This method statement will help to describe the procedure to for parapet wall / roof construction works, that ultimately will ensure that the work is planned and performed in accordance with project technical specifications and drawings.
The project manager will be responsible for overall activities. The work will be carried out under the responsibility of Construction Engineer & Project Engineer. Quality Engineer QA/QC will be responsible for documentation and all inspections in accordance with project specifications and PQP. Safety Officer will ensure that all the activities are carried out in accordance with the relevant HSE regulations and HSE plan. Foreman will be responsible for achieving the labor productivity.
Health & Safety Requirements
All safety requirements as per project hse plan will be followed. The works will be carried out by experienced operatives who will be supervised during the whole of the works.
Only experienced trained operatives will operate the equipment. Only authorized personnel will be allowed into the work area. All personnel within the work area will wear the appropriate PPE (EYE protection, Ear protection, Inhalation protection and anti vibration gloves).
Statutory examinations will be carried out on all equipment with records kept. Only authorized-trained operatives will be permitted to drive any plant or vehicles and mount abrasive wheels on company machines.
Tool box talks will be given to all operatives covering the following topics:
- Protection of the eyes
- Protection of the skin
- Vibration
- Control of Dust Fumes
- Abrasive wheels
- Control of Noise
Tools Tackles & Materials
- Air Blower
- Angle grinder or disc cutters
- Jack hammer
- Hand Tools
- Plywood Cutting Machine
- Wheel borrow
- Hand shovel
- Hammer
- Concrete Transit Mixer As per pace of pouring
- Concrete Pump 01 No. + 01 No. Standby
- Vibrators 06 Nos + 03 Nos Standby
- Hand Tools As required.
- Concrete Slump Cone & Accessories 01 Set
- Thermometer 01 No. (Digital)
- Cube Moulds & Accessories 06 Nos for every 40 cubic meter of Concrete
Sequence of Parapet Roof Construction Work
Rebars:
Rebar cutting, bending and tying will be based on the Contracts / Shop Drawings. Sketches may be developed at site as identified by Site Engineer for better understanding of the Rebar Installation sequence.
Delivery Notes, Mill Certificates. Steel Origin, Supplier, Manufacturer and other details of all delivered steel consignments will be checked on Site. The records will be available for consultant reference or any future use.
Install rebar’s accurately in position and secure against displacement that might be caused during concrete pouring.
Ensure all embedded items are fixed accurately at required locations and secure tightly against any possible displacement. Any modification done during the installation embedded items shall be indicated in the Check sheets as required.
Embedded items shall not be supported by Welding to Rebar.
Lapping and chairs shall be provided as per the approved drawings.
For every 100 tons in each shipment two samples of each bar shall be tested as per specification.
Formworks
Formwork will consist of traditional 18mm Marine plywood faced Shutters.
Based on the drawings requirements, the Carpenters will fabricate suitable panels and erect in place.
Construction of formwork will be to the dimensions, shapes and sizes required to obtain the accurate alignment, location and plumb of the finished structure.
Formwork will be installed ensuring that the shape, size, alignment, level and any other irregularities are maintained within the specified tolerances before and after concrete placement.
Concrete Placement Prerequisites
Concrete placement can only commence upon approval of Inspection request by the Client / consultant. Request for inspection shall be submitted only upon approval of QC Engineer and at least 24 hours before the casting schedule.
Ensure that all embedded items required are installed and secured at their correct location and levels.
Ensure that all required inspections are performed.
Ensure concrete is placed and compacted in its final position within 2 hours of addition of water to the mix.
The required thickness shall be fixed by providing pre cast concrete spaces and casting level shall be fixed by providing 20mm x 20mm wooden strips on two sides of forms top opening as per the approved plan & specifications and the approved method statement.
Concrete Placement Procedure
Prior to start the walling concrete works the reinforcement, cutting, bending and installation shall be completed as per the specifications for civil works concrete and reinforced concrete and approved by the consultant. It is also assumed that the formworks have been completed as per specifications and approved by the consultant.
Concrete delivered to site will be as per the approved design mix and checked for slump and temperature. Concrete temperature when discharged in the formwork shall not be more than 30 degree Celcius.
Structural concrete works can only commence upon completion of the formworks and reinforcement activities. Inspection request for pre concreting checks shall be submitted to Client / Main Contractor.
Expansion, Contraction, Isolation, Control and construction joints will be located as shown on the drawings.
Concrete placement sequence will be planned in a manner so that to have minimum repositioning of the truck mixer or concrete pump.
Adequate number of vibrators, pokers, Hessian cloth, polythene sheets including standby will be ensured.
All safety precautions will be followed as per the approved project HSE plan.
Concrete Testing Procedure
Testing of concrete for temperature and workability shall be carried out at the site before discharge. After the concrete meets the required temperature and workability cube sample shall be prepared. An area shall be designated near the pouring area for testing and for casting of cubes. We shall deploy one technician with one labor for this work or as per the site requirement.
Six cube samples shall be taken for every 100 cubic meter of concrete for compressive strength test. Additional one sample each set of cubes may be cast to carry out any additional testing requirement if any or as directed by the Consultant. These cubes sample shall be removed from the moulds on the following day and shall be transferred to the approved independent laboratory.
Concrete Finishing Method
The movement of persons on the placed wet concrete shall be avoided as far as possible. Once the concrete surface is touch dry the top surface shall be provided with rough in finishing works. The finished area shall be covered with polythene sheet to avoid rapid hydration. As top of the RC parapet walls is supposed to receive roof slab, contractor shall provide rough in finish as instructed by the consultant engineer.
Concrete Curing & Protection
Curing of the concrete will began immediately after finishing of the concrete surface and in line with the requirements. By covering polythene sheet immediately after finishing.
Horizontally, after final set has taken place i.e, after 8 to 12 hours, the polythene sheet will be replaced by wet Hessian cloth and covered with polythene sheet. The Hessian cloth shall be kept wet for at least 7 days.
Vertical Curing Method:
Inspect the curing operation effectiveness regularly to avoid any drying of the placed on top of the covers.
Ensure damage is occurred to the polythene sheets by the timber pieces.
All vertical surfaces shall be applied with membrane of curing compound immediate after removing shutter
Quality Control
Steel inspection shall be done prior to start of the shuttering works and MEP installations. Final inspection to be done prior to pouring of the concrete.
Upon completion of the day’s work all tools shall be properly cleaned and kept maintained for future use. Site shall be cleared immediately of all debris and wastage. Importance shall be
given for housekeeping upon completion of all works.