Structure meets architecture

    Habitat 67 features 158 apartments placed on top of each other and set back, like a pyramid. Photo: Timothy Hursley

    August Komendant may not be a name that triggers immediate recall, but his signature is all over some of the monuments of the 20th century. He was a structural engineer who immigrated to the United States from Europe and brought advanced concrete methods and analysis with him. If that was all he did, he would be a distinguished member of the engineering community, but he went much further. It is fair to say that if he had not been at Louis Kahn’s side, the well-known architect might have slipped beneath the waves unnoticed by the public and architects. Louis Kahn was a prominent architect before he met Komendant, but their collaboration transformed his reputation into that of a genius.

    Komendant was born in Estonia in 1906 and received his engineering degree at the technical institute in Dresden, Germany. His early engineering included a stint working for General Patton, examining buildings and bridges at the end of World War II. He later said he acquired much knowledge from those inspections that went beyond accepted theory.

    His first association with Kahn was with the Medical Research Laboratory in Philadelphia in 1957.

    Komendant was one of the first engineers to use precast and post-stressing in a multistory frame building by creating one of the first entirely precast buildings in the United States. Even the columns were post-tensioned. In this building he designed a structural system based on the Vierendeel truss, which had been used in Europe but was new to America. He designed a two-way structural system in which there are two long Vierendeel trusses in one direction and smaller Vierendeel trusses connected with post-tensioning in the other direction. During this period, architects wanted to have the structure of the building clearly visible. This building does this in an interesting and elegant way by exposing the trusses at a corner at the entrance. With that orientation, one sees the trusses coming together.

    Komendant often went way beyond the normal role of an engineer. If he saw something that didn’t look right, especially if it looked structurally wrong, he would bring it to Kahn’s attention. Kahn didn’t always appreciate the often unsolicited advice but usually accepted it.

    In 1959, Komendant helped with both the engineering and design of the First Unitarian Church in Rochester, N.Y. Kahn had delineated the spaces but could not figure out what to do with the roof. He had proposed large beams going across with slabs on top, but Komedant pointed out that the beams might instill fear in the congregation rather than comfort. Komendant proposed a roof using two-way folded plates. Kahn was impressed and asked Komendant to come up with some variations of this proposal. Komendant came up with nine ways to do it. The plates would not only furnish a sturdy structural system but also create an amazing ceiling in which light came in through the light wells at the four corners and echoed the vaults of the great cathedrals.

    The Salk Institute for Biological Studies was the next big project for Kahn, and Komendant was right at his side from the start. Post-tensioned concrete was just getting started in the United States. Builders and building inspectors were new to this type of structure, but Komendant was able to shepherd his plans through building officials with a mix of grace and bulletproof analysis to get the permit.

    In 1966, Komendant collaborated with Moshe Safdie to create an incredible apartment complex in Montreal. Safdie was only 28 years old and Habitat 67 ( was his first building. The apartment complex, an astounding sight and a structural marvel, was built entirely out of prefabricated components.

    Going into the design phase of Habitat, Safdie was unsure about the structure of the building. There were different ways to accomplish prefab, including building a frame and inserting apartment modules. Safdie thought having each module contribute to the overall structure was the way to go and asked Komendant about it. After studying the plans, Komendant declared, “Yes it can be done.” Safdie later referred to that as “the famous, ‘Yes it can be done’” because engineers who followed told him that it couldn’t be done. Safdie also said unequivocally that without Komendant, Habitat wouldn’t have been built.

    Habitat 67 features 158 apartments placed on top of each other and set back, like a pyramid. But this could hardly be called an ordinary array because some apartments are moved forward, some back, some up, some down, and a few straddle the space between two apartments. Safdie wanted this arrangement so that each apartment could have an outdoor space, which was actually on top of the module below. The design was unique but the brave part was making each module an inherent part of the structure.

    Although the apartments varied in size and layout, they were all based out of a single box whose dimensions were 17-1/2 feet by 38-1/2 feet by 10-1/2 feet. All were load bearing and connected to each other with post-tensioning. When completed, the building was hailed as an important milestone and was a big attraction at the Expo67 world fair.

