CHAPTER 3 FORMWORK

CHAPTER 3: FORMWORK

FORMWORK What is Formwork? ď ą A mould or box into which wet concrete can be poured and compacted so that it will flow and finally set to the inner profile of the mould.

FORMWORK Also known as shuttering Cost can be as much as 1/3 or more of total cost of concrete work. Have to be designed so that they are practical and economical in

manufacture, construction and use. Must fulfill the following requirements:  Strong enough to support the load of wet concrete  Must not deflect under load (concrete, workers, vibrators, barrows)  Accurately set up and tight enough to prevent loss of fine materials  Must be of correct shape and size  Designed and constructed so that erection and dismantling can be done orderly, simple and does not cause damage to concrete or themselves.  Sections size designed so that can easily be handled, lifted into place and transported.  Made to fit and fasten together with reasonable ease  Can be handled safely

FORMWORK MATERIALS

 TIMBER  one of the most suitable materials because it has the flexibility to be formed  Usually used not more than 4 to 6 times (in situ)  But in factory production may be re used 20 times  In in situ work, plywood can be re used about 30 -40 times if reasonable care is taken  STEEL  Easily be produced as standard units of suitable sizes  Quickly be erected, dismantled and can be used greater times more than timber formwork.

FORMWORK COLUMN FORMWORK

a vertical mould  located against a 75 mm high kicker/plinth to: • accurately position the formwork • prevents loss of grout from bottom edge  panels strengthen with horizontal cleats or vertical studs  constructed to full height, allowing incoming beam forms 

COLUMN FORMWORK (TIMBER) for rectangular columns, formwork consists of 4 shutters or panels  nailed securely and held together by a series of timber yokes  thickness of board varies between 25 to 50 mm 

FORMWORK COLUMN FORMWORK (TIMBER)

FORMWORK COLUMN FORMWORK (TIMBER)

FORMWORK COLUMN FORMWORK (TIMBER)

FORMWORK COLUMN FORMWORK (STEEL)

STEEL     

for rectangular columns, formwork consists of 4 shutters or panels Very strong and able to carry heavy load Easy to fixed Uniform size and surface can be used for a very long time

FORMWORK COLUMN FORMWORK (STEEL)

FORMWORK BEAM FORMWORK 

beam sides are generally built up of boards nailed to battens.

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bottom should be thicker an made from single width of board

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during erection, the bottom are first place in position between column boxes and supported by props.

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sides are then placed in position and nailed to the edges of the bottom piece and secured to the column boxes.

FORMWORK BEAM FORMWORK

FORMWORK BEAM FORMWORK

FORMWORK BEAM and SLAB FORMWORK

FORMWORK SLAB FORMWORK  25 – 32 mm decking normally required  thinner decking requires closer and less economic spacing of joist  plywood used varies from 12 – 20 mm thickness  adjustable steel props or tubular steel scaffolding may be used instead of timber props to support floor decking

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FORMWORK STAIR FORMWORK ď ą The formwork for stairs is usually ply on timber, apart from jobs that have many repetitions or curves, in which case purpose made steel forms are used. ď ą The stair is supported by the landing at the top, which is in turn a continuation of the main floor slab. The stair and landing were poured at the same time as the main floor slab.

END OF CHAPTER 3