What is formwork?
Formworks are an important component in the building industry and may be defined as a temporary or permanent shape into which concrete is poured and hardened.
Formworks are built of wood or steel, with the surface in touch with the concrete chosen to provide the desired finish. The formworks and related false work must be strong enough to hold the weight of wet concrete without substantial deformation.
Formwork comes in a variety of forms in the building industry, including wooden forms, steel forms, aluminum forms, plywood forms, fabric forms, and plastic forms.
In most cases, the formwork is removed once the concrete has reached a suitable strength. However, in certain cases, it may be kept in place (permanent formwork).
For concrete formwork, the most commonly used materials are timber and steel. However, a variety of other materials are used, primarily for specialized applications.
Since the modernization of technology, the construction industry has expanded significantly and rapidly. The use of software in the creation of large-scale building plans and designs has increased construction efficiency, safety, and speed while also significantly reducing costs.
Additionally, the construction materials used today are much more durable and long-lasting than those used even a short time ago, allowing us to build structures that are safer and more useful.
Different Formwork Materials
Formwork is categorized mostly based on the materials used. The following are the many types of formwork materials:
1. Aluminum Formwork
Formwork for pre-fabricated structures is frequently made of aluminum. Due to its robustness and light weight, it is becoming more and more popular. There are fewer connections and support needed.
- It is easy to assemble and disassemble.
- Due to its modest weight, it can be moved around easily.
- It can be reused multiple times.
- Structures’ walls and slabs can be cast simultaneously.
- Aluminum formworks allow for the construction of monolithic, crack-free structures.
- The lighter components could deflect when the load reaches its maximum level.
2. Plywood Formwork
One method of re-molding timber is the use of plywood formwork. Resin-bonded plywood sheets are fastened to wooden frames to create panels in the desired sizes.
It is sturdy, flexible, and simple to use. Compared to other materials, its lifespan is too short.
- Plywood may be simply cut to the desired size.
- Create a smooth finish on the surface.
- It is lightweight and strong.
- Large plywood sheets are readily available, allowing for faster and easier construction.
- It is more expensive than timber.
- Thin plywood sheets cannot support the weight of concrete if the necessary thickness is not given.
3. Timber Formwork
Among all the other forms of formwork, timber forms are the most common. Timber shapes have been widely employed in construction since antiquity. Timber formworks is the most traditional type of formwork used in building.
Timber formwork is the most commonly utilized type of formwork in construction. It provides on-site manufacture of the necessary form and size. It is simple to utilize in any building, although it may take time for huge projects. The longevity of timber formworks is limited. Timber shuttering is inexpensive and simple to install. It may be cut and combined to create any form or size. The following requirements should be met by timber shuttering:
- Termite infestation-free
- Simple to Apply
- Timber shuttering can be shaped, sized, and heightened to any desired shape, size, or height.
- It has been shown to be cost-effective for small projects.
- It may make use of locally available wood.
- Timber is lighter in weight than steel or aluminum shuttering.
- Unsuitable for long-term use
- Wet concrete will absorb moisture from dry timber, which might damage the finished concrete.
4. Steel Formwork
Steel formworks are becoming more popular because of their strength, durability, and long-term usage. Steel formwork is expensive for small jobs but may be utilized for a wide range of tasks. Steel shuttering provides a smoother surface finish to concrete than timber formworks. It is suitable for round or curving buildings such as tanks, columns, chimneys, sewers, tunnels, and retaining walls.
- Steel is robust, long-lasting, and durable.
- It provides a smooth finish to the member’s surface.
- It is entirely waterproof or moisture-proof and reduces honeycombing.
- It may be reused up to 100 times.
- Steel formworks are easier to install and remove.
- Strong and able to lift heavy loads
- Restricted size or shape
- A very smooth surface will be produced, which may cause problems with the finishing procedure.
5. Plastic Formwork
Plastic formworks are lightweight, interlocking, and have a greater than 100-use lifespan. It can be used for regular concrete construction. This kind of formwork is currently becoming common for huge home developments and comparable designs.
- Because plastic forms are lightweight, handling costs are lower.
- The substantial concrete part may benefit from its use.
- It may be reused several times with proper installation and use, which makes it very cost-effective.
- It is an expensive material.
- It does not require much load when compared to others.
In the building industry, fabric formwork is the most recent technology. Fabric is increasingly often used as formwork for architectural reasons since it can be molded into any necessary forms.
- When compared to other formwork materials, it weighs significantly less.
- It is cost-effective.
- Fabric formworks allow for the construction of any complex shape.
- It’s water-resistant.
- Has no effect on the properties of the concrete.
- When the concrete has hardened, it is simple to remove.
Importance of Formwork In Construction
- Formwork is without a doubt necessary for every structure; its major benefit is that it cannot be substituted by any other technique.
- By using formwork, a concrete building may be built fast and most affordably.
- A formwork provides appropriate access and working platforms throughout all phases of construction, significantly improving worker safety.
- Formworks helps to reduce project timelines and costs by shortening the floor-to-floor construction cycle time, which means that more projects may meet their budgetary requirements.
- Formworks enables construction managers to provide precise, on-time shuttering and de-shuttering of formwork resources, which enhances the efficiency of the project and the use of resources.
- Formworks are primarily connected to concrete. It aids in creating a smooth, polished concrete surface.
- It provides solutions for all overlay loads, resulting in extremely safe and useful constructions with high structural safety.
Condition for Quality Formwork
- It should be strong enough to withstand all forms of dead and live loads.
- To maintain its shape, it should be rigidly built and properly propped and braced both horizontally and vertically.
- To prevent cement grout from leaking, formwork joints must be tight.
- Formworks construction should allow for the removal of various pieces in the required sequences without causing damage to the concrete.
- The formwork material should be inexpensive, easily accessible, and reusable.
- The formwork should be precisely aligned with the desired line, and the levels should be flat.
- It should be as light as possible.
- The formwork’s material shouldn’t wrap or distort when exposed to the elements.
- It should have a solid foundation.
Aside from its own weight, formwork is subjected to the following loads:
- Live load due to labor, and so on.
- The dead weight of wet concrete
- The hydrostatic pressure of fluid concrete acts on the forms vertical or inclined faces.
- The effect of concrete pouring
- Vibrational load caused by the vibrator while working
- Moving equipment causes erection stresses.
Formwork Removal Procedure
The following are the orderly procedures and ways to remove formwork:
- Since they do not support any weight but just serve to hold the concrete in place, shuttering that forms the vertical faces of walls, beams, and column sides should be removed first.
- Next, the shuttering that forms the soffits of slabs should be removed.
- In the end, it is best to remove shuttering that is made of beams, girders, or other heavily loaded shuttering.
- When removing, make sure there is no stress or vibration, since this might harm the reinforced concrete.
- Before removing the soffit and struts, the concrete surface should be determined as needed to ensure that the concrete is strong and hardened.