Formwork refers to the moulds used to contain and shape wet concrete until it dries and is self-supporting. From the early beginnings of construction and architecture, formwork makes up an essential ingredient to any construction project. The Pantheon in Rome, which began construction around 27 BC, is a notable example of the early use of formwork to create magnificent and long-lasting concrete structures. Despite this, formwork was mainly used in masonry due to the difficulty and limited production capacity of concrete. It wasn’t until the mid-19th century, after Portland cement was invented, that concrete became the favoured choice for building materials.
Formwork also includes the forms within which the concrete is poured, and the frames and bracing which provide stability while the concrete is drying. The joists, bracing, bearers, foundations, and footings which make up the formwork assembly are technically referred to as falsework. The way in which formwork is constructed presents high risks to workers, as they need to work at heights, operate mobile cranes, and excavate foundations.
The introduction of technology has made formwork much safer and easier to construct and use. Generally, the simpler the structure, the safer it is for workers to construct, assemble, and disassemble the formwork. Hence, the design of the concrete structure plays a central role when considering the health and safety risks involved during the entire construction process. It’s essential that designers account for work platforms and special equipment needed to ensure safe formwork construction. Designers must also use technical standards and engineering principles that meet the regulatory requirements for formwork, which state that formwork should be:
- Rigid, watertight, braced and tied together to maintain position and shape during construction; and
- Able to be removed easily and safely without damaging the formed concrete, or have components that remain as part of the finished structure so the rest can be removed without damaging the structure.1
Formwork can be manufactured from a large variety of materials. While timber is the most commonly used material, steel and plywood are becoming more prominent due to the increasing costs and depleted reserves of timber. In recent times, materials like plastics and fibreglass are also being used. Ultimately, the type of formwork used is dependent on the nature of the structure along with costs and availability of materials. Formwork can generally be classified into two types: traditional formwork and modular formwork.
Traditional formwork is normally constructed from timber or plywood and supporting structures like scaffolding. While timber formwork is easy to manufacture, it is time-consuming and has a short life-span (roughly 10 – 12 projects). As a result, traditional formwork is still predominant in places where labour costs are cheaper than buying long-lasting reusable formwork. In traditional formwork, a standard formwork frame should be used whenever possible which has a known tested loading capacity. These frames reduce the health and safety risks to workers who need to erect and dismantle this type of formwork.
As opposed to traditional formwork which is constructed on-site, modular formwork is manufactured offsite and is typically made from plastics, aluminium, steel, and hardboard products. There are normally two or more materials used to construct modular formwork, such as plywood facing to steel frames for wall panels. Modular formwork is often lighter in weight which makes assembling and dismantling much easier for workers, along with reducing the risk of injury. The only disadvantage of modular formwork is that it is more susceptible to falling over during the erecting process as a result of wind loading. This issue can be mitigated however, by progressively bracing the system according to the supplier’s guidelines.
While formwork is crucial to any construction project, the process presents many health and safety risks to workers so it’s paramount that all staff have the relevant licensing and training in accordance with the standard AS3610: Formwork for concrete. Safety is always the leading priority in any construction project, so if you require any assistance in obtaining the relevant qualifications to work with formwork, get in touch with Uni-Span on 1300 882 825, or visit their website for further information: http://uni-span.com.au/