DEFINE FOAMWORK? Ans: 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.
Posted on: Wed, 10 Dec 2014 14:47:24 +0000
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