Exterior Rythm

The Kimbell Art Museum, designed by Louis I. Kahn in 1972, is widely regarded as one of the outstanding architectural achievements of the modern era. Kahn created a building in which “light is the theme.” Natural light enters through narrow plexiglass skylights along the top of cycloid barrel vaults. It is diffused by wing-shaped pierced-aluminum reflectors that hang below, giving a silvery gleam to the smooth concrete of the vault surfaces and providing a perfect, subtly fluctuating illumination for the works of art.

Kimbell Art Museum Technical Information

  • Architects: Louis Kahn
  • Location: Fort Worth, Texas, United States
  • Material: Concrete, Plexiglass, Aluminium
  • Type: Museum
  • Structural Engineer: August E. Komendant
  • Mechanical/Electrical Engineer: Cowan, Love & Jackson, Inc.
  • Landscape Architect: George E. Patton, Inc.
  • Project Architect: Marshall Meyers
  • Project years: 1966 – 1972
  • Drawings: © Louis Kahn Architects, ETH Zurich University
  • Photographs: © Richard Anderson, © Nic Lehoux

The museum has as many moods as there are moments in time, and never… will there be a single day like the other.

– Louis Kahn

Kimbell Art Museum Photographs

© Nic Lehoux

Entrance in the Kimbell Art Museum

© Ezra Stoller

Stair in the Kimbell Art Museum

© Ezra Stoller

Travertine Walls in the Kimbell Museum

© Richard Anderson

Light inside the Kimbell Museum by Louis Kahn

© Richard Anderson

Interior of the museum by Louis Kahn

© Richard Anderson

Stairs in the Kimbell Museum

Richard Anderson

Light entrance in the Kimbell Museum

Richard Anderson

Text from the Kimbell Art Museum foundation

The building was commissioned in 1966 by the Board of Directors of the Kimbell Art Foundation, working closely with Kimbell’s first director, Richard F. (Ric) Brown, who enthusiastically supported his appointment.

Light

The main (west) facade of the building consists of three 100-foot bays, each fronted by an open, barrel-vaulted portico, with the central, entrance bay recessed and glazed. The porches express on the exterior the light-filled vaulted spaces that are the defining feature of the interior, which are five deep behind each of the side porticos and three deep behind the central one. Additionally, three courtyards punctuate the interior space. Though thoroughly modern in its lack of ornament or revivalist detail, the building suggests the grand arches and vaults of Roman architecture, a source of inspiration that Kahn himself acknowledged. The principal materials are concrete, travertine, and white oak.

Structure
Section Original Drawing

Credit: Louis Kahn

One of the architect’s fundamental tasks is formulating the structure, or arrangement of forms, that the building will assume. Each architect has an individual approach to developing that initial concept. Kahn is often quoted as first asking, “What does this building want to be?” He believed that the essence of the structure started with the room, and thinking about how that space would be used and how it should feel. From that point, the building evolved as a “family of rooms” with a simple plan based on classical proportions, repetition, and variation.

In the case of the Kimbell, director Richard Brown provided an initial list of important considerations for generating ideas for the structure. In that “Pre-Architectural Program,” Brown explicitly stated that “natural light should play a vital part in illumination.” This stipulation, along with Kahn’s keen interest in the use of natural light, resulted in Kahn’s early concept of a room with a vaulted ceiling that would allow natural light to enter the space from above. The vault also appealed to Kahn’s admiration for ancient structures—from Roman arches and storage warehouses to Egyptian granaries.

Kahn determined the exact shape of the vault through his collaboration with a structural engineer, Dr. August E. Komendant. As opposed to semicircular vaults, the cycloid vault has gently rising sides that give the impression of monumentality without overpowering the visitor. By mathematical definition, the cycloid is the curve traced by a point on the circumference of a circle that rolls on a straight line without slipping. This geometric form is capable of supporting its weight and has been likened to an eggshell for its ability to withstand heavy pressure. At the Kimbell, the weight for each vault is directed through four corner columns measuring two square feet. Unlike classical precedents, Kahn’s vaults are interrupted at the top by skylights and require concrete struts that connect the shells at ten-foot intervals. Additionally, Kahn and his engineers placed long steel cables inside along the length of each vault. After the concrete had hardened for a week, hydraulic jacks were used to tighten the cables to create a system of post-tensioning that distributes and supports the weight of the roof—similar to a suspension bridge.

