Formwork for Foundation
Theory
Formwork for foundations is a critical aspect of concrete construction, providing the necessary shape and support for concrete as it cures. The formwork acts as a temporary structure, designed to hold the concrete in place until it achieves sufficient strength to support itself. Proper formwork design ensures that the foundation will have the correct dimensions and surface finish, while also withstanding the pressures exerted by the fresh concrete. The effectiveness of the formwork directly impacts the quality and durability of the foundation, making it a key factor in the overall success of the construction process. Since footings are below ground and typically concealed, the appearance of the concrete surfaces is less critical for footing formwork. Therefore, cost-effective formwork materials are often preferred. However, to ensure straight and smooth concrete surfaces, it's essential to choose materials that are of good quality and maintain their shape. Reinforced cement concrete construction uses various foundation types, including wall foundations, individual column footings, stepped or tapered footings, offset footings, sloped footings, monolithic footings, round footings, and rafts, with conventional formwork primarily made of timber boards, planks, or plywood.
In foundation formwork, various components work together to ensure the structure’s stability and precision. These elements include floor form corners, floor forms, clips, wallers, and CT props, among others.
Foundation Formwork Components:
- Floor Form Corner: This is Positioned at the corners of the formwork. These components maintain the form’s shape and stability.
- Floor Form Panels: These are the primary panels that create the sides of the formwork.
- Floor Form Clips: These clips securely hold the floor form panels in place.
- Waler Clamps: Used to attach waller pipes to the floor form, ensuring they stay connected.
- Waler pipes: Horizontal supports added to the formwork for extra stability.
- Steel Waler: Steel beams that provide additional structural support to the formwork.
- CT Prop (Double Nut): Adjustable vertical props that support the formwork and allow for height adjustments.
- Head and Foot Adapters: Connectors that attach the CT props to the formwork and the ground, securing the entire structure.
A brief explanation of each step of the procedure of the experiment is given below.
- Marking of the area for the foundation: This step involves the marking of the land surface dimensions of the formwork by drawing lines in rectangularly and diagonally ensuring the accuracy.
- Bringing of the floor form corner, floor form panel, and waler clip: These components are crucial for constructing the basic framework of the formwork.
- Connecting of the floor form panels with the floor form corner using waller clips: In this step the waler clips are utilized to connect the three floor form panels to the floor form corners and that ensures the corners of the formwork are secure and stable.
- Attachment of the waler pipes by using the pipe waler clamps: Two waler pipes to be attached to the setup at the back surface of the floor form panels horizontally by using the pipe waler clamps to provide the horizontal support and maintain the vertical stability of the form floor panels.
- Attachment of the steel walers to the waler pipes by using the steel waler connectors: Three steel walers to be connected vertically to the waler pipes by using the steel waler connectors, anchor plates, and wing nuts in this step. These attachments add the strength and rigidity to the formwork and ensure that it can withstand the pressure exerted from the fresh concrete.
- Attachment of the CT props to the steel walers by using the head and foot adapters: This step concludes the construction of one side of the formwork for a block foundation. These CT props provide an additional vertical support to ensure that the formwork can withstand the weight of the concrete.
- Repeating of the steps 2 to 6 other three sides to complete a consistent and stable formwork for a block foundation.
A well-constructed formwork considers various factors, such as the foundation type, the loads it must bear, and the environmental conditions. Effective formwork construction depends upon efficient communication and coordination among the construction team, comprising engineers, contractors, and laborers.