What Is Shutteting?
Shuttering is used as a temporary mould into which concrete is poured to obtain the desired structural shape on the construction site. Traditional shuttering is fabricated using timber, but it can also be constructed from steel, glass fibre reinforced plastics, and other materials.
In the infrastructure & Construction industry shuttering work is similar to a mould to cast concrete members in different shapes and sizes using different types of materials such as timber, steel, aluminum, plastic, etc. shuttering is a synonym term used for form work.
it must have adequate strength to carry the dead load and live load coming on it during casting operation of concrete and after that till concrete gets hard and gain some percentage of desire strength.
Shuttering in construction plays a fundamental role. It must have enough strength to bear all the loads present during operations and then must hold its shape while the concrete hardens.
It can be used as temporary or permanent moulds, which hold the poured concrete in shape until it hardens and achieves enough strength to support itself.
Shuttering is used as a mould for a structure and its ancillary Construction. Concrete is placed in the mould only to harden and gain adequate strength later.
Execution of Shuttering work takes time, and it forms 23 to 25% expenditure on the total cost of the structure or building and probably even more. But, these are short forms of structures that are essential to support concrete until it reaches an adequate level of strength.
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The Shuttering by the name itself “The Mould” which means it is the casing into which material, usually concrete, is poured to obtain the desired structural shape.
Requirements of Good Shuttering:
The followings are general performance features to meet the needs of concrete Construction:
- It should be strong enough to resist all types of dead loads and live loads.
- It should retain its shape and size with adequate props and braces.
- The joints of Shuttering must be tight against leakage and should be of cement grout.
- it should be rigidly constructed and effectively propped and braced on both sides horizontally and vertically, to retain its shape.
- It should be made from reusable and recyclable material.
- If Shuttering is removable, the process must not damage the concrete.
- The material of the Shuttering should be cheap and readily available.
- The material of the Shuttering should be as light as possible.
- It should be set accurately to the desired line, and levels should have a plane surface.
- The Shuttering material should not warp or distort when exposed to the elements.
- Construction of Shuttering should permit the removal of various parts on desired sequences without damage to the concrete.
- It should rest on a firm base.
Types of Shuttering Based on Materials
Following are types of shuttering materials used on construction site
- Timber Form Work
- Plywood Shuttering
- Steel or Metallic Shuttering
- Aluminum Shuttering
- Plastic Shuttering
- Coffer Shuttering
The following formwork for beams columns and slabs
1. Timber Form work
Timber shuttering was one of the first and still most used types of formwork in the construction industry. It is normally assembled on-site.
However, before using timber formwork, its condition must be checked carefully, making sure it is free of termites. Timber Shuttering also has two limitations that must be considered while using it is, it has a short life span and is time-consuming in large projects.
While using timber shuttering, it should be cut into pieces that are large enough to be reused. In general timber, shuttering is preferred when labour costs are minimal, or when multiple concrete sections require flexible form work.
Timber shuttering has following advantages
- Easy to produce and remove
- Economical in small projects
- Workable, allowing any size and height
- Allows the use of local timber
- Lightweight, especially when compared with metallic formwork etc.
2. Plywood Shuttering
Plywood shuttering is an unnatural manufactured wooden sheet available in different thicknesses and sizes used in form work for the concrete member.
It is strong enough, durable, and lightweight. Plywood is one of the most used materials for sheathing, decking, and linings in shuttering. Plywood shuttering has similar properties as timber shuttering including strength, durability, and is lightweight.
The cost of plywood shuttering compares favorably with that of timber shuttering, and it may even prove cheaper under the following considerations:
- It is possible to have a smooth finish in which case surface finishing is there.
- The number of reuses is more as compared with timber shuttering. For estimation purposes, the number of reuses can be taken as 20 to 25.
- In shuttering types, It is possible to more saving on the labor cost of fixing and dismantling.
3. Steel or Metallic Shuttering
Steel shuttering includes panels fabricated out of thin steel plates fixed along the edges by small steel angles. The panel units can be held together using suitable clamps or bolts and nuts. This type of shuttering mostly used in bridge construction work.
