Formwork |Components and Materials of The Formwork |Types of Formwork
Today I have a topic of formwork. in this topic, I will explain what is formwork, the importance of formwork components of formwork, the materials of formwork, the Features of Formwork, and the different types of formwork. Formwork| Components and Materials of The Formwork| Types of Formwork. Formwork |Components and Materials of Formwork |Types of Formwork
Formwork |Components and Materials of Formwork |Types of Formwork
Introduction of Formwork
Whenever concrete work is done for example, if roofs or beams are made or columns are made, then temporary support is required to mound the concrete to the desired shape which is called formwork or shuttering. The formwork should be such that the concrete structure may get the surface clean.
Importance of Formwork
Fresh concrete does not have any strength but the characteristic of concrete is that sufficient strength increases with the passage of time. After 4 weeks it has reached sufficient strength and when it is not able to support it, then temporary support (Form Work) is required. Its duration varies in different works. For example, in the case of a beam or slab, the support to the sides needs only 24 hours. The bottom support should be lost after at least 14 days.
Features of Formwork
Form Work should have the following features.
- It should be strong enough to easily bear all kinds of loads of itself and those above it.
- To be made in such a way that it can be easily removed immediately when needed.
- Formwork should be non-absorbent as far as possible.
- The structure should be such that it can be used repeatedly.
- Its surface should be smooth so that the concrete surface becomes smooth.
- Formwork should be cheap in terms of building.
- Formwork should be such that the joints are minimal.
- Form Work should be such that the concrete can be molded properly.
Components of Formwork
Whether the formwork is made of wood or steel, it is made up of different components. The different components of the formwork are as follows
The vertical supports of formwork are called props. These props carry all the weight of the formwork. So they have to be strong.
Pieces of wood or iron are used on the floor level below the props so that the load on the props can be spread over a larger area with props.
A wedge is used between the base plate and its help, the props are tightened. And when the formwork is removed, they are removed first.
In wooden formwork, planks are placed under the concrete structure. They are made according to the size of the concrete structure.
Beams are used in wooden or iron formwork to support planks. They are also called joists.
Horizontal braces are used to strengthen the props and inclined braces are used to support the boards.
The supporting member used to fasten planks to the sides is called a yoke.
The vertical planks of the formwork made for beams are called walling.
Materials of Formwork
The following materials are used keeping in view the quality of concrete work and the required surface finish.
1- Wood Formwork
2- steel Formwork
3- Plastic Formwork
4- Fiber Glass Formwork
Usually, wood is used for formwork. The moisture content of wood used for formwork should not exceed 15 to 20 \%. If the wood is dry, it should be waited before pouring the concrete. Raw wood boards are commonly used for this purpose. Plywood is used for large and sophisticated works. Its surface is smooth and it is available in identical large pieces. Plywood sheets are 1.2 meters (3.5 feet) wide, while standard lengths of 2.4 meters (7 feet), 2.7 meters (8 feet), and 3 meters (10 feet) are available. Chipboard is also used for formwork. But it is a weak material, so more support is needed. Wood formwork can be used 15 to 20 times.
Steel is used in high-quality formwork. The use of steel formwork helps to get concrete of clean surface. Steel formwork uses steel plates of the required size. These plates are supported by steel pipes. Wood is also used for support. Such formwork is called combined formwork of wood and steel. The joints are sealed with an adhesive bandage. Steel formwork can be used 30 to 40 times.
This formwork is also called plastic lining. Plastic formwork is also used to achieve a very high-quality finish. In addition, plastic formwork is used to obtain specific types of design finishes. This formwork is usually used in conjunction with wood or steel formwork. With the help of plastic formwork, decorative designs are made on the roofs. Plastic formwork can be used 5 to 10 times.
Fiber Glass Formwork
This formwork is also called fiber lining. Fiberglass formwork is used in the same way as plastic formwork with wood and iron formwork. Fiberglass is stronger than plastic. we can use these materials 16 to 20timesIt also helps to create beautiful designs on concrete surfaces
Types of Formwork
When choosing formwork for the construction of any building, the nature of the building. The style of construction and the surrounding environment are taken into account. The following are different systems depending on the method used.
1-Traditional Form Work
2-Progressive Form Work
3-Slip Form Work
4-Non-Removable Form Work
Traditional Form Work
This formwork is also called Collapsible Form Work. This type of formwork is used in most types of construction work. It uses wooden or iron boards. Which are held in place by vertical supports. These vertical supports are called studs. Horizontal members are used to supporting them. These are called wallings. Tie bars are used to hold the vertical boards in place. After the concrete is poured into the wall or column and hardened, the formwork is removed and the tie bars are removed.
Progressive Form Work
In this formwork, after completing the concrete work in any of the construction components, the formwork is not separated but the same formwork is used in the next part. After pouring concrete and curing in the next part, the formwork is taken off and used for the next part. This type of formwork can be better used to build a wall with deep cutting. In addition, this formwork is considered better for building a wall with sheet piles. Thus only one side of the concrete wall needs formwork. On the other side, it is supported by soil or sheet piles. In this case, more braces are needed to keep the formwork in place. This method can also be used for a common concrete wall. Using this formwork significantly reduces the time that takes to remove and reapply the formwork.
Slip Form Work
This formwork uses standard formwork components. Using this formwork, the formwork is gradually lifted while building a wall or column. In this way, the construction work continues.. No joint is formed in the wall constructed in this way. This type of formwork is considered better in the construction of multi-story buildings and fireplace etc. With the use of this formwork, the construction work can be continued for 24 hours. For this, material, labor, light, etc. should be provided continuously. In addition, for this, specially trained technical staff is required.
Non-Removable Form Work
Sometimes construction has to be done which makes it very difficult to remove the formwork after construction. In this case, the formwork is allowed to stick with the construction. This formwork is called non-removable formwork. Such a situation often occurs in the construction of the Raft Foundation. In addition, this formwork is also useful in situations where it is necessary to install tiles, etc. in front of the concrete wall to create beauty as it is easy to install tiles on a wooden surface. This system of formwork is used exclusively to make thin concrete walls.