Rethinking structural masonry: unreinforced, stone-cut shells

Recently, the interest of architects and designers in contemporary applications of masonry has increased considerably. Motivated by the elegance of historic masonry structures, mostly decorative stone and brick applications have been developed, driven by new possibilities in fabrication technology and the increasing relevance of sustainable building materials. In contrast, the use and potential of structural masonry has rarely been addressed in these developments. This paper presents novel methods for structural stone masonry, focusing on the possibilities of approaches closely interrelating form-finding and material-driven fabrication. Thanks to newly developed structural form-finding methods for the design of unreinforced masonry shells, new, ‘free-form’ vaulted structures in stone are now imaginable. These new structural design tools have been integrated into a digital process, which is informed by relevant construction and fabrication parameters. The paper focuses on this interrelation, linking expressive structural form to its real-world demands in stone construction by considering appropriate and efficient fabrication technology. The design for the MLK Jr Park Vault in Austin, Texas, USA is used as a proof-of-concept case study for the process, taking full advantage of modern stone-cutting technology and using the compression strength and weight of stone masonry to efficiently combine construction material and structural form.