define formwork

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define formwork..

Answer / hammad shah

Formwork is the term given to either temporary or permanent
moulds into which concrete or similar materials are poured.
In the context of concrete construction, the falsework
supports the shuttering moulds.

Formwork comes in three main types:

1. Traditional timber formwork. The formwork is built on
site out of timber and plywood or moisture-resistant
particleboard. It is easy to produce but time-consuming for
larger structures, and the plywood facing has a relatively
short lifespan. It is still used extensively where the labor
costs are lower than the costs for procuring re-usable
formwork. It is also the most flexible type of formwork, so
even where other systems are in use, complicated sections
may use it.
2. Engineered Formwork systems. This formwork is built
out of prefabricated modules with a metal frame (usually
steel or aluminum) and covered on the application (concrete)
side with material having the wanted surface structure
(steel, aluminum, timber, etc.). The two major advantages of
formwork systems, compared to traditional timber formwork,
are speed of construction (modular systems pin, clip, or
screw together quickly) and lower life-cycle costs (barring
major force, the frame is almost indestructible, while the
covering if made of wood; may have to be replaced after a
few - or a few dozen - uses, but if the covering is made
with steel or aluminum the form can achieve up to two
thousand uses depending on care and the applications).
3. Re-usable plastic formwork. These interlocking and
modular systems are used to build widely variable, but
relatively simple, concrete structures. The panels are
lightweight and very robust. They are especially suited for
low-cost, mass housing schemes moladi.

Stay-In-Place formwork systems. This formwork is assembled
on site, usually out of prefabricated insulating concrete
forms. The formwork stays in place (or is simply covered
with earth in case of buried structures) after the concrete
has cured, and may provide thermal and acoustic insulation,
space to run utilities within, or backing for finishes.

Stay-In-Place structural formwork systems. This formwork is
assembled on site, usually out of prefabricated
fiber-reinforced plastic forms. These are in the shape of
hollow tubes, and are usually used for columns and piers.
The formwork stays in place after the concrete has cured and
acts as axial and shear reinforcement, as well as serving to
confine the concrete and prevent against environmental
effects, such as corrosion and freeze-thaw cycles.