Nov 14

Why Wouldn’t You Use Modular Slab Formwork Systems?

Modular slab formwork has been around for decades however surprisingly it is not in frequent use within smaller tier 2 and tier 3 concrete formwork contractors within Victoria. This brief article will highlight the benefits of using modular slab formwork as opposed to traditional methods for suspended slab formwork.

Conventional Slab Formwork/Falsework

Conventional Slab Formwork Construction

Modular Slab Formwork

Modular slab formwork can come in an array of forms, each of which has their merits. Lifeform formwork systems are considerably less labour intensive than conventional methods to set up and strip. They require plywood to be laid over the modular panel joists allowing for an excellent class of finish.

Liteform Modular Formwork

Liteform Modular Formwork System

Slabform formwork systems allow for further labour savings as panels come prefabricated with plywood. Installation of both becomes systematic once the learning curve is passed which can then significantly increase efficiency.

Slabform Modular Formwork

Slabform Modular Formwork System

A significant benefit that is perhaps not as well understood with contractors who are unfamiliar with modular formwork systems is the stripping advantages. Many of the more recent modular systems such as Liteform and Slabform incorporate drop heads with propping. Drop heads allow the beams and panels to be stripped. With a simple blow of a hammer, part of the drop head supporting the formwork beams ‘drops’.  The beams and panels can then be re-used on the next section while the props remains in place supporting the recently cast slab undisturbed.

This can often be done when the slab is said to become ‘self-supporting’ which could be as soon as 4 days. Note that this depends on a range of parameters such as design capacities, construction loads, slab depth, prop spacing and temperatures and so is project dependent.

The advantage with this stripping technique is that it is fast. The contractor does not have to carefully remove small amounts of formwork and re-prop (re-shore) to free up some shoring equipment. The procedure is safe and reliable. It allows the reuse of the beam and panel components for upper levels with additional propping. This has the potential to save on half the formwork equipment required for a multilevel structure when we consider the optimised propping and components used compared to conventional methods.

Further benefits become evident once the formwork system is in place. The optimised spacing of propping and beam capacities reduce congestion whilst in place. This depends on the depth of slab to be formed and construction load but can be as great as 3m X 1.5m, which caters for movement much more effectively than 1220×1524 or 1829 frame bays with cross bracing.

Slabform Falsework Uncongested

Reduced Congestion Under The Slab

Crane utilisation is significantly minimised when compared to using table forms with all components weighing less than 16kg and therefore capable of being installed and removed by hand. The formwork system requires only basic components including, propping, beams, panels, bracing and/or wall mounts to substitute majority of conventional frames, braces, base jacks, U-heads, bearers, joists and plywood.

Modular formwork systems can be braced assuming effective top restraint where fixings to the permanent structure are used to provide stability. In the event that this is unauthorised by the project engineers bracing between propping in strategic locations will provide stability and allow the falsework to support all the imposed lateral loads required.

Modular Slab Formwork Systems vs Conventional

With the aid of proprietary accessories, modular Slab formwork systems can easily accommodate infills around columns or handle complicated edges to match required project dimensions. They can also easily match in with other modular slab formwork systems or traditional methods where needed.

Modular Formwork Systems have a short learning curve, and when we consider the basic components and the systematic process that comes with repetition, they require less skill to install and the chance for error is greatly reduced. This is further magnified thanks to the reduction in labour due to the speed of assembly. Naturally Cassaform offers exceptional support and service to help you get up and running quickly.

For contractors who utilise their own conventional formwork equipment, trying a modular formwork system while their equipment is idle can be difficult to do. However, when you consider the cost saving associated with a reduction in the cost of labour and reduction in the purchase of Formply and other consumable items, the cost of using a conventional system is often significantly higher. This is more evident in multistorey/ repetitious structures.

Not fully understanding the formwork systems constraints and limitations combined with the perceived fear that it will ‘simply not work’ or that it is ‘too hard’ is creating a divide between formwork contractors. The information, support and service is there to help integrate these systems within our industry and for those who seek out and take up these innovative opportunities the rewards will come. If you would like to find out more about Modular Slab Formwork Systems and how they compare to Conventional Systems, Please Call Cassaform on 1300 745 674.