FORMWORK (SHUTTERING) FOR CONCRETE CONSTRUCTION

A Formwork is a temporary structure used as a mold for the original structure. There are different materials available to construct the formwork. Formwork Material is selected depending upon many factors like cost, requirement, type of structure etc.

Formwork (Shuttering) is temporary support as a mould for fresh concrete, in which concrete is poured and cast in the desired shape and gain initial strength, hardened and matured. Formwork is used in different shapes and sizes according to our construction elements in the form of PCC, RCC works in Building, Bridge, Tunnel Lining, Hydropower Dam, Irrigation Headwork, Sanitary Pipeline work, etc.

Requirement for Good formwork (Shuttering):-

Good formwork should satisfy the followings requirements:

• The material of the formwork should be cheap and it should be suitable for reuse several times.
• The form should be practically waterproof so that it does not leak and absorb water from concrete.  Also, its shrinkage and swelling should be minimal.
• It should easily carry the load of concrete and live load of pouring, vibration, compaction, and curing.
• It should have enough stiffness and rigidity so that deflection is minimum.
• As soon as possible it should be light in weight, smooth and should be easily stoppable.
• All the joints in formwork should be leakproof.
• The formwork should rest on non-movable supports.

Different formwork materials:-

1. Timber
2. Plywood
3. Steel
4. Aluminum
5. Plastics
6. Fabric

1. Timber Formwork:- Timber formwork is the most common type of formwork among all others. Timber forms are extensively used in construction since the ancient period. Timber formwork is the oldest type of form used in construction.
2. Plywood formwork:- Plywood formwork is one of re-molded timber resin-bonded plywood sheets are attached to timber frames to make up panels of the required sizes. It is strong, flexible, and easy to handle. Its life is too short compared to other materials.
3. Steel formwork: – It is one become more popular due to its strength, durability, and repetitive reuse for a long period. Steel formwork is costly for small work but can be used for a large number of projects. Steel shuttering offers a smooth surface finish to concrete compared to timber formwork. It can be used for circular or curved structures such as tanks, columns, chimneys, sewers, tunnels, and retaining walls.
4. Aluminum Formwork:- As we know the density of aluminum is less than compared to steel and that makes it light-weighted than steel. This is the main advantage when compared to steel. Aluminum formwork is almost the same as the formwork made from steel. Shuttering down with aluminum form is proven economical if large numbers of repeating usage are made in construction. Its major drawback is that no alteration is possible once the formwork is constructed.
5. Plastic Formwork:-Plastic formworks are lightly weighted, interlocking systems and can be used more than 100 times. It can be used for normal concrete construction. This type of formwork is now becoming popular for similar shapes and large housing schemes.
6. Fabric Formwork:-With the advancement and new technology trends in building planning and designing, the construction of complex-shaped structural members is increased. To satisfy this need the fabric formwork is introduced which made the flexibility of this material makes it possible to produce concrete in any shape. The flexibility of fabric formwork makes it possible to produce concrete members of any shape.