Like classical buildings (such as the Parthenon), Kimbell’s structure is based on a consistent mathematical model. The basic plan is composed of sixteen cycloid vaults (100 x 20 feet) that are arranged in three parallel units of six, four, and six in the Kimbell. Other elements are based on a ratio of 20 to 10. For example, on the floor, wood sections measure 20 feet, and travertine sections are 10 feet. The building is based on these “rules” of logic, enabling the visitor to follow and “read” the structure easily.

Although the structure is based on a simple plan of unadorned, repeated forms, Kahn also introduced variations on those primary forms and “themes.” The porticos at the Kimbell’s entrance on the west side of the building first introduce the vault to the approaching visitor and demonstrate the form’s versatility. Within the Museum, visitors see that vaults cover the galleries, an auditorium, and the Buffet Restaurant. Kahn also varied the size of the courtyards. The North courtyard is 40 square feet, while the South patio is 20 square feet.

The “rooms” were designed to relate to the visitor on an intimate level to enhance their experience of the artworks on view. Space was designed to be as flexible as possible within the confines of the vaulted areas. Moveable walls can be attached to the soffits (the underside joint between arches) in various configurations to best suit the Museum’s display needs.

Materials

Aerial View Construction

To make a structure that will stand the test of time, architects choose materials that are strong and durable, as well as pleasing to the eye. Kahn preferred simple forms and natural materials. To achieve a sense of serenity and elegance in the Kimbell, Kahn selected materials that complemented each other in tone and surface: travertine, concrete, white oak, metal, and glass. Simple and unadorned, each of these materials shows its innate character by its variation of texture.

Concrete, according to Kahn, was “a noble material if used nobly.” Revolutionizing the modern use of materials, Kahn viewed concrete as both an aesthetic and structural choice. In Kimbell’s galleries, concrete vaults shimmer with light to create a subtle luminosity that Kahn compared to a “silvery powdered moth’s wing.” Reinforced concrete also supports the weight of the structure in the form of vaults, walls, and piers. Creating the right look to the concrete was a matter of serious importance to Kahn, who went to great lengths to select the proper color (soft gray with lavender tones) determined by the mixture of sand and cement. Numerous wall tests were poured and allowed to cure in the Texas sun until they found the right surface qualities and the perfect match for the soft tones of the travertine. Kahn believed that buildings should tell the story of how they were made and that incidents of the construction process should be left as a visual record. Accordingly, when they occurred, marks from plywood mold forms, bits of rubber, and air pockets remain for all to see (although the workmen practiced attaining perfection).

Travertine, on the other hand, acts only as “in-fill” material. Kahn even called it wallpaper. (Glass and wood are also non-weight-bearing materials in the Museum.) The travertine (a type of colored limestone) used for the Kimbell was imported from Tivoli, near Rome, Italy. This material is riddled with irregularly shaped holes left by gases and pieces of vegetation trapped in hardened layers of calcium carbonate. Despite its “Swiss-cheese” texture, travertine is a durable material and has been used since antiquity for countless buildings. Kahn was deeply influenced by monuments and ancient ruins that he studied as a student and sketched on his travels through Italy, Greece, and Egypt. In his buildings, Kahn used such materials as travertine to emulate the timeless and monolithic qualities he so admired in those ancient structures. Over one million pounds of travertine sheath much of the Kimbell’s interior and exterior walls, gallery floors, porches, and stairs. These thin, rough-hewn pre-cut slabs (5/8 inches thick) were shipped from Italy in 17 boatloads over nine months. Fissures and openings were not filled. Every attempt was made to retain the material’s natural appearance.

Lead was selected for the roof cover for its color, dull sheen, and discreet, natural appearance. Because this soft metal ages quickly, Kahn believed that it would look consistent with the travertine and concrete. In keeping with his palette of warm and cold tonal harmonies, Kahn also selected white oak for the gallery floors, doors, and cabinetry; anodized aluminum (a light-weight metal noted for its high reflectivity that has been covered with a protective oxide coating) for the soffits and reflectors; and mill-finished steel for windows and door frames, elevators, and handrails, as well as in the kitchen, conservation studio, and darkroom. Kimbell’s uniquely shaped handrails are made of folded metal, because Kahn preferred emphasizing the sheet quality of the material instead of pretending that it was worked like a solid material, such as wood.

Kimbell Art Museum Site Plan and Floor Plan

Site Plan

Floor Plan

Credit: Louis Kahn

Louis Kahn’s Kimbell Art Museum Image Gallery

Other works from Louis Kahn