcement and the water bar, surveyor shall mark out the wall and column alignment and the steel fixers shall fix the steel reinforcement.
When the steel is inspected and MEP clearance is received, the carpenters shall fix the side shutter in place. Shutter shall be fixed using waterproof tie rods for walls. After a final inspection of the formwork and upon receiving clearance from the Consultants the concrete shall be casted as per the approved shop drawing.
Casting Water Tank Walls and Column
During concrete placement, care shall be taken not to lose any ingredients from the concrete, any type of segregation, and the displacement of the reinforcement.
Concrete shall be deposited in uniform layers from the bottom to the required level and shall be consolidated using vibrators and pokers. Care shall be taken to avoid segregation. The maximum depth of each layer shall be restricted to 300 mm.
Curing of Concrete
Once the concrete has set curing shall be started and shall be maintained for 7 days
Casting of Roof slab
The roof slab of water tank shall be cast with the basement roof slab
Water Proofing
Once the curing period of walls is completed, The waterproofing system shall be applied to the external face of the water tank in accordance with the manufacturer’s recommendations and the applicator’s approved method statement
Internal Finishing
Internal finishing shall be as per the Specification and manufacturer’s recommendations and the applicator’s approved method statement.
Testing of Tank for Water Tightness
The water tank shall be tested for the water tightness as per the specification requirements and procedures.
Backfilling
Once the water proofing of external face of water tank is inspected and approved by consultant the backfilling around water tank shall be carried in 250mm thick layers and its density shall be tested. The backfilling shall carry out up to the required grade level as per the drawing. During backfilling the anti termite chemical shall be sprayed after every 1 meter layer of backfilling.