The barrel vault marks the beginnings of structural integrity, and retains a symbolic purpose even as technology supersedes it
The barrel vault is the most elemental and ancient of the vaulting types, documented from as far back as 4000BC; it was used by the Mesopotamians, Egyptians, Nubians, and Romans. Essentially a row of adjoining arches repeated to cover a given distance, allowing for the spanning of far greater distances than stone post-and-beam construction, barrel vaults are archetypal units of spatial enclosure that speak of the very beginnings of structural ingenuity. Prefiguring the spatial gymnastics of the groin vault and subsequent feats where ceilings soar to span vast distances in any number of ways, this form of enclosure has managed over countless centuries and across continents to achieve a number of impressively grand spatial feats, while always retaining an inherently elemental, historically rooted clarity. Even as technology has advanced, and the form of the barrel vault has become to a large degree structurally redundant, architects consistently return to its recognisable contours as an atavistic anchor, stabilising their innovations and architectural experiments in the millennial shadow of countless precursors.
This was the greatest of the Roman vaulted structures: in fact, the largest interior space the ancient world was to see. Here, the combination of imperial scale, coffered concrete technology and the barrel-vault form was unmatched until the Renaissance; from then onwards, its coffering has been consistently imitated. In terms of the use of concrete, the basilica’s design was not superseded until the 20th century.
Marking a return to the orderly grandeur of Roman interiors after centuries of gothic structural gymnastics, Sant’Andrea is an intriguing hybrid of the longitudinal Basilica of Maxentius and a centralised temple. The nave is effectively the same as the Maxentian progenitor, with six barrel vaults set perpendicular to a wide nave. The high barrel vault of the nave then continues, beyond a dome, to form an apse and pair of transepts arranged around the crossing, thereby combining two discrete classical types into a newly unified Catholic typology. This particular arrangement proved highly influential during the Church’s counter-reformation building programme.
Several of the new train stations built in the US at the beginning of the 20th century for the country’s continent-straddling network were directly inspired by Roman architectural precedents, particularly basilicas and bath complexes. Ticket halls were festooned with spectacularly super-sized versions of classical vaulting, suspended and hidden below steel-truss superstructures that allowed for the immense new industrial-imperial sense of scale. The 19th century architectural divorce between the ticket hall and accompanying front-facing buildings, which could be convincingly orchestrated as Roman baths or gothic conceits, and the vast concourse sheds which leapt over the multiple tracks behind them in steel and glass, was overcome in the concourse at Washington Union Station. The shed is here signified by the architect as a shallow and impossibly vast barrel vault through the use of coffering. This alternates with glazed regions that reveal the nature of the steel structure behind; in a theatrical game of historical allusion and engineering bravura where neither dominate, both instead complement one another to create a rarely-achieved visual union of technological prowess and architectural-historical lineage.
Corbusier here used the barrel vault to signify both an earthy rootedness in the earliest modes of construction, as well as an affinity with the no-nonsense jack-vaults of the previous century’s warehouse and manufacturing complexes. Using the vault as the base unit of spatial organisation in the houses, their additive composition strongly recalls the hand-made, warren-like cumulative quality of ancient vernacular examples. In structure of the vaults are a hybrid of masonry and concrete: spanning tiles are used as permanent formwork for the concrete poured above, bringing the Roman technique of brick-faced poured concrete previously employed at vast scale to the intimate interiors of a domestic environment.
Here, Fathy’s work embodies both some of the earliest, vernacular forms of barrel vault construction and their 20th century rediscovery which he pioneered. In contrast to the Roman, Renaissance and historicist civic complexes or bijoux private gems of the 17th to 20th centuries, Fathy was interested in how villagers in North Africa and elsewhere, without architects or engineers, had through the millennia harnessed elements as simple as local soil, water and the sun to build environmentally performing, spatially-impressive complexes using a variation on the barrel vault. Built from sun-dried mud bricks, each of the arches that join together to form the vaults in these constructions is tilted in the vertical axis, leaning on one another incrementally. This means that the building process does not require any centring to hold it as it goes up, reducing the amount of material required in the build and making the whole endeavour much simpler. By leaving either end of the vaults open with a screen, hot air accumulated inside during the day can rise and escape at night, naturally cooling the interiors.
In the Kimbell’s design Kahn was alluding to the proportions and clarity of longer types of Roman barrel vault, particularly certain examples of cryptoporticoes (below-grade barrel-vaulted service corridors) with their immersive sense of enclosure and eerily indirect light. The Kimbell’s vaults are vaults in the sense that the image they give visitors is of a space very much rooted in that tradition; however, structurally speaking, the ceilings are instead extremely long post-tensioned concrete beams. Kahn required his ceilings to span distances of up to 30m without any support, something impossible for a vault which needs continuous counteracting forces along its full length. This creates a visual tension, highly pleasurable for the viewer, who simultaneously recognises the ancient form of the barrel vault while also being struck by the strangeness of its being lifted off the ground, impossibly weightless and impossibly long.
Referring to the lightness and perforations of Japanese screens, the structural form of western barrel vaults, and the lightweight architectures of science fiction and the high-tech, Ito’s house from 1984 embodies the light-touch synthesis of contradictory themes he would continue to explore throughout his career. Migrating to Japan and inserting itself within a complex form of postmodernity, the vault here lives on as an echo of itself, translated into a new language in which it is just one of many equal adjectives in a vocabulary that forms its phrases out of words from every period, every culture and any place. The image is of a second version of the design executed by Ito in 2008 at his Museum of Architecture.