Industrialization stimulated a generative relationship between structure and architecture. Ideas federated from both disciplines forged rational and robust buildings through the rigorous repetition of components and assemblies. Networks of linear lightweight members, monolithic waffle slabs and ribbed shells symbolize this union’s aim for maximum architectural space with minimal material use.
All manner of reproducible elements were knitted into rigid textile-like curved or planar surfaces «packing space» as Buckminster Fuller would articulate using his tetrahedral truss. Triangulation, truss effect and materialized lines of stress symbiotically increased structural inertia and stability. These modular grids and networks argued in favour of prefabrication in skeletal frameworks, in timber or steel, as well as in lamella vaults and filigree domes. Ribbed surfaces allowed similar optimizations in monolithic concrete structures, exposing a lattice of beams, girts and sustaining segments. In medieval ribbed vaults, compressive lines of stress materialized load transmission. These spines can be formed with equivalent or varying depths to further express load transmission. A beautiful play on structural rhythm, the waffle slab used by Louis Kahn in the Yale Art Gallery in New Haven, Connecticut or John Lautner’s modern masterpiece, Sheats–Goldstein Residence, came to characterize modernism with its rhythmic sequence and gothic imagery. Cast in orthogonal, triangular grids or even more dynamically by Pier Luigi Nervi, all were deployed to reduce reinforced concrete’s prohibitive dead load (2400 kg/m3).
The simplest systems place and align dimensionally uniform prefabricated boxes over flat formwork to define a pattern of voids into which rebar is positioned and concrete poured, hardened and cured - the resulting waffle effect and criss-cross pattern buttresses a relatively thinner horizontal slab over the formed ribs. The formwork could be reused or left as part of the structure’s geometry if made of some type of thin shell material. The voids from waffle forms could be used for architectural lighting to amplify the systemic patterns.
Today, digital technology allows for this type of structural rationalization to develop ideal patterns and link this data to code machines to create specific formwork components to further optimize ribbing or arching patterns.
Left: Yale Art Gallery; right: Sheats-Goldstein residence
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