The use of poured concrete slabs for building structures has been around since the Roman Empire. Its strength and ability to be molded into specific designs and almost any geometry makes concrete versatile. The method of creating a base for holding the concrete until it can dry is called formwork. Formwork is classified into the following five distinct categories.
Material
Timber is very affordable, readily available, and offers excellent strength. It is understandably a popular choice for forms. The downside is that timber can absorb the moisture from the wet concrete if the project requires a lengthy drying time.
Another popular choice is steel. Steel offers a strong mold and can support heavy pours. Steel formwork is quickly and easily shaped and fixed. While the initial cost of steel is more than lumber, its repeated use can lower overall costs.
Plastic formwork may also be an option. Plastic is occasionally called for on certain projects. It cannot hold as much weight, it’s often more expensive, and can be prone to damage from exposure to the elements. But the result for developing a smooth finish or a complex shape might necessitate this more-costly material.
In recent years, the use of full Aluminum Formwork, particularly aluminum panels, has gained popularity. Aluminum formwork is often used in the structure of a building. The panels are strong and reusable. At the end of its usable lifespan, the aluminum can be recycled or sold as scrap, recouping some of the initial investment.
Size
There are generally only two sizes of formwork: small and large. These terms refer to the method by which the structure is put in place to receive the concrete. A small formwork is one that can be constructed by the workers manually. It is not uncommon for a single worker to take on creating small formwork alone. Large-sized formwork frequently requires the use of a crane to manipulate and move the supporting structures. They are often reinforced with studs or soldiers due to their weight.
Location
Some types of projects experience limited availability of formwork due to the placement of expected concrete elements. For example, a set of concrete stairs would require a complicated formwork to allow for the many dimensions associated with even a small staircase. Additionally, the absence of other foundational supports to secure the forms further complicate and limit the available options.
Nature Of Operation
Similar to size, the nature of the operation is another method for classifying concrete formwork. Does the formwork require equipment for the erection and striking processes? Some projects may also require horizontal movement using rollers, rails, or tracks. If not, then the formwork is likely operable manually.
Brand Name
The final classification of formwork is derived from the system or manufacturer patent. These include products from brands SGB, RMD, VSL, MIVAN, Thyssen, and Cantilever. These manufacturers are finding a great deal of industry support thanks to their advanced systems, estimating advice, innovative building methods, and various design options. As these companies experience more industry acceptance, the forecast is that these companies will continue to expand their services.
There are several considerations to weigh when opting for concrete formwork for a particular project. The design will be the driving force, but budget and site expectations have a say in the matter. When developing a construction plan for poured concrete structures, it’s essential to understand formwork classifications. This will ensure selecting the best choice for the project's success.