Smart Slab is the first concrete slab fabricated with a 3D-printed formwork. It is a lightweight concrete slab, displaying three-dimensional geometric differentiation on multiple scales. It combines the excellent structural properties of concrete with the geometric freedom of 3D printing which allows for the creation of highly optimised building components with complex structural configuration out of concrete.

The key benefit of 3D printing is that geometric complexity and customisation do not increase production cost and time. As limitations on the size and resolution of 3D-printed objects disappear, the technology becomes more relevant to life-size architectural construction. Smart Slab showcases a new generation of a radically optimised digital building processes from design to fabrication. It utilises 3D printing as a way to automate and optimise the most labour-intense process in concrete construction: fabricating the formwork. Through 3D-printed formwork, Smart Slab takes full advantage of the plasticity of concrete to create a highly optimised building component featuring intricate ornamental structures which create a rich architectural experience.

The 78-square-meter Smart Slab that is fabricated for the DFAB HOUSE cantilevers over the S-shaped Mesh Mould wall and carries the two-story timber unit above it. The Smart Slab comprises eleven 7.4-metre-long segments which are prefabricated and then mechanically joined using post-tensioning cables.

The geometry of the Smart Slab is structurally optimised for its challenging load-case, involving cantilevers of up to 4.5 metres. The material is distributed in a hierarchical grid of curved ribs, which vary between 30 and 60 centimetres in depth. The 1.5 centimetre thick concrete fields between these ribs are domed to maximise stability and to minimise the amount of material needed. Consequently the slab only weighs 15 tonnes, almost 70% less in comparison to a conventional solid concrete slab.

In Smart Slab, details for the façade interface and for technical installations such as sprinklers and lighting are embedded into the prefabricated elements to reduce construction height and to avoid complexity on the construction site.

Planning software was developed to integrate the fabrication parameters into the early design phase. This software allows for optimisation of the slab design, automatic detailing, cost control and the direct export of fabrication data relating to the formwork.

More Innovations

Project credits:
Leading investigators
Prof. Dr. Benjamin Dillenburger, Digital Building Technologies Group, ETH Zurich
Prof. Dr. Robert Flatt, Chair of Physical Chemistry of Building Materials, ETH Zurich
Prof. Dr. Joseph Schwartz, Chair of Structural Design, ETH Zurich

Contributing researchers
Dr. Mania Aghaei Meibodi (Project lead), Mathias Bernhard, Andrei Jipa, Demetris Shammas, Rena Giesecke, Jesus Medina, Melina Mezari, Matthias Leschok, Dr. Timothy Wangler, Nicolas Ruffray, Dr. Marco Bahr

Ana Anton, Patrick Bedarf, Philippe Steiner, Ioanis Fousekis, Lorenz Brunner, Leander Peper, Xijie Ma, Michael Lyrenmann, Philippe Fleischmann, Andreas Reusser, Heinz Richner, Prof. Dr. Eleni Chatzi, Vasileios Ntertimanis, Harmanci Yunus Emre, Prof. Dr. Andreas Wieser, Robert Presl, Eugenio Serantoni, Valens Frangez, Adi Grüninger

Industry partners
Bürgin Creations
Frutiger AG
voxeljet AG
Georg Ackermann GmbH
Stahlton AG
Christenguss AG
Fischer Rista AG
Rudolf Glauser AG
Gom International AG

Image credits:
Digital Building Technologies Group/ETH Zurich, Michael Lyrenmann, Catherine Leutenegger, or Tom Mundy. If you intend to use one of the images, please contact us for the exact image credits.