What Is Formwork | Use of Materials in Formwork | Types of Formwork | Requirements Good of Formwork | Advantages & Disadvantages

What Is Formwork?

Formwork is the mould used during the building to give the desired structural form by pressing concrete into the mould. In a single term, formwork is a mould that cast concrete in various shapes and sizes. There are a few other different forms of formwork commercially available.

Shuttering is synonymous with the word Formwork. In certain nations, users are using the term shuttering rather than formwork.

Formwork (Shuttering) has become temporary assistance as a mould for concrete mixture wherein concrete is placed to formed in the required shapes as well as obtains initial strength, strengthened and developed.

Formwork is often used in various shapes and sizes depending on our design materials in the form of PCC, RCC operates in Building, Road, Corridor Lining, Hydroelectric power Dam, Agriculture Headwork, Sewage Pipeline Works, etc.

The expense of formwork is estimated to have been 20 to 25 percent of the cost of construction work, which could be greater than that for bridges. To attempt to lessen the expense of formwork, it is important to design and manage economical forms of formwork.

Designers will also have to extract the shape until the concrete has achieved the required power. The method of separating the formwork is often called stripping.

Within a week of stripping the form, the materials are separated it can be used in some building projects or several other sections of the job. The reproducible type of formwork materials is recognized as the form of a panel.

Also, Read: Deshuttering Time | When to Remove Concrete Forms | Concrete Formwork Removal Time | Earliest Time to Remove Concrete Forms | When To Strip Concrete Forms

Use of Materials in Formwork:

Forms are the following types on the basis of materials:

• Form of wood.
• Type of plywood.
• Form of steel.
• The combined form of wood-steel.
• Strengthened concrete form.
• Plain concrete shape.

Above this, timber is typically used as formwork and is sometimes inexpensive. Although the risk of warping, expanding, and diminishing the wood is a downside of the timber.

It may reduce such flaws by adding protective coatings to the shutter. Such impermeable coating often allows stripping as well as avoids adhesion to the concrete.

A steel shutter is then used to obtain the correct form and purpose of the aesthetics.

Also, Read: Mivan Shuttering | Merit & Demerit Mivan Technology | Mivan Formwork Assembly Process

Types of Formwork:

Types of Formwork are as follows.

• Timber Formwork.
• Plywood Formwork.
• Steel Formwork.
• Aluminum Forwork.

#1. Timber Formwork-

Timber Formwork should comply with the following requirements:

• It ought to be well seasoned
• It ought to be light in weight
• Timber must be easy to work with nails without splitting.
• It’s supposed to free from loose loops.

The timber being used formwork must have a smooth and sometimes even surface from all sides, that also comes in direct contact with concrete.

Timber formwork is being used in a small amount of concrete work.

Advantages of Timber Formwork:

• Timber can even make it perfect in any size you want.
• Timber is extremely lightweight so that it can be managed rapidly.
• Timber is indeed a good thermal resistance, which helps prevent concrete harm in colder areas.
• The fabrication process for that kind of sort of formwork is easily understandable, so it does not involve skilled labor.

Disadvantages of Timber Formwork:

• Dry timber contains moisture from concrete, which also reduces the workability of the material.
• Timber formwork should only be modified 5 to 6 times.
• Timber with such a higher moisture content (<= 20%), wet concrete would then reduce as well as Cement slurry would then spill. 

Also, Read: Difference Between Formwork, Shuttering, Centering, Staging & Scaffolding

#2. Plywood Formwork-

Formwork of Plywood for structural concrete is often waterproof Boiling level plywood, seems to be a preservative-treated material, and has been particularly suited to be used in shuttering and formwork.

Plywood formwork is quite economical, and can also be used repeatedly, based on the precautions given all through erection as well as demolishing.

Formwork of Plywood for structural concrete is often waterproof Boiling level plywood, seems to be a preservative-treated material, and has been particularly suited to be used in shuttering and formwork.

Plywood formwork is quite economical, and can also be used repeatedly, based on the precautions given all through erection as well as demolishing.

The major benefit that the use of plywood shuttering is that it is long-lasting under intermediate weathering situations, Plywood seems to have a solid surface and also has sufficient strong enough to withstand the loading of concrete as well as the needs to produce by the spilling of concrete as well as sound waves.

Advantages of Plywood Formwork:

• Plywood can be conveniently cut to the appropriate scale.
• Plywood is sturdy, robust, and lightweight.
• Plywood offers a flat concrete surface finish.
• Plywood makes the formwork smoother and simpler.

Compared to Timber Formwork plywood, there is more repetition.

