This procedure applies to the installation of formwork and the controls required during assembly, erection and final positioning of formwork used in Structural concrete operations.
.1 All formwork activities will be carried out in accordance with the specification.
.2 After studying the structural drawings, the Project Engineer will plan for sizes, numbers and type of formwork to be used in consultation with the Structural Engineer, if required. Depending upon the programme, the number of repetitions will be decided.
External designers may be used for specific systems.
.3 Availability of formwork will be checked with the Procurement Manager and decision will be taken to buy, hire or reuse formwork material.
.4 During fabrication of formwork shutters, all dimensions shall be cross-checked with a view to avoiding corrective action during erection.
.5 Paint reference numbers on all panels to ensure their use in correct positions.
.6 Ensure that the props, shores, waling, bearers, clamps and tie rods are the right size and at the correct spacings. The Formwork designer shall check the falsework system with respect to load imposed on it and design parameters as laid down in the specification.
.7 Check that the falsework is securely braced and is on a firm foundation.
.8 Forms fastened to previously cast concrete must be tightly fixed to prevent grout loss. Cellular foam plastic strips can be used to make a seal.
.9 Check quality of shutter lining, tightness of bolts and wedges, built-in items, inserts and other embedments.
.10 Tie – rod holes to be made in the formwork shall be neat so that they can be patched or plugged later on.
.12 Particular attention will be paid to the rigidity and line of stop ends and joint formers.
.13 Remove all tie-wire clippings and nails, which may stain both the formwork and the concrete.
.14 Ensure that adequate access and working platforms are in place for the concreting gang and that toe boards and guardrails are provided.
.15 A spreader or lifting beam shall be used to prevent distortion when placing formwork.
.16 Adjustable steel props shall be erected in plumb and verticality of props checked using a spirit level.
.17 A prop should not be used if it is bent, creased or, rusted or has a bent head or base plate, damaged pin etc.
.18 Proper release of agent shall be used so that it can be removed without damaging the surface finish of the concrete.
.19 New timber and plywood forms shall be given first coat of the appropriate release agent 36 hours in advance, then a second coat just before they are used. Avoid excessive use of release agent as this can cause staining or retardation of the concrete.
.20 A close watch should be kept on all wedges and fastenings. Make sure that they do not work loose. Grout loss is an indication that some movement has occurred.
.21 When unsleeved tie bars are being used, ease them slightly before the concrete sets, and remove them as soon as it is safe.
.22 Striking the Formwork:
i) Always obtain approval before striking the formwork in the form of Appendix CONC/04/A.
ii) Ensure adequate safety measures while striking formwork.
iii) Cleaning the face of forms shall start as soon as they have been struck.
iv) Good storage is essential to ensure that formwork can be used again.
v) Paint code numbers on them so that they can be readily identified when next needed.
.23 Safety During Formwork Operations:
i) The weights of large prefabricated sections of formwork should be marked on them so that the lifting capacity of the crane at the working radius is not exceeded. Lifting points are usually provided.
ii) If necessary, a spreader or lifting beam shall be used to prevent distortion.
iii) Where lifting is done by the vertical soldiers, check that they are adequately connected to the walings.
iv) Fire extinguishers in working order shall be in close proximity to the stored formwork.
Formwork Method Statement in word format: CONTROL OF FORMWORK