Chair of Digital Building Technologies, Chair of Physical Chemistry of Building Materials, Chair of Structural Design, ETH Zurich
The Smart Slab enhances the excellent structural properties of concrete with a radical new aesthetic enabled by the 3D-printed formwork.
The pioneering construction method of the Smart Slab uses 3D-printed formwork for casting and spraying concrete in geometrically complex shapes. 3D printing overcomes the geometric limitations of traditional formwork fabrication methods. Furthermore, it enables the construction of integrative concrete elements with elaborate, free-form and highly detailed surfaces and smart construction details. 3D printing has the added benefit that geometric complexity and differentiation come at no additional production cost.
The Smart Slab is a 78-square-meter prestressed concrete slab discretized into eleven 7.4-metre-long segments. Each segment is unique and prefabricated with special interface features which facilitate on-site connection through post-tensioning tendons.
The geometry of the Smart Slab is structurally optimized for its challenging load-case, involving cantilevers of up to 4.5 meters. The material is distributed in a hierarchical grid of curved ribs, which vary between 30 and 60 cm in depth. In addition, the interstitial surfaces stabilize the grid and are only 1.5 cm thick. Consequently, the slab only weighs 15 tonnes, almost 70% less in comparison to a conventional solid concrete slab.