Qualities of a Good Formwork and How It is Constructed

08 September 2022

Formwork in the construction industry pertains to the moulds or open boxes on which fresh concrete is poured and compacted. These things, which are often made of steel, aluminium, wood, and/or prefabricated forms, support the reinforced concrete until it reaches the strength desired by the contractors. Some formworks may be a permanent mould, while others can be temporary that can be later removed through the stripping process.

Qualities of a Good Formwork

While all formworks intend to provide support to reinforced concrete, some of them end up ruining the whole construction project. To ensure that a formwork can carry out its function, it should possess the following qualities.

• Load Resistance: One quality of a quality formwork is it has resistance to both dead and live loads. Since it will be handling the reinforced concrete for a long time, it should be able to handle any load that will be thrown at it. Take note that it should also be as light as possible to prevent structural collapse and other damage.

• Built Up Properly: A good formwork should also be built up firmly and properly. This structure must be braced horizontally and vertically to retain its shape throughout its existence. And if it will be disassembled, its parts must be eliminated in proper sequences to avoid damaging the poured and compacted concrete.

• Tight Joints: Cement grout is composed of cement and water, which provides a layer between or around concrete and structures. Now, leakage of cement grout can be problematic for construction works as its elements may reach areas that must be free from them. Hence, the formwork should possess tight joints to prevent this issue.

• Strong Materials: Of course, the formwork can be considered as good if it has strong materials. The materials used for this structure must not deform or wrap throughout the project to make it functional and safe. They must also be cost-effective and recyclable.

The Construction of Formwork 

When constructing a formwork, contractors would normally carry out propping, centring, shuttering, camber provision, cleaning, and surface treatment.

Propping and centring are essential for the formwork to retain its shape throughout the project. The materials used for centring would often involve steel, timber posts, bullies, or brick pillars. When using a wooden plate, it must have an area of at least 0.1 sqm and should have a thickness of 40 mm. Sole plates and the timber props must then be provided with double wedges to effectively adjust the shuttering before the concreting process is carried out.

Shuttering consequently can be carried out with timber planks or form panel units, which can be created by fixing plywood to timber frames or by welding steel plates to angle framing. The joints of the shuttering must then be tight to prevent leakage of cement grout.

Camber provision in the horizontal members of the concrete structure should then be set to minimise the effect of deflection in a structure. For slabs and beams, their camber should be at least 4 mm per meter span. Ultimately, the formwork must be cleaned first before concreting. Surfaces of timber shuttering that will be in contact with concrete must then be wetted with water. Steel forms exposed to hot weather must also be cooled by water before concreting.

If you need quality formwork for your construction project, you can contact us at Cycon Monero Group.

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