The Use of Sliding Formwork and Its Benefits in Construction

The Use of Sliding Formwork and Its Benefits in Construction

Shuttering is vital to shape tall concrete structures, but static shutters are impractical above a certain height, and sliding formwork is the only option. Skyscrapers have long been a familiar part of the skyline in cities worldwide. However, until the early 1900s, their construction was an extremely time-consuming and costly task. Each floor had to be built separately and given time to stabilise before removing and relocating the shuttering to start building the next.

Slip forming, as the technique is commonly known, employs a formwork system that can be raised gradually as the concrete cures without the need to assemble, dismantle, and relocate it repeatedly. Because the shuttering moves continuously, the process eliminates visible joints. Also, the shuttering can be adjusted to change the taper or thickness of the structure on the fly. The technique was first used in 1910 for building silos, cooling towers, bridge piers, and dams in the US. In 1969, the method was adopted to create the Sheraton Hotel in Waikiki, Hawaii, heralding a new era in construction history.

The Evolution of Sliding Formwork

Though unsuitable for all concrete structures, in addition to the abovementioned applications, slip forming has since been adapted for use in horizontal structures like pavement kerbs, airport taxiways, and cycle paths. However, the technology underpinning slip forming has also evolved considerably.

The initial use of manual labour to operate the hydraulic systems required to raise the shuttering is no longer necessary. Instead, modern slip-form shuttering employs motorised jacks, automated control systems, and advanced materials to ensure smoother and more precise operation.

In general terms, slip forming is an efficient and economical option for structures over 16 metres high and at least 15 centimetres thick. When appropriate, the form can be raised by 5 to 30 centimetres per hour or between 1,2 and 7,2 metres per day, a build rate well beyond the capabilities of any other current construction method.

Some Benefits of Sliding Formwork

Slip formwork offers multiple benefits, including the following:

  • Economy: The process significantly reduces construction timelines, resulting in considerable cost savings.
  • Precision: The automated adjustment of sliding formwork enables the precise control necessary to ensure uniformity and structural integrity, thus minimising the need for remedial work.
  • Speed: The continuous process allows work to continue around the clock and in all weathers.
  • Safety: Eliminating the need to assemble manual formwork at heights reduces the risk of accidents.

Sliding formwork has transformed the process of building tall structures, improving their quality while cutting costs. Contact us at Disc-O-Scaff for all your formwork and scaffolding requirements and transform your building projects.

The Nature, Use, and Benefits of Concrete Shutters in Construction

The Nature, Use, and Benefits of Concrete Shutters in Construction

While the invention of concrete revolutionised construction, this would not have been possible without concrete shutters to mould it into walls and columns. This greyish mixture of cement, water, air, and aggregate may lack the more attractive appearance of red brick, but it is equally strong and durable while being far more versatile.

In its uncured, wet state, the mix can be readily formed into any shape an innovative architect can dream up. However, maintaining that shape during the curing process requires using a support system known as formwork. The term is generic. It applies to any means of forming shapes from concrete and includes a type of temporary mould known as shuttering, the system used to create vertical structures from poured concrete.

Because shuttering must usually be removed once the contained structure is stable, it must be composed of separate interlocking parts. However, the freshly poured concrete will exert extreme pressure on the surrounding formwork, so it must be made from a suitably durable material. Furthermore, the joints between its component parts must be tightly sealed to prevent the wet concrete from leaking.

Historically, first timber and, later, plywood were used for this purpose, and the latter is still used today by some builders. However, although wood proved strong enough for the task, it is subject to warping and rot from repeated exposure to dampness. Consequently, concrete formwork made from wood has a limited lifespan.

The Benefits of Using Steel to Create Concrete Shutters

Materials science is a constantly and rapidly evolving field responsible for advances in areas as diverse as joint replacement surgery, battery design, aerospace, and the components of formwork used by construction companies. In the latter case, there are three contenders for a more effective alternative to wood.

  • Plastic: PVC shuttering has several attractive benefits. It is light, water-resistant, easily assembled and dismantled, and reusable. However, it’s more expensive than timber or plywood and has lower rigidity, strength, and bearing capacity than metal alternatives.
  • Aluminium: The metal is abundant and is, therefore, a more sustainable option than plastic. However, although it is also a lightweight material, it is easily dented, significantly more expensive, and its production has a high environmental impact.
  • Steel: Despite being the heaviest of the three, steel concrete shutters are also the toughest and most durable. It is also the most versatile and easiest to assemble and disassemble, making it the preferred choice of leading construction companies worldwide.

Purchasing Quality Concrete Shutters

We at Disc-O-Scaff are South Africa’s foremost manufacturer and supplier of steel formwork. Contact us for more information about our SABS-approved products for the construction industry.

