Method Statement for Concrete Works

Scope

The method statement for concrete works is to explain the systematic procedures, arrangements and safety measures, which ought be followed during Placing, curing and rectification of concrete works. Contractor shall be accountable to comply with all work and safety stipulations/measures as stated in this method statement.

Work force

• Site Engineer
• Safety Officer
• Site Supervisor
• Surveyor
• Equipment Operators
• Masons
• Carpenters
• Steel Fixers
• Helpers

Equipment

• Concrete pump
• Concrete Mixer Truck/Transit Mixer
• Vibrator (Poker/needle or surface)
• Crane(if required)
• Bucket(if required)
• Power Trowel(if required)
• Air compressor
• Survey equipment (Total station, auto level etc.)
• Other hand operated tools

Personal Protective Equipment

• Hand gloves
• Ear plugs/Earmuffs
• Safety glasses
• Safety vest (high visibility)
• Hard hats and safety shoes

Responsibility

Site Engineer

The Site Engineer is ultimately responsible for work execution and quality/safety management. The Site Engineer serves as a liaison between the Client and the Contractor. The site engineer must also ensure that the Works are completed and maintained in accordance with the provided specifications and approved method statement. The Site Engineer is responsible for the establishment and promotion of process plans by managing all construction manpower and equipment, as well as resolving technical issues and providing support, preparation of an execution plan as well as a quality/safety plan. He must ensure schedule adherence in accordance with the process plan.

Safety Officer

The safety officer is responsible for developing an execution plan as well as a quality/safety plan. Also The safety officer monitors compliance with the safety measures in the schedule. He inspects the tools, tackles, and equipment used in the activities and ensures proper housekeeping before and after the activities. On a daily basis, the safety officer provides proper instructions to the workers in handling the job.

QC Engineer

The QC Engineer is responsible for reviewing and verifying the documentation for the Inspection Request (IR) submitted by the Site Engineer before submitting the same to the client for inspection. If the work doesn’t comply, he is allowed to reject it and submit an observation report. Engineer must liaise with the site engineer and client representative during daily inspections to ensure that the material is kept correctly and free of damage before it is unloaded.

Site Foreman

Site foreman is responsible for supervising the execution of the work at site and ensure that it is being done as per approved project drawings, specification & work procedure. He also Ensures that manpower and equipment are properly distributed. He coordinates with other construction team working adjacent to his location of work and also conducts job safety analysis(JSA) to ensure that each member of the crew is aware of the hazards. He is responsible for preparing and submitting the daily report.  

Method statement for concrete works

Preliminary Activities

• The work area shall be cleaned and leveled. 
• A survey layout drawing must be delivered to the client for review and approval. Site measurements, levels, and benchmarks will also be marked in accordance with the profile drawings.
• All personnel entering the site must have completed a site safety induction.
• Prior to deployment on site, all equipment and tools must be inspected.
• The Engineer is responsible for ensuring that all necessary permits are secured and that work begins in accordance with the precise guidelines outlined in the permit.
• Access to site shall be studied and proposal shall be submitted for approval. All working spaces will have sufficient lighting during nighttime construction.

Execution methodology

• Site preparation
  • Surveyor shall mark the permanent reference points for structural concrete levels. Also the grids shall be established as offset from datum points.
• Formwork
  • In order to construct walls and columns, prefabricated panel modules with timber beams and steel walers will be used. To construct circular columns two half shells with steel faces will be used.
  • Formwork for flat surface like slabs will consist of smooth faced marine graded plywood or steel panels along with proper supports.
  • Forms will be coated with approved formwork release oil, where necessary before the Form is placed.
  • All corners will be positioned 90 degrees according to the drawings and the formwork will be erected in line and level with them.
  • To prevent cement Slurry from leaking out of plywood joints, plywood joints must be protected. 
  • A formwork inspection will be performed before steel reinforcement is installed to confirm that the dimensions and locations of structural members are in accordance with the approved drawings.

• Steel Reinforcement (rebar/dowel/mesh) and embedded item
  • An approved supplier will supply steel reinforcement and dowel bars cut-and-bent to the shapes shown on approved drawings and per approved bar bending schedules.
  • In order to determine the effectiveness of the reinforcement, tensile, rebend, and bend tests will be conducted by an independent Testing Laboratory prior to the installation of any reinforcement for each supplier, and the results will be submitted to the Engineer with the mill certificates. Prior to pouring concrete, reinforcement will be cleaned to ensure that no loose rust, scale, oil, or grease is present.
  • Rebars and dowel bars will be fixed according to approved shop drawings and secured with mild steel tie wire so that they remain in their proper positions.
  • For proper overlap with the consecutive bar, rebar will be extended horizontally and vertically as indicated on drawings.
  • For steel fixing, spacer blocks will be made of approved concrete mix designs or approved plastic spacers will be used.
  • A minimum clear space will be maintained between reinforcement and formwork by placing spacer blocks horizontally and vertically to hold reinforcement in position.
  • The embedded items will be placed according to the approved drawings, including anchorage bolts and plates.

• Concrete works
  • All waste materials including water will be cleared by using compressed air immediately prior to the placement of concrete. 
  • Ready-mix concrete will be used as per the specified grades.
  • Chutes are often used to transport concrete from higher to lower elevations. The gradient should be constant and steep enough to allow concrete of the required slump to flow continuously through the chute without segregation. 
  • When a mixer truck cannot get near the formwork, boom pump(36m, 42m & 52m), stationery concrete pump with liners, dump truck or wheel barrow will be used to transport the Concrete. 
  • Concrete pump will be positioned on leveled and solid ground and the area should be free of obstructions. 
  • Samples from each batch of concrete will be arranged and sent for required lab tests and the respective reports to be submitted to Engineer in-charge.
  • While casting substructures, position the concrete mixer’s chute or the hose of the pump to pour the concrete into one end of the form. Pour the concrete from one end to other. To consolidate the concrete, vibrators will be used. After filling the form, tamp wet concrete and level it with a wooden or aluminum edge.
  • While casting a wall, beginning from a corner, fill the form and move forward, allowing the concrete to flow down. Consolidate by using vibrator. Tap the formwork externally frequently to remove any air pockets.  
  • While casting a column, pour wet concrete into the formwork with concrete pump. Tap the external sides of the formwork frequently to remove any entrapped air.
  • While casting a slab, fix suitable timber or metal edge/intermediate leveling strips with 3-4m interval as to be support for the compaction and adjust the height as per the required level. Position the transit mixer’s chute or the hose of the pump and commence the pouring ready-mix concrete onto the formwork. Use vibrator to consolidate the concrete throughout. 
  • Once the concrete has been placed and finished, fresh concrete will be cured least for 7 days. The exposed horizontal surfaces of fresh concrete will be covered immediately with polyethene or tarpaulin sheets. Similarly, after the form work is removed, vertical concrete surfaces on columns and retaining walls will be covered with wet Hessian cloth.
• Removal/Stripping of Formwork
  • All formwork will be carefully removed without any damage to the concrete. 
  • After removal of formwork, concrete surfaces will be inspected visually and all repairable defective areas of structural members will be patched immediately. 
  • The stripped formwork will be cleaned prior to the next application.
  • Minimum stripping of time for RCC members should be as follows;
    • Walls, columns and vertical faces of structural members – 1day
    • Removal of props beneath slab and beam soffit spanning up to 4.5 m – 7days 
    • Removal of props under beams and arches spanning up to 6 m – 14days