    In 1966, Komendant collaborated with Moshe Safdie to create Habitat 67, built entirely out of prefabricated components. Photo: Jerry Spearman

    While Komendant was working on Habitat 67, Kahn was given the commission for a factory by the Olivetti Company and soon after he engaged Komendant to help him with the job. The Olivetti-Underwood factory in Harrisburg Pa., a structural and architectural success, was delivered in a dramatic fashion.

    Early in 1967, Komendant and Kahn’s offices made preliminary studies of the layout, structure, and parking. Kahn wanted to design a showplace but couldn’t come up with anything and for months the commission languished. Finally, Kahn, in a fit of desperation, called Komendant. Olivetti had scheduled a meeting the next day and was expecting Kahn to show them the final design. But Kahn had nothing! He begged Komendant to bail him out of this tremendous jam, incredibly, less than 24 hours before the meeting.

    Komendant told him there was no way to create something in that short period of time and to reschedule to at least the next day. Olivetti was impatient and irritated because they needed that factory online soon and Kahn was apparently dawdling.

    Komendant had been working on the project all along and had mostly completed one proposal. But at the last minute he had another idea. He worked through the night and the next day and came up with a dramatic alternative that was architecturally and structurally innovative. Company officers, including Olivetti himself, were impressed and asked Kahn and Komendant to proceed with the working drawings.

    Structurally, the design was economical and daring. The factory is covered by a series of inverted mushrooms, each having a diameter of 59 feet. At the corners are skylights. The upper rim of the inverted mushrooms is bolstered by prestressing.

    Safdie described Komendant as “extremely dogmatic, stubborn, and autocratic,” but he could also relax. In his book, 18 Years with Architect Louis Kahn, Komendant repeatedly recalled good times “downing a few.” He delighted in telling jokes only an engineer would relate to.

    When theorizing about the best space for a church, Kahn came to the conclusion that light and silence were crucial. Then he asked, “What is silence?” Komendant answered, “Zero density of sound.”

    Komendant’s office was his home and his staff numbered only two. Although computers weren’t as prevalent as they are now, they were being used in engineering, but Komendant did his own calculations and his own drawings.

    August Komendant in the 1980s standing in front of Habitat 67.Photo courtesy of Merike Komendant

    The Kimball Art Museum in Ft. Worth, Texas, is a structural paradox. To the casual observer it is a series of barrel vaults. Barrel vaults have been around since ancient Rome and this building wouldn’t have aroused much notice. However, beneath the surface are some striking discrepancies.

    Kahn’s first draft design was a series of barrel vaults, but the museum director objected to the high ceilings. The director saw a cycloid in a book on shell structures, which was almost like a flattened arch. However, it is derived from a completely different source. A cycloid is a curve that is plotted from the points of a rolling circle.

    But that is just the first aspect of the paradox. For a barrel vault or even a flattened arch to work, it must be supported on both sides along its length. The forces are transmitted from the ridge of the roof to the eaves and then to the ground. However, in the Kimball Art Museum there are vast stretches of open space directly beneath the edge of the vaults.

    How can this be? It doesn't make structural sense!

    There is one other aspect of this building that also doesn’t make structural sense. Normally in a barrel vault, the greatest stress would be at the ridge. However, in the Kimball Art Museum there is a skylight at that exact location. At this point, the original engineers on the project requested Komendant be called in to help.

    The roof structure of the Kimball Art Museum doesn’t work as a vault but as a beam. Komendant designed a beam section that is half of one vault and half of the adjacent vault. When two of them are adjacent to each other they form a vault. By cleverly reinterpreting sound engineering principles, Komendant was able to create a 20th century masterpiece.

    Komendant was a gifted engineer who looked at structure not just as support of the building but also as architecture. He was able to turn architects’ abstract ideas into monuments. In 1978 he was awarded the AIA allied professions medal. He also wrote four books, three of which were engineering books, and was 85 years old when he died in 1992.

    Rick Wilmath has worked in construction for the last 30 years. He is now owner of Rubia Roofing (