Comprised of 399 individually cut limestone pieces, unreinforced and assembled without mortar, the Armadillo Vault spans 16 meters with a minimum thickness of only 5 cm. Its funicular geometry allows it to stand in pure compression, while tension ties equilibrate the form. Starting from the same structural and constructional principles as historic stone cathedrals, this sophisticated form emerged from novel computational graphic statics-based design and optimization methods developed by the project team.

The Armadillo Vault was the centerpiece of the “Beyond Bending” exhibition at the 15th International Architecture Exhibition – La Biennale di Venezia, curated by Alejandro Aravena, which was held in Venice, Italy, from May 28 to November 27, 2016.

The engineering of the discrete shell used innovative computational approaches to assess stability under various load conditions. Each stone voussoir is informed by structural logic, by the need for precise fabrication and assembly, by the constraints of a historically protected setting, and by limitations on time, budget, and construction. The voussoirs are designed to be planar on the exterior to avoid the need to flip the stones during machining. Their interior sides’ doubly curved geometry was obtained through rough cutting. Rather than milling away the excess material left by this process, it was instead hammered off, leaving the resulting grooves as an expressive feature.

The shell’s dual appearance, scale-like on the outside and softly curving on the inside, is thus a direct materialization of the project’s hard constraints. Standing without reinforcement, proportionally as thin as an egg shell, the expressively flowing surface structure challenges the idea that complex, freeform geometry need go hand-in-hand with inefficient and untruthful use of material.