The revolutionary skyscrapers of Fazlur Khan

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Gazing across the horizon from the top floor of a 100-story building is like touching the sky. But who would stand 1,000 feet in the air without the firm assurance that the structure beneath was securely fastened to the ground?

“I put myself in the place of a whole building, feeling every part. In my mind I visualize the stresses and twisting a building undergoes.”

We owe that certainty to Fazlur Khan, whose revolutionary designs resulted in soaring skyscrapers that are safe, architecturally innovative, and environmentally-friendly. Khan saw that a building’s exterior wall, or “skin,” could effectively provide the structure of the building, obviating the need for an additional, rigid steel-frame support. As the “father of tubular design” for high-rises, he created tubular steel systems that significantly increased the stability and strength of buildings, which in turn allowed for their increased height. Khan’s engineering methods also reduced the amount of steel and other materials used in construction, making them more efficient and less wasteful.

As his daughter, Yasmin Byron, explained: “At the time my father started working as a structural engineer at SOM [Skidmore, Owings and Merrill], in the 1950s, engineers and developers accepted the fact that a tall building was far more expensive, per square foot of floor area, to build than a relatively short, low-rise, building. This was because all buildings basically followed the structural plan of a two-story building, adjusting for greater height by using stronger beams and columns and walls.”

Willis Tower in Chicago (Wikipedia)

Willis Tower in Chicago (Wikipedia)

But the conventional design of beams and columns could not adequately resist lateral loads, which are horizontal forces such as high winds and gravitational movement during earthquakes. Prior to Khan’s innovations, Byron noted, “taller buildings became very expensive as engineers increased the bulk of the structural members. What my father achieved with his new structural systems was the ability to design strong and stiff tall buildings that naturally resist wind load as a result of their structural form … [He] developed forms for building design by thinking of a building as a whole entity and imagining how it would behave in wind. Engineers had not taken this approach before.”

Khan had the extraordinary ability to imagine himself as a building so he could envision how it would respond to diverse structural and environmental conditions. He once described the process: “I put myself in the place of a whole building, feeling every part. In my mind I visualize the stresses and twisting a building undergoes.”

Khan’s designs included the “framed tube,” a three dimensional structure consisting of at least three frames, joined together to form a vertical tubular system that can resist lateral forces. The innovative tubes also preclude the need for multiple interior columns, resulting in increased floor space inside a building.

Another ground-breaking design, the “bundle tube,” was a versatile concept that enabled the construction of buildings in unconventional shapes, replacing the standard boxy forms. Khan used bundle tubes for the (Willis) Sears Tower, the world’s tallest building until 1996, and for One Magnificent Mile in Chicago.

“[My father] credited his father with teaching him that it was his responsibility as a good person to use his education and career to help people.”

He also adapted a “trussed” tubular system for the Onterie Center and John Hancock buildings. Their characteristic “X-bracing” pattern inaugurated the structural expressionist style, and directly incorporated artistic display within the support system.

Khan’s creative mind, coupled with his training as an architect and engineer, allowed him to envision aesthetic concepts and structural configurations in a novel way. Byron explains that he viewed his work as “constructive art.” Not only were his designs practical, but they also took into account the well-being of the people who used them. “Previously, a developer might opt, for cost reasons, for a low-rise building that filled the property footprint,” Byron elaborated. “But with the introduction of efficient structural systems for tall buildings, a developer could consider a taller building that left open space at the ground level for a plaza.”

One Magnificent Mile in Chicago (Wikimedia)

One Magnificent Mile in Chicago (Wikimedia)

Khan’s altruistic sensibilities were rooted in his early experiences in Bangladesh, where he was born in 1929. Although he became a naturalized U.S. citizen in 1967 and was enormously successful, Khan never forgot the plight of less fortunate people. For instance, when the Pakistani military government attacked East Pakistan in the early 1970s, Khan founded and headed the Bangladesh Emergency Welfare Appeal, a major relief fund to help the suffering inhabitants in the region. He was also a committed patron of the arts.

“My father was always conscious that many people have barely enough to eat and minimal shelter,” Byron said.  “I believe this strengthened his desire to reduce material waste (which he did in building design). However, he received a good education in Bengal and was well-prepared for his doctoral studies when a Fulbright scholarship brought him to the U.S. He credited his father with teaching him that it was his responsibility as a good person to use his education and career to help people.”

By the time Khan died in 1982, he had transformed modern construction with innovative, towering buildings that were safe, efficient, and aesthetically pleasing. He combined architectural and engineering achievement with humanitarian compassion, embodying his own definition of an exemplary technical man:

“The technical man must not be lost in his own technology. He must be able to appreciate life; and life is art, drama, music, and most importantly, people.”

Contact Mary McCleary at [email protected].