Rib-stiffened funicular floor system

This research develops the structure for an unreinforced concrete floor consisting of a thin funicular vault stiffened by a system of spandrel walls on its extrados. The structural prototype is completed with tension ties, which link the supports and absorb the horizontal thrusts of the funicular shell. It is a prototype for the NEST-HiLo project to be realized in 2015-16 in Dübendorf, Switzerland.

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The solution is inspired by built examples in tile vaulting in which thin vaults are stiffened by diaphragms, also called spandrel walls. In the present structure, this structural system is implemented and constructed in high-performance concrete to achieve an extreme thinness (2 cm in the case of this prototype for both vault and ribs) and to resist asymmetrical loading.

This floor would thus save more than 70% of the weight compared to traditional, 25-30cm-thick concrete floor slabs used in the construction of framed buildings. This directly lowers the requirements for the foundations (often a dominant resource and cost factor), but also enables lightweight building extensions and a reduction of total floor height, offering possibilities to address, among other issues, the vertical densification of cities.

A form-finding and analysis procedure for the design of such floor systems is presented, which consists of consecutive topology, shape, and size optimizations.

This floor will be demonstrated in HiLo: Research & Innovation Unit for NEST.


Liew A., López López D., Van Mele T. and Block P.Design, fabrication and testing of a prototype, thin-vaulted, unreinforced concrete floor,Engineering Structures,137: 323-335,2017.
López López D., Veenendaal D., Akbarzadeh M. and Block P.Prototype of an ultra-thin, concrete vaulted floor system,Proceedings of the IASS-SLTE 2014 Symposium,Brasilia, Brazil,2014.


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