Method Statement for Slab on Grade
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Method Statement for Slab on Grade

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Method Statement for Slab on Grade

Purpose.

The purpose of this method statement is to set a standard work process for Slab on Grade and its related activities to ensure that all the necessary works are to be carried out in a safe and systematic manner based on the project requirements. 

Scope of work.

The scope of this method statement is to provide as guideline to ensure the fundamental checks and good working practices during Slab on Grade Concrete with respect to Project specification, Approved drawings, Material submittal, method statements
This activity should be performed with strict compliance and implementation of Safety Requirements & Procedure, standard practices, and project specifications to complete the work.

Materials and tools/ equipment.

Materials.

  • Approved Concrete Mixed Design
  • Steel Reinforcement
  • Polyethylene Sheet
  • Curing Compound         
  • Spacer sheet

Tools and equipment.

  • Concrete Trucks
  • Pumps (Mobile)
  • Electrical Vibrators
  • Concrete Thermometer,
  • Ambient Temperature Thermometer
  • Testing Equipment
  • Water
  • Electrical Supply

Procedures.

Preparation.

Prior to commence the stated concreting works, the Project Engineer shall ensure that the following have been completed and signed off by the Consulting Engineer.
  • All backfilling levels have been adjusted as per approved shop drawings.
  • Compaction test for the backfilled area is approved and the required test passes the 95% of maximum dry density.
  • Anti-termite was applied for the intended area to cast.
  • Polyethylene sheets 1000 gauge have been laid and over lapped 150mm by tape.
  • Spacer sheets were fixed properly on the side of the adjacent vertical elements to form the joints around the slab on grade.
  • Only concrete cover blocks below the reinforcement will be used.
  • The approved method statement is understood by all relevant personnel
  • The concrete design mix has been approved.
  • Trial mix report has been approved.
The project Engineer shall ensure that necessary MEP clearance/Statutory Authority approvals have been obtained. 

Reinforcement.

  • Site engineer will ensure the survey points are properly marked to ensure precise level of slab on grade concrete.
  • Steel reinforcement installation for Slab on grade will proceed as per approved structural drawings.
  • Ensure all reinforcement details are followed (no. of bars, spacing, concrete cover and the required steel overlapping).
  • Main steel reinforcement layers and additional reinforcement shall be fixed as per approved shop drawings and code of practice.
  • Ensure that all reinforcement is correctly tied using binding wire to maintain their location and stability during concrete casting.
  • Site Engineers shall check the levels, fixing and bracings for the chairs to ensure that the top slab level and safe working loads for top layers is not exceeded.
  • Ensure that all Embedded MEP services are installed, inspected, and approved. MEP services will be fixed and levelled/sloped as per approved MEP drawings (drainage pipes, floor drains).
  • Approval for MEP inspection request will be obtained before casting the concrete.
  • Surveyor shall check/inspect the top reinforcement level during the fixing process to ensure the slab on grade top level is correct.
  • Check dimensions and levels as per approved drawings.
  • Cleaning of the area shall be done by air compressor and hand tools during working stages for the slab on grade to avoid accumulation of debris and rubbish on slab.

Formwork.

  • All Plywood to be used will be in good condition.
  • The ASGC Surveyor shall mark the locations and level of shutter borders as per approved concrete layout
  • Ensure enough stiffeners and sufficient support to be provided for the side shutter to avoid unacceptable deformation for concrete surface at slab edge and construction joint (if required).
  • Alignment and Plumpness of side shutter to be maintained

Construction and control joint.

  • Construction joint shall be provided as per approved shop drawing (or 20mX20m with saw cut joints at 5m center if not mentioned otherwise)
  • The ASGC Surveyor shall mark the location construction joint as per approved drawing.
  • If required, concrete stopper shall be provided in the construction joint.
  • Upon completion of casting, as soon as concrete can be cleanly cut and before shrinkage cracks can form, saw cut joints shall be carried out.
  • Make saw cut joints of 5mmX25mm, generally occur in column lines and on intermediate line resulting approximately square section (not exceeding 5m in length and width if not mentioned otherwise)
  • Joints shall be clean prior filling with approved joint filler
  • Filling of joints with approved joint filler, not less than 21 days after casting 

Placing concrete.

  • Ensure that the concrete design mix has been approved.
  • Trial mix report has been approved.
  • The concrete shall be in accordance with the approved Slab on Grade design mix 
  • Sufficient lighting will be provided during the casting.
  • Concrete temperature shall not exceed 32o C during concrete pouring.
  • Concrete trucks shall be checked by QA/QC representative at checkpoint prior to release to the site.
  • Temperature and slump shall be checking to ensure the integrity of fresh concrete.
  • All surplus waste concrete shall clear away.
  • The concrete shall be vibrated; Spare vibrator shall be kept at any case of emergency.
  • The surface level of concrete shall be marked by pegs or tape over exposed reinforcement bars. The Project Engineer shall ensure that the top surface is level.
  • The concrete finishing shall be undertaken using power float machines. The approved curing compound will be applied to concrete surface just after completion of the power float process.

Concrete sampling and testing.

  • Slump of concrete will be measured on random basis
  • Temperature will be monitored and recorded.
  • For every 100 cu. meters delivered, 1 set of 8 cubes shall be taken for compressive strength test: 3 cubes for 7 days, 3 cubes for 28 days & 2 cube spares. 
  • Testing of cubes will be done in approved third party laboratory.
  • The slump, temperature of arriving concrete and cubes will be taken by Concrete Supplier Technician

Curing.

  • As soon as finishing of concrete done, cover the surface with polythene sheet to reduce temperature built-up
  • Curing shall be done with water and covered with polythene sheeting 
  • Curing shall be continued for 7 days or use Engineer approved curing compound application on the concrete surface as soon as final finishing of concrete is done 
  • Ensure surface water has been disappeared before application of curing compound
  • Apply curing compound uniformly by using spray or roller

Control.

  • To acquire the specified requirements, follow the Inspection and Test Plan (ITP) in this method statement that will serve as a guideline for the Construction Team and QA/QC Team in monitoring, inspection, and testing.
  • A checklist for this activity will be used by the Construction Team to identify each point to be inspected at every stage of the activity. 
  • The QA/QC Representative will verify the compliance and completeness of the work by inspecting it and reviewing the same checklist.
  • Refer attachment of this method statement for the ITP. 







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