Italy-based New Fundamentals Research Group designed and built a full-scale prototype of an experimental barrel-vaulted stone structure for SNBR, a French company that specializes in cutting-edge stone construction.
The structure is named Hypar Vault in a reference to the geometry of its constituent blocks; it uses two types of prefabricated stone modules—one type is the mirror image of the other—whose designs are based on the hypar (hyperbolic paraboloid), one of the only “doubly-ruled” surfaces in geometry. The use of these configurations allowed the vault to be constructed with almost zero wasted stone.
The modules were cut out of larger blocks of French limestone by means of wire-cutting technology using a robotic arm. Axial perforations were made in the blocks’ trapezoidal forms to account for the passage of stainless steel cables inside.
Once fabricated, the modules were hoisted up and put in place atop a vaulted wooden framework where they were joined together. Next, the framework was removed, and the structure was pre-stressed—steel cables were inserted, tensioned using a stress pump, and ultimately anchored to the base of the vault.
A strong area of focus is the subject of additive manufacturing to obtain hypar blocks—using waste limestone from processing stages to obtain recomposed stone through the mold and counter-mold technique, and subsequent fabrication by 3D printing, again using waste stone and cement.