Introduction of Formwork

• Formwork is a mould or open box, like container into which fresh concrete is poured and compacted.
• When the concrete is set, the formwork is removed and a solid mass is produced in the shape of the inner face of the formwork.
• It should be capable of carrying all imposed dead and live loads apart from its own weight.

Requirement of a good formwork

• It should be strong enough to withstand all types of dead and live loads.
• The joints in the formwork should be tight against leakage of cement grout.
• Materials should be cheap and reusable.
• Light in weight, so that easy to transfer.
• The joints in the forwork should be tight against leakage of cement grout.
• Swelling and shrinkage should be minimum.
• It should be practically water proof, so that it should not absorb water from concrete.
• Deflection should be minimum.
• The material of formwork should not warp or get distorted when exposed to the elements.

Categories of Formwork

1. Conventional
2. Modern-Day formwork
3. Engineered/Pre-Fabricated Formwork

Major Objectives consdiered in formwork

• Quality: Forms must be designed and built with sufficient stiffness and accuracy so that the size, shape, position, and finish of the cast concrete and amintained.
• Safety: Forms must be built sufficient strength and factor of safety so that they have the capable of all supporting loads.
• Economy: Forms must be built efficiently, minimizing time and cost.

Types of Formwork Materials

• Timber
• Steel
• Plastic
• Aluminium

Advantage of Timber formwork

• Easy handling because it is light weight.
• Easy to disassemble.
• Damaged parts can be replaced with new one.
• Very flexible.
• Easy to produce.
• Easily available.

Advantages of steel formwork

• It can be used for a no. of times.
• It is non absorbent.
• Smooth finish surface obtained.
• No shrinkage of formwork occurs.
• Easy to use.
• Its volume is less.
• Its strength is more.

Advantages of Plastic formwork

• Light weight
• Reusable
• Che,ical resistant
• Can be easily cut and nail by using wood working.
• Damages on the formwork can be easily removed.
• Very useful for complex shaped and special features.

Advantages of Aluminium formwork

• Quickly and accurately assembled.
• Light weight component provides low pressure on the lower part of the buildings.
• Faster construction cycles.
• High quality finishes.
• Can be easily recycled.
• Safe work platforms.
• High salvage cost.

Safety Precaution

• Material used for the construction of formwork must fulfill the specification.
• Formwork is fixed firmly and properly.
• Cosntruction area must be protected to prevent vandalism of formwork.
• Warning sign must be put up at the area where the formwork is fixed to prevent entrance of people that may damage the formwork.
• The formwork must be inspected before the concrete is poured.