How Column Formwork Revolutionised the Use of Concrete in Construction

Concrete appeared in 6500 BC when Jordanians and Syrians used it to lay floors. Later, the Romans’ use of column formwork transformed construction forever. For almost seven millennia, due to its semi-liquid nature when first mixed, the use of this aerated mixture of cement, water, sand, and gravel was limited to two dimensions.

The iconic building material only began to reveal its full potential when Roman ingenuity led to the use of simple moulds made from materials like reed and fibre to secure the uncured mix in place until set. Gradually, Rome evolved from a brick-and-mortar city to a concrete metropolis. The fact that much of the Pantheon and Colosseum remains standing today is ample proof of the value of even this primitive formwork. Surprisingly, it was only after the fall of the Roman Empire that timber was first used for this purpose.

Column Formwork in Modern Construction

Columns and pillars are frequent features of modern construction products, like bridges, tunnels, motorway overpasses, and multi-storey car parks. These vertical elements must support and transmit the compressive and bending forces from the infrastructure above to the foundations below, so their integrity is crucial. Longitudinal steel bars and brackets within these structures help resist flexion and prevent buckling, while the external column formwork determines the desired shape.

Smaller builders still use timber and plywood formwork, but although it’s cheap and versatile, it absorbs water and may tend to shrink or deform, limiting its useful lifespan. However, the introduction of steel in the early 1900s provided builders with an option that was strong, easy to use, and which, with only minimal care, could be reused repeatedly.

Despite the introduction of aluminium formwork in the 1960s and the arrival of plastic versions in the early 2000s, steel has remained the option of choice for most large construction companies. While aluminium is lighter and cheaper, steel is stronger and more durable.

Column Formwork from Disc-o-Scaff

All formwork manufactured by us at Disc-o-Scaff is engineered to the highest standards using only SABS-approved materials. You may find a cheaper product but not a better one, which might explain why our products have become the preferred choice of so many leading South African construction and scaffolding companies.

We offer two high-quality column formwork products:

  • Circular Column Box: These can be supplied in various sizes to create circular columns.
  • Economy Panel Column Box: For creating square or rectangular columns of various sizes with just four components.

If you want quality and value for money, phone us, email us, or complete our online contact form to learn more about world-class formwork and scaffolding from us at Disc-o-Scaff.

Basic Working Principles of Formwork in Construction

With concrete being the main choice of building material, formwork has introduced complex geometric designs and formidable-sized construction in urban development. This symbiotic relationship has proven that the architectural landscape can be built structurally sound, sustainably, cost-effectively, and at a faster pace.

As the leading formwork manufacturer, we at Disc-O-Scaff would like to emphasise the importance of quality formwork and the possible failures that could occur if incorrect shuttering is selected to build structural elements, such as beam and column formwork.

Factors that Can Affect the Quality of a Surface Finish, Especially in Formwork Applications

The method of using and handling formwork significantly impacts the finish of concrete. Obvious surface blemishes, such as poor form joints, offsets, and the use of inadequate facing materials, occur when the formwork material selection is unsuitable for the construction of the structural element. Achieving a high-quality concrete finish depends heavily on factors such as the concrete mixture, concreting temperature and practices, as well as careful formwork considerations before and during construction.   

Freshly poured concrete exerts lateral pressure affecting the height of the concrete formwork. The pressure of the formwork increases as the height of the fresh concrete increases and only ceases when further force from above is no longer transmitted. Should the incorrect formwork have been selected, this continuous rising pressure could result in sections of the formwork bulging or deflecting.

Causes of Concrete Formwork Failure

Several factors can contribute to the failure of formwork during and after construction, which need to be highlighted to ensure that these indispensable building structures remain structurally safe supports.  

  • Lack of Inspection

Often, failures occur due to inspection by unqualified or inexperienced inspectors. A competent person or engineer should always be on-site to inspect and certify that completed formwork meets design specifications and that it is structurally sound before it is loaded.

  • Improper Connections and Defective Components

As much as formwork can fail due to design flaws that do not take lateral forces and stability into account, a lack of maintenance will also lead to failure. Shuttering is used multiple times, and often, corrosion sets in and damages occur which, during assembly, are not always considered. If components are insufficiently connected with the proper wedge and clip assemblies, it can lead to progressive collapses and compromise the integrity of the formwork.     

  • Premature Removal of Components

Tight scheduling and budget constraints may lead to the premature removal of the shuttering. Formwork must only be removed once the concrete has adequately cured.

To safeguard against formwork failure, we at Disc-O-Scaff would advise that the correct procedures are followed during the assembly when the concrete is being poured, and once the concrete has cured, the formwork has been deemed safe to remove.

Armed with this knowledge and trusting your formwork solutions with the experts in the industry, we at Disc-O-Scaff will ensure that your choice of circular, economy panel, and column shuttering will provide ample structural support. Contact us for superior-quality steel scaffolding and formwork solutions.