The purpose of this civil work method statement is to lay down the systematic procedures for the various activities required for reliable formwork to ensure that all works are carried out according to the designed drawings and Technical/Contract specifications.
Scope of this method statement shall apply to all the Formworks/Shuttering at a construction project.
The method below shall cover the materials required for the formwork of various structures, the fabrication and installation to ensure the finished work is as per the approved design drawings and project specifications.
Together with this Method statement, the following documents will be read in conjunction:
- The Technical Specification for structural concrete from the contract documents
- Approved drawings for construction
- Site Instructions
Applicable Standards and Codes:
ACI 117 Standard Specification for tolerances for concrete construction and materials.
ACI 301 Structural Specification for Structural concrete.
ACI 318 Building code requirement for structural concrete.
ACI 347 Recommended Practice for Concrete Formwork.
Roles and Responsibilities
The following Personnel are responsible to ensure the implementation of this formwork method statement:
The Project/Construction Manager for the Project shall be responsible for carrying out the works in accordance with this Method Statement.
Quality Assurance and Quality Control (QA/QC) Engineer is responsible for implementation, maintenance and revision of this form work procedure as and when found appropriate. He is further responsible for the doing inspections, preparation and maintenance of quality records as required by this method statement.
The Land Surveyor shall be responsible for the setting out all foundations and access roads and for controlling layer thicknesses.
The Site Engineer and Site Supervisor shall be responsible for planning and carrying out the physical preparations for the formwork activities.
The Carpentry Foreman shall be responsible for the installation, positioning, aligning, and plumbing of all formwork and to ensure it is secure and strong to support wet concrete.
The Safety Officer shall be responsible for monitoring and ensuring that all activities are carried out safely in accordance with the Health, Safety and Environmental requirements as stipulated by company HSE policy, the safety requirements by the client and the OSHA stipulation.
Necessary Equipment and Tools
- Crane
- Circular saw machine
- Generator
- Air Compressor
- Crane truck
- Spanners
- Hand tools
- All Plant and Equipment will be provided by Caspian Limited
Health and Safety Requirements
Conditions and precautions listed in the project specifications and project HSE plan shall be followed as minimum.
All staff involved in the project shall be inducted on the safety, health and environmental issues associated with the form work activities.
Appropriate safety signboards, barriers and lighting and other safeguards shall be provided as required by the nature of and location of the works.
All operations shall be carried out in accordance with the safety requirements.
All field personnel will use PPE as per the requirements like safety shoes, helmets, cover all, dust mask etc.
Standard Safety Instructions:
Housekeeping and disposal of special waste as per the environmental management plan.
General Safety Measures as per the health & safety plan.
Drugs & Alcohol control as pet the drug & alcohol management plan.
Formwork Materials
Formwork materials for the project shall be both steel panels and timber formwork.
Timber formwork
Timber formwork will be made of marine plywood which will be sized to suit the structure.
Plywood will be supported by timber (either 2×4 or 2×6) depending on the load to be supported.
Formwork from this materials will be cut, shaped and sized on Site.
Both Plywood sheets and timber will be sourced locally.
Steel Panel formwork
The steel panel formwork are in-house materials that will be provided as per the site requirements.
Formwork Methodology
Preparatory works
Obtain relevant approved construction drawings from main contractor.
All materials for formwork brought to project site shall be visually inspected for straightness, finish and defects prior to use.
Set out the locations, centre lines and levels for formwork along with reference lines.
Prepare necessary formwork panels to the required dimensions and sizes.
Structural calculations of structures carrying heavy loads will be submitted to the consultant for approval should the Client or the Consultant see the need to do so.
Coat formwork surface evenly and thinly with release agent like form oil etc.
Work Methodology
Erect the formwork by providing sufficient props and struts including necessary bracing.
Use scaffolding and staging arrangements, where necessary.
Seal gaps in formwork to avoid leakage of concrete.
Ensure checking for the required shape and dimensions as per drawings.
Submit Request for Pre-Concrete Inspection for joint inspection with consultant.
Striking formwork shall be done in accordance with ACI 347.
Side forms for mats supporting no load other than lateral pressure of plastic concrete may be removed after 12 hours of cumulative curing time.
The earliest loading of foundations and slabs-on-grade shall be no sooner than the completion of 7 day curing and after achieving a minimum of 75% of the specified 28 day strength.
Tolerances for the Form Work
Variation in dimension between the centers of any two anchor bolts within a group shall be equal to or less than 3 mm.
The variations in dimensions between the centers of adjacent anchor bolt groups shall be equal to or less than 6 mm.
Variation in elevation of the tops of anchor bolts shall be equal to or less than +/- 6 mm.
The accumulated variation in dimension between centers of anchor bolts groups along the column line through multiple anchor bolt groups shall be equal to or less than 6 mm per 30.5 m but not to exceed 25 mm.
Variation in dimension from the centre of any anchor bolt group to the column line through that group shall be equal to or less than 6 mm.
All bearing devices (plates, nuts, washers etc.) shall be installed to within +/-3 mm in elevation relative to the established grade.
Elevation of slab on grade shall be within 19 mm of drawings.
Cross sections of slabs shall be within +25 mm and -19 mm of drawings.
Offset of adjacent formwork facing material shall not exceed 12 mm.
The values stated above are minimum requirements.
In the case of structures which are especially sensitive to settlement or for built-in items of plant, tighter tolerances may be necessary.
Formwork General Instructions
Use formwork which is rigid and closely fitted, with sufficient strength to support wet concrete.
Ensure that centering plates, planks or plywood are properly cleaned.
Effect proper check for line, level and plumb before starting concreting activity.
Shuttering to be checked in stage wise, i.e.
- beam bottom – alignment, level and rigidity of staging to take the load.
- Beam sides.
- Slab shuttering & levels.
- Fixing of side supports, bhida, etc. for rigidity.
Special care should be taken to check column supports at junction of beams.
Position of pockets and insert to be carefully placed and checked before placing the concrete.
Take care to apply suitable form release agent before the placement of reinforcement and after proper cleaning of form work.
Use magic tape for gap filling where necessary.
Provide extra supports at joints of wall plates beam bottom, proper care must be taken to prevent bulging of centering.
Ensure that proper supporting system has been adopted for external beams to prevent bulging.
Leave slab form work undisturbed till concrete gains 70% of required strength.
Take care not to damage the concrete while striking the centering off.
Removal of shuttering in view of time period should be as detailed below.
| a) | Walls, columns and vertical sides of the beams | 24-48 hours |
| b) | Slab | 3 days |
| c) | Beam soffits | 7 days |
| d) | Removal of props under the slab
Spanning up to 4.5 m Spanning more than 4.5 m |
7 days
14 days |
| e) | Removal of props under beams and arches
Spanning up to 4.5 m Spanning more than 4.5 m |
14 days
21 days |
After deshuttering all the material should be properly staked and cleaned for next repetition of the formwork.
Provide plywood boxes for small cutouts / ducts / openings in slab.