Formwork, also known as shuttering, is a temporary mold or structure used to shape and contain wet concrete until it solidifies. The mold supports the concrete until it’s strong enough to stand on its own and support other loads. Formwork can be used to create concrete into structural shapes like beams, columns, slabs, and shells.
What is Formwork?
Formwork is a temporary structure used in construction to shape and contain concrete during its curing process. It’s essentially a mold that gives concrete its desired shape, whether it’s a simple slab, a complex beam, or an intricate architectural element. Once the concrete has hardened, the formwork is removed, leaving behind the finished structure.
Types of Formwork
- Wooden Formwork: This is the most traditional and widely used type. It’s versatile, easy to work with, and relatively inexpensive. However, it can be time-consuming to assemble and may require additional bracing for larger structures.
- Metal Formwork: Made of steel or aluminum, metal formwork is more durable and reusable than wooden forms. It’s often used for large-scale projects and can be customized to fit specific shapes.
- Plastic Formwork: Lightweight and corrosion-resistant, plastic formwork is suitable for smaller projects or for creating intricate details.
- Composite Formwork: Combining the properties of different materials, composite formwork offers a balance of strength, durability, and reusability.
Key Components of Formwork
- Form Panels: These are the main structural elements that define the shape of the concrete.
- Ties: Used to hold the formwork together and prevent it from spreading during pouring.
- Bracing: Provides additional support to the formwork, especially for large or complex structures.
- Accessories: Includes items like shims, wedges, and leveling devices to ensure accurate placement of the formwork.
Formwork Process
- Planning: The formworks design is based on the architectural drawings and engineering calculations.
- Assembly: The formworks components are assembled on-site, often using temporary supports.
- Reinforcement: Steel reinforcement bars (rebar) are placed within the formwork to provide strength and durability to the concrete.
- Pouring: The concrete is poured into the formworks, ensuring proper compaction and leveling.
- Curing: The concrete is allowed to cure for a specified period, during which it gains its strength.
- Stripping: Once the concrete has reached sufficient strength, the formwork is removed.
Importance of Formwork Quality
- Structural Integrity: High-quality formworks ensures that the concrete structure is structurally sound and can withstand loads.
- Dimensional Accuracy: Precise formworks is essential for achieving the desired dimensions and tolerances.
- Surface Finish: The quality of the formworks directly affects the surface finish of the concrete.
- Efficiency: Well-designed and constructed formwork can improve construction efficiency and reduce costs.
By understanding the principles of formwork, construction professionals can ensure the successful completion of concrete structures of all sizes and complexities.
Formwork systems can also be classified by the type of concrete structure they support, such as slabs, columns, or walls. Some common types of formwork systems include: System column formwork, Horizontal panel, Slipform, Jumpform, and Vertical panel systems.
