Introduction
Shuttering or formwork are terms alternatively used in the architectural and construction industry and honestly, we have never given much thought about it, but since you are curious and here, you will know everything you need! Let’s address everyone’s biggest doubt and clear the air.
Formwork often is a temporary ‘mould’ in which concrete can be poured. Formwork is the term used to describe the forming process. It is shaped to form the desired framework to cast the wet concrete mix and is left to set till it retains its shape. Vertical formwork, used for columns, retaining walls and footings, is known as shuttering. Shuttering is a part of formwork. Whereas, formwork for slabs, floors and beams is called centring.
This is required for structural parts that are precast and the ones which are made in situ. Traditionally it was fabricated using timber, but now it’s constructed in steel, glass fibre, reinforced plastics and other materials.
All shuttering and formwork require external support given by stabilizers, poles and other materials, this is called bracing and is left in place until the concrete dries. Temporary members such as props, jacks, cup lock systems etc used to support centring or shuttering are called staging. The act of removing formwork and shuttering is called stripping.
Stripped formwork can be reused in most cases, other times it remains in place for good.
Now that we have cleared your basics, we will move on to knowing the types of shuttering and formwork.
Types of formwork:
- Timber Shuttering is the traditional and popular choice as it can be accommodated according to the requirements of the projects. It is used in combination with modular steel bracings for shuttering.
- Plywood is the cheaper alternative to timber and can be successfully recycled or reused. It must be noted that the plywood used is water-resistant.
- Steel shuttering consists of steel plates stiffened along the edges using small steel angles. These can easily be fabricated in large numbers as per the project requirements and are used for circular and curved structures, especially.
- Plastic shuttering is generally used for quick pour work for repetitive, small-scale structures.
What a good formwork needs:
Formwork is an integral part of the building construction and determines the overall execution of the architectural project and must begin with a firm base. The formwork is designed and constructed to the required dimensions with tolerance for ±10mm. The shuttering must have reasonably accurate lines and levels and be carefully removed to not damage the concrete.
The entire formwork assembly must retain its size and shapes upheld with props and braces to prevent distortion and warping when exposed to elements.
It also must be leak proof while being resistant to water. The smallest contribution made by the construction industry would be to use reusable and recyclable materials.
Types of shuttering according to structural components :
To construct all building components shuttering or centering is required.
1.Shuttering for walls :
Concrete walls are used for constructing shear walls in buildings, RCC walls for dams, retaining walls, basement walls among other places. Wall shuttering is arranged vertically upright using timber planks with plywood nailed on the inside. These are diagonally braced with the help of wooden boards or steel members at the sides.
2. Shuttering for beams :
Beam is the structural member that is primarily responsible for load distribution making it a crucial member to structure correctly. To center a beam, prefabricated sheets of shuttering are used which sheet the bottom and the side known as sheeting bottom and side sheeting panels. The components of the formwork are manufactured to size.
3. Shuttering for columns :
Columns are designed in many shapes and forms as per the requirements of the projects. The most commonly used shapes are rectangular, circular and hexagonal.
Since the requirements of individual projects the column sheeting is constructed to dimension accommodating in a foot rim, anchored into the soil with bolts.
4. Shuttering for foundation :
The type of foundation, strip footing, combined footing or raft, and the size and height of the foundation dictates the design of the formwork.
Mivan formwork :
The most advanced type of formwork in the market currently is the Mivan formwork. It is a system made of strong, durable, simple, ready to install and adaptable used in construction of mass housing projects.
It is primarily used where construction is to be done in concrete completely. Mivan Formwork consists of components for each structural element, that is, wall, beam, decks or slab and other components to cover the edges. Since one full floor of a structure can be casted together, the construction is quick.
Scaffolding :
A part of the formwork saga is the scaffolding. Scaffolding are stilts and temporary platforms put up around the structure for construction workers and materials to access parts of the building.
A stable and strong support made of wood or steel is made to ensure safety of the workers while the structure is being constructed or maintained. It is installed before the construction or maintenance work commences.
Lets understand what goes in a scaffolding.
Components of a scaffolding:
- Standards or uprights are perpendicular tubes that distribute the load to the ground, just like the column in a framed structure. They lean on a square base plate to scatter the weight.
- Ledgers are flat tubes that span between the standards.
- Transoms or putlong are transverse stay at right angles to the ledgers. The load bearing transoms are placed near the standards and give support to the boards.
- Braces are inclined members placed diagonally to the standards to give additional support.
- Planks and boardings are flat horizontal members that are supported by the putlogs and provide a working platform for men and material. Rails or guardboard safeguard against men and material from topping over the planks.
- Volts are to bind the various parts of the scaffolding.
Types of Scaffolding:
- Single Scaffolding also known as bricklayer’s scaffolding, like the name suggests is used for brick masonry. It consists of the basic components of a scaffolding placed at intervals of roughly 1.2m-1.5m, where putlogs are supported with holes in the walls.
- Scaffolding used for stone masonry is called a Mason’s scaffolding or Double scaffolding. A stone building renders it difficult to make holes to support the putlogs and so a double layer of scaffolding is put up.
The first layer stands approximately 20-30cm away from the wall and the next one is a meter away from the first row. Cross bracings make the frame strong and sturdy and hence, it is also known as the independent scaffolding.
- Cantilever scaffolding used under conditions when that ground cannot support the stands, it needs to be free from traffic and/or the upper part of the wall is under construction. The two methods to do this are with single frame or double frame type of scaffolding.
For single frame scaffolding in cantilevers, the standards are propped on a series of needles that are taken out through holes in the walls whereas in double frame or independent type, the needles are strutted inside the floors through openings.
- Suspended scaffolding, as the name suggests, is suspended from the roofs with the help of wires, ropes or chains for the purpose of painting, repairing, cleaning and others. The height of the platforma can be adjusted using said ropes and chains.
We hope this article provides you the much-needed clarity on formwork, shuttering and scaffolding. Watch this space for some more relevant information on topics related to architecture, interior design and materials.
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