The structural principle of the Smart Slab is a hierarchical grid of post-tensioned ribs cantilevering from the Mesh Mould Wall.
(Photograph: ETH Zurich / Andrei Jipa)
Formwork production is the most labour-intensive step in concrete construction, particularly for non-standardised components. Since concrete is relatively cheap and readily abundant, the temptation is for the construction industry to produce the same solid ceilings over and over again, but the disadvantage is excessive material consumption and implicitly, a big carbon footprint. Digital fabrication methods can make a key contribution here: components can be optimised, enabling the necessary stability with far less material. The geometric complexity of a component does not matter in 3D printing, nor does it cause any additional costs – the printer simply prints what it is told to.
Computational design coordinates parameters
Dillenburger’s research group developed a new software to fabricate the formwork elements, which is able to record and coordinate all parameters relevant to production. In addition to basic data such as room dimensions, the researchers also entered a scan of the curved wall, accurate down to the last millimetre, which acts as the main support for the concrete ceiling. With the software, one could adapt the geometry of the slab so that at each point it was applied only as thick as structurally necessary to support the force flow. “We didn’t draw the slab; we programmed it,” says Mania Aghaei Meibodi, Smart Slab project lead and senior researcher in Dillenburger’s group. “It would not have been possible to coordinate all these aspects with analogue planning, particularly with such precision.”
If you look at the ceiling from below, you see an organic ornamental structure with different hierarchies. The main ribs carry the loads, while the smaller filigree ribs are mainly used for architectural expression and acoustics. Statics and ornamentation go hand-in-hand.The lighting and sprinkler systems are also integrated into the slab structure. Their size and position were similarly coordinated with the planning software. In this way, the building technology disappears elegantly into the slab to occupy very little space. This saves only a few centimetres in the DFAB House project, but in high-rises this may mean a few extra floors could be fitted into the same height.
Fabrication at the push of a button
