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Formwork is a crucial element in construction. But contractors need to be careful as most accidents are reported at the time of installation of formwork

Did you know it was the Roman engineers who first began using slab formwork to complete constructions that used concrete? Most of the construction was built using arches and domes because concrete does not have a strong resistance to stress. Concrete only became a popular material with which to build once reinforced concrete was invented.

Formwork is a complex technique involved in construction which requires specialist contractors for proper use. It’s the term given to specific moulds or receptacles into which concrete is poured to make slabs for construction or actual components of buildings. Surprisingly, for a technique that has been used for thousands of years, it still has no substitute. Vinayak Bhosle, engineer at Larsen & Toubro says: “If there is a substitute for concrete, then maybe formwork will find a substitute.”

While concrete is quite strong in resisting compressive loads, it has relatively poor tensile or torsional strength. Little wonder why the early structures mainly consisted of arches, vaults and domes.

Of the most notable concrete structure from early times is the Pantheon in Rome. Moulding these structures meant constructing temporary scaffoldings and formwork or falsework in the shape of the structure. Such techniques were not isolated to pouring concrete, but were and are widely used in masonry. Because of the complexity and the limited production capacity of the building material, concrete’s rise as a favoured building material did not occur until the invention of Portland cement and reinforced concrete.

Vinod Deshani, vice-president (engineering department), Kanakia Spaces says: “Formwork has evolved over the years in terms of materials used. However, formwork is necessary to create strong structures.”

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While wood is the most common fabric used, steel is gaining popularity considering that most developers are making maximum use of floor space index (FSI) and constructing high-rises. Because the system is easily dismantled into single parts, it is transportable.

The system is built in the same way as beam formwork, apart from these single parts. Joists and stringers are screwed, bolted or welded to become a deck. “Most of the construction techniques in India have mainly been borrowed from Europe.

In India, we prefer to use simple wood or plywood,” says Aniket Joshi, sales engineer, Peri India. “Bamboos are another material commonly used in India. The inherent strength of bamboos offers a tensility not seen in other materials. But this has a disadvantage – bamboos can tend to cave in, as once erected if can offer no access to the area underneath.”

The success of Billimoria’s Nagari Niwara Parishad at Goregaon in Mumbai proves that even unskilled workers could lift and erect a formwork if the material is right.

Billimoria opted to use lightweight aluminium formwork system of construction enabling in-situ casting of all the components of a dwelling unit including the walls, floor slabs, weather shades, lofts, parapets and staircase to form a monolithic structure which meet strict seismic requirements.

The resulting form finished concrete is highly durable and requires no further rendering. Especially when building low-cost mass houses, this system is the most cost-effective as a considerable repetition of floor layouts are required. Incidentally, system formwork is the checks that are carried out during designing or utilising a formwork.

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