Formwork is the term given to either temporary or permanent molds. They are generally used to allow concrete or similar materials to be poured into. Formwork is used when construction teams need to hold wet concrete in place until it hardens to the desired shape. It must have the necessary strength and have the ability to withstand a huge amount of weight.
Metal beam slab formwork
It is similar to the traditional method; however stringers and joist are replaced with aluminium forming systems or steel beams. The supports are replaced with metal props. This makes this method a little more systematic and reusable. Aluminium beams are produced as telescoping units. This allows them to span supports that are located at different distances apart.
Modular slab formwork
These systems consist of prefabricated timber, steel or aluminium beams. The beams and formwork are set by hand and pinned, clipped, or screwed together. The advantages are:
It does not need a crane to place the formwork. Formwork modules can be removed after concrete sets leaving only beams in place prior to achieving design strength.
Table or flying form systems
They consist of slab formwork “tables”. They are reused on multiple stories of a building without being dismantled. The gaps between the tables and wall are filled with “fillers”. The use of these systems greatly reduces the time and manual labour.
A table is built pretty much the same way as a beam formwork except that the single parts of this system are connected together. The way it’s connected allows for easier transportation. It can be made using plywood, aluminium or steel. The joists are either made from timber, aluminium or steel. These decks are generally rectangular but can be other shapes too.
All support systems have to be height adjustable. This allows the formwork to be placed at the correct height and to be removed after the concrete is cured. Some systems combine stringers and supports into steel or it combines aluminium trusses. While other systems use metal frame shoring towers. Formwork decks can also be attached to previously cast walls. This eliminates the use of vertical props altogether.