Louis Kahn: Building and Being
Originally posted March 13, 2022
The Kimball Art Museum is one of the last few works designed by the renowned, mid-century architect, Louis Kahn. Completed in 1972, it is now fifty years old, and looks no different than the day it was finished. Louis Kahn spent most of his life as an academic at the University of Pennsylvania, completing his first major commission at age fifty in 1953. His knowledge of history was vast, and he was very much influenced by the French Enlightenment architect, Étienne-Louis Boullée. Some may be familiar with Kahn's library at Phillips Academy in Exeter, New Hampshire, which bears a strong resemblance to Boullée's metaphysical representations.
Left: Phillips Academy (Kahn)
Right: Cenotaph for Newton (Boullée)
The poetic impact of the Kimball is revealed in its details: the arisses in the concrete formwork, the recessed control joints, the lead coins in the snap tie plugs, the reveals at the travertine, the rivulet at the portico where it meet the pool. Each material retains its essential dignity. Missing are the caulked expansion joints, the filler pieces, the crimpled, metal edge strips of modern construction. Kimball is constructed of materials largely available to the Romans.
"You say to brick, 'What do you want, brick?' Brick says to you, 'I like an arch.' You say to brick, 'I like an arch too, but arches are expensive, and I can use a concrete lintel over an opening. What do you think of that, brick?' Brick says: 'I like an arch.'"
He is implying that materials themselves are embodied with intentionality. Discovering and respecting that intentionality is what brings a building to life.
None of this is to suggest a lack of sophistication and the vaults of the Kimball are a rather astonishing example of both a theoretical as well as empirical approach to a fundamental aspiration, that of bringing even, natural light into the galleries of the museum. It took several iterations to arrive at a vault that would deliver uniform light to the galleries, and it was August Kommendant, Kahn's trusted structural engineer and colleague, who finally proposed a cycloid vault with a brachistochrone curve.
A cycloid is the curve traced by a point on a circle as it rolls along a straight line. A mathematical formula attributed to the ancient Greeks, it also represents the fastest path of descent between a point A and a lower point B, where B is not directly below A, under the influence of a uniform gravitational field to a given end point in the shortest time. For a better understanding of this concept, see this demonstration.
It is useful to point out that the precedent for a top lit vault in concrete was the Pantheon in Rome, constructed in the first century A.D. which remained the longest concrete span in the world until the construction of the Palazzo Dello Sport in 1939 by the Italian engineer Pier Luigi Nervi. In achieving a longer span Nervi used a lamella truss system based on the coffering in the Pantheon.
Left: The Pantheon (cross section)
Right: Kimball (cross section)
The fundamental challenge of a concrete vault is to construct a system thick enough to span yet not too heavy to collapse. By the time of the construction of Kimball, it was the development of pre-stressing and post stressing concrete with steel reinforcement cables that allowed for spans with thinner concrete. Kommendant was a leading practitioner in this field, and for Kimball, he was proposing four inch thick concrete vaults with pre-stressed catenary cables.
The gravitational aspect of the cycloid is significant. Light seems to follow the same gravitational rules as the cycloid, resulting a diaphanous, silver-pewter halo above the galleries, bringing out the true colors of the paintings and creating soft shadows in the works of sculpture. During our time in the galleries we did not see a single light bulb aimed at any artwork.
Kahn was a mystic. He operated outside the more dogmatic rules of mid-century architecture. In suggesting what a building wanted to be, Kahn was engaging with the building as a being in an ontological way. This idea stood in stark contrast to his contemporaries, for example le Corbusier's idea of the house as a "machine for living," or Frank Lloyd Wright's "organic," agrarian architecture, or the Bauhaus emigres, Mies van der Rohe or Walter Gropius, whose work stressed industrial production.
"When you have all the answers about a building before you start building it, your answers are not true. The building gives you answers as it grows and becomes itself."