Also, Read: What Is Formwork Failure | Causes of Formwork Failure

#3. Steel Formwork-

Steel formwork consists of a sheet consisting of thin steel plates. Steel Formwork is common nowadays because it gives you a long life cycle and gives you better replication.

The steel panel units may be mounted together using the necessary clamps, nuts, and bolts. Steel Panels can be manufactured in either modular form or scale.

Often this style of formwork is used for circular and curved construction.

Advantages of Seel Formwork:

• Steel panels are sturdy, robust, and also have a longer life cycle.
• Steel panels can also be quickly assembled and removed at high speeds.
• It is cost-effective if there is a significant volume of development going on.
• Glass panels do not retain Concrete water or moisture.
• This style of formwork does not shrink or warp.
• The consistency of the concrete surface of the steel formworks is smooth and does not need further treatment.

Disadvantages of Seel Formwork:

• It’s very pricey compared to Plywood.
• The steel sheet is very high in weight, it requires moving equipment to lift the panel.
• It’s limited to scale and form.

Also, Read: Concrete Release Agent | Functions of Releasing Agents | Types of Concrete Release Agent | Advantages of Release Agent | Concrete Form Release Oil

#4. Aluminum Forwork-

Aluminum formwork is identical to stainless steel formwork. This form of formwork becomes lighter than that of the steel formwork, owing to the low strength of the aluminum is lighter than the steel.

This form of formwork is inexpensive if a sufficient number of cycles are rendered in Building.

Advantages of Aluminum Formwork:

• Aluminum Formwork improves the pace of manufacturing and reduces time and effort.
• It provides a cleaner and improved surface finish.
• Aluminum formwork could be re-used up to 250 cycles.
• It’s also cost-effective if a significant number of symmetrical buildings have to be constructed.

Disadvantages of Aluminum Formwork:

• The original cost is higher due to the more costly aluminum formwork.
• This type of formwork is cost-effective when used in a symmetrical design of construction.
• It takes time to set up, initially.
• Professional tasks are needed for alignment and maintenance purposes for this style of formwork.
• Holes created by a wall tie during the formwork should be cracked correctly, otherwise, there will be a leakage problem in the future.

Also, Read: What Is Shoring In Construction | Type of Shoring

Requirements Good of Formwork:

• The material used in the formwork should be inexpensive and ideal for re-use many times.
• The shape should be essentially waterproof so as not to spill and trap water from asphalt. Its shrinkage and swelling should also be minimal.
• A load of concrete and live loads of pouring, vibration, compaction, and curing can be carried quickly.
• It must have enough stiffness as well as stiffness to reduce deflection.
• It should be low in weight as soon as possible, smooth, and easy to avoid.
• All joints in the formwork should be evidence of leakage.

Also, Read: Introduction of Bamboo | Advantages & Disadvantages of Bamboo | Bamboo Uses in Construction | Properties of Bamboo as a Construction Material | Bamboo Architecture

Code Provision for Standard Formwork:

• General Requirements.
• Cleaning and Preparation of Forms.
• Strip Time.
• Procedure for Eliminating the Formwork.
• Camber.
• Tolerance.

#1. General Requirements-

The formwork shall adhere to the orientation, the lines, and the proportions as shown in the drawings and shall be built so as to remain sufficiently stable throughout the placement and compaction of the concrete and shall be sufficiently close to avoid the leakage of liquid from the concrete.

#2. Cleaning and Preparation of Forms-

All waste, in particular chippings, shavings, and sawdust, shall be removed from the inside of the molds until the concrete is put and, thus, the formwork in contact with the concrete shall be washed and thoroughly wetted or handled with an accepted composition.

Bear in mind that the accepted composition should not be influenced by the reinforcement.

#3. Strip Time-

In no case shall the shape be hit before the concrete exceeds an intensity of at least twice the pressure under which the concrete could even be exposed at the time of the attack.

#4. Procedure for Eliminating the Formwork-

At the point of elimination of the formwork, remember that there is still no vibration or movement that will harm the reinforced concrete.

Even before soffit as well as the struts are extracted, the concrete surface shall be monitored, if necessary, to ascertain that the concrete is properly solid and hardened.

Proper care shall be taken to allow for a reduction in the rate of hardening that occurs with all cement in cold water unless it is allowed in the design formulas of the beams.

#5. Camber-

It is usually desirable to provide upward camber shapes to guarantee that the beams do not even have a sag after they have retained their deflection, although this could not be achieved unless suggested by the calculated configuration of the beams.

#6. Tolerance-

Formwork must be designed in such a way that the internal dimensions are well within the acceptable tolerance defined by the designer.

Also, Read: Spandrel Beam Definition | Properties of Spandrel Beam | Advantages & Disadvantages of Spandrel Beam | Uses of Spandrel Beam | Spandrel Beam Design