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Formwork is the term given to either temporary or permanent molds into which concrete or similar materials are poured. In the context of concrete construction, the falsework supports the shuttering moulds. ==Formwork and concrete form types== Formwork comes in several types: #''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 labour costs are lower than the costs for procuring reusable formwork. It is also the most flexible type of formwork, so even where other systems are in use, complicated sections may use it. #''Engineered Formwork System''. This formwork is built out of prefabricated modules with a metal frame (usually steel or aluminium) 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 aluminium the form can achieve up to two thousand uses depending on care and the applications). #''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. #''Permanent Insulated Formwork''. This formwork is assembled on site, usually out of insulating concrete forms (ICF). The formwork stays in place after the concrete has cured, and may provide advantages in terms of speed, strength, superior thermal and acoustic insulation, space to run utilities within the EPS layer, and integrated furring strip for cladding finishes. #″Coffor″ is a structural stay-in-place formwork system to build constructions in concrete. It is composed of two filtering grids reinforced by vertical stiffeners and linked by articulated connectors that can be folded for transport. A standard panel 1.10 m x 2.70 m (3' 8'' x 9'') weighs 32.7 kg (72 lbs) and can be carried by hand or by any means of machine. After Coffor is placed, concrete is poured between the grids: excess water of concrete is eliminated by gravity and air is also eliminated. Coffor remains in the construction after concrete is poured and acts as reinforcement. Any type of construction can be built with Coffor: individual houses, multi-story buildings including high-rise buildings, industrial, commercial or administrative buildings. Several types of civil works can be done with Coffor. Coffor is delivered completely assembled from the factory. No assembly is necessary on the construction site. #''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. # Flexible formwork. In contrast to the rigid moulds described above, flexible formwork is a system that uses lightweight, high strength sheets of fabric to take advantage of the fluidity of concrete and create highly optimised, architecturally interesting, building forms. Using flexible formwork it is possible to cast optimised structures that use significantly less concrete than an equivalent strength prismatic section,〔Orr, J. J., Darby, A. P., Ibell, T. J., Evernden, M. C. and Otlet, M., 2011. Concrete structures using fabric formwork. The Structural Engineer, 89 (8), pp. 20-26.〕 thereby offering the potential for significant embodied energy savings in new concrete structures. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「formwork」の詳細全文を読む スポンサード リンク
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