Steel shuttering is now becoming popular due to its long lifetime reuses. Steel shuttering could be costly but can be used for a large number of projects and Structures. Steel shuttering offers very smooth and leveled finishes to the concrete surface. It is best suited for circular or curved structures such as tanks, columns, chimneys, sewers, tunnel and retaining walls.
Advantages of steel shuttering with considering timber shuttering
- It gives a very smooth & leveled finish to the surface of the member.
- Steel shuttering is efficient, durable & has a long-lasting life.
- It is waterproof and minimizes the honeycombing effect.
- It can be used more than 100 times.
- Steel shuttering does not absorb moisture from the concrete surface.
- It can be installed & dismantled easily.
4. Aluminum Shuttering
Aluminium shuttering are very similar to steel shuttering. The main difference is that aluminium has a lower density than steel, which makes formwork lighter.
Aluminium also has a lower strength than steel, and these criteria must be considered before using it in the construction project.
Aluminium shuttering is economical if large numbers of repeating usage types of projects are made in Construction. The main disadvantage is that no alteration is possible once the shuttering is constructed.
5. Plastic Shuttering
Plastic shuttering is executed by interlocking panels or modular systems, made of lightweight and robust plastic. It works best in small projects consisting of repetitive tasks, such as low-cost housing estates. It can be used for simple concrete structures.
Plastic shuttering is light in weight and can be cleaned with water while being suitable for large sections and multiple reuses. Its main drawback is having less flexibility than timber because many components are prefabricated. These types of shuttering are becoming favorable for similar shapes and massive housing schemes.
Advantages of Plastic shuttering
- Plastic shuttering are one of lightweight shuttering; hence it requires less handling and dismantling cost.
- It can be used for a large section.
- If carefully transported and used, multiple reuses are possible; making is highly economical.
6. Coffer Shuttering
Coffer shuttering is a stay-in-place formwork system. It is consists of two filtering grids which are reinforced by vertical & horizontal stiffeners and linked by articulated connectors which can be folded to transport on-site.
Coffer shuttering remains in place after the concrete is poured and acts as reinforcement. Coffer is transported to the site prefabricated from the factory. These shutters can be used for any type of structure like a house, multistory buildings, etc.
Types of Shuttering Based on Structural Components
All types of shuttering are designed according to the structure or unit they support, and the corresponding construction plans specify the materials and required thickness. It is essential to note that formwork construction takes more time.
Following are shuttering types based on structural components,
- Wall Shuttering
- Beam Shuttering
- Foundation Shuttering
- Column Shuttering
- Permanent Insulated Shuttering
1. Wall Shuttering
Wall Shuttering used for concreting of shear or RCC wall in dams, wing wall, basement RCC walls, etc. Wall shuttering made up of vertically arranged upright timbers to which plywood sheeting boards are nailed at the inner side. The upright timbers are diagonally braced with the help of boards at the sides.
2. Beam Shuttering
The beam is the most crucial structural member in RCC framed building. Beam shuttering has prefabricated shuttering includes sheeting bottom and side sheeting panels.
The individual parts of the shuttering are manufactured based on the beam size. In the process of prefabrication of sheeting parts, table fabrication must be manufactured on-site where pouring of concrete to be done. These types of formwork specially made for beam construction work.
3. Foundation Shuttering
Foundation shuttering is designed according to foundation type. The design of formwork for a foundation depends on foundation type like strip footing, combined footing, raft.
Mainly there is a difference in the design for private foundations and formwork for strip foundations. The design of shuttering is estimated by the size, mainly by the height of the foundation.
4. Column Shuttering
Arrangement of formwork for the column may change based on column outlines like rectangular, circular and hexagonal or any other shape. The sheeting of column shuttering is constructed according to the column dimension. The panels are accommodating in a foot rim, anchored in soil with the help of bolts.
5. Permanent Insulated Shuttering
These are one of the most advanced types of Shuttering systems, offering permanent insulation. It may also consist of thermal, fire-resistance, acoustic, and rodent-resistance properties.
Insulating concrete forms are the most usual type of permanent insulated Shuttering, where concrete structures are insulated with polystyrene boards that stay in place after the concrete has cured.
Permanent insulated Shuttering offers energy efficiency and sustainability, contributing to a lower environmental impact from the building sector.
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