W alk through any construction site and the scene that greets you is the presence of hordes of labourers working with construction materials. Many a time shacks prevail on the borders of the site, housing the labour. Dust and accompanying chaos is an integral part of this scene.
What if all this can be changed, the construction site left clean sans the mess, with only engineers and machinery present, the building coming up at a pace hitherto unimagined. Sounds like a fairy tale? Perhaps not. Not if the 3D monolithic modular technology that is fast gaining popularity is opted for.
A technology widely in use in countries like Singapore and Australia, it is now being tested in India, the Tata Housing Boisar project having already adopted it, the multi-level housing complex completed within 33 days. The technology, with its range of possibilities, offers the prospect of bringing in a paradigm shift in the construction techniques hitherto adopted in the country.
Under this technique, the structure is not based on beams and columns with accompanying hollow block walls. Neither does it involve the use of concrete slabs with their multiple joints, which is currently quite popular. Instead, the entire volume of the space is pre-cast based on the specifications and dimensions given and fitted in as individual modules.
These 3D components in the form of modules are stacked together, eventually forming the entire multi-storeyed building. Since columns and beams do not prevail in this technology, the entire volumetric modular system serves as the load bearing structure for the building.
Explaining the technique of the modules, S.J. Vijay, Director, hoMMission India, says, “There is a casting yard at the site where the modules are done based on the given specifications. The manufacturing here is standardised, with the reinforcement connecting the entire module. This means that every square foot of the structure of the building is reinforced, interconnecting the entire building, ensuring it does not collapse easily even in the case of natural disasters.”
Monolithic piece
He further adds, “Unlike in the case of concrete pre-cast slabs that require multiple joints, here each module is fitted perfectly into a 30mm drop, with no multiple joints. The entire module is cast as one monolithic piece. The plumbing and electrical conduits are all planned and fused into the module before the casting. The quality as well as the finish is also retained as the casting requires the use of M40 grade concrete as against the conventional M25 grade or less. This, together with the reinforcement, makes the structure strong enough to last a century.”
It is natural to assume technology comes only at a price. Vijay allays such fears, pointing that the cost per square foot is the same as conventional construction.
“The advantage is the speed of construction as well as the assured quality. Operating with unskilled labour not only raises quality issues but also comes with problem of labour shortage as well as delays which the construction industry is currently battling with. This technique is driven totally by engineers and machines.”
Commenting on the technique, Architect Shyamala Prabhu, Chairperson, IIID Bengaluru Chapter, says, “This technology would be suitable for affordable housing units where standardisation is the norm. In high-end developments, customisation is the key and in many cases a strong leaning to bring in traditional materials and designs is prevalent where this would not be relevant. Even where customisation is possible, the cost may not match the conventional approach.”
Vijay, however, refutes this contention, pointing that while the structural element is prevalent in every centimetre of the module, “The strength lies in the corners, just as in the column and beam grid. If spaces need to be opened up, the walls can be removed after leaving 30cm on either side.” As for bringing in differential designs that are not confined to a box form, he avers, “The moulds can be cast based on these differential specifications.”
Says architect Leena Kumar, Chairperson IIA Karnataka Chapter, “In a country which is abounding with unskilled labour, requiring to be employed, the construction industry serves as a vital source for employment. Replacing labour with machines may not be the option at this point of time. Besides, labour comes with its own individual unique skill sets which are effectively employed. Using this technique for individual units where design and customisation serve as the key, many a time linking to traditional modes and materials, currently may not serve to be a suitable option.”
Vijay, not surprisingly differs. “We will soon have villas done in a month, the structure complete in a week. And if the affordable housing target set for 2022 is to be met, the 3D monolithic modular technology is the answer.”
If the current interest evinced in the technology is to go by, Vijay may prove to be right.
