Fazlur Rahman Khan: The Dhaka Engineer Who Reinvented the Skyscraper

Fazlur Rahman Khan was born in Dhaka in 1929, when the skyscraper still belonged to New York. By the time he died in Jeddah in 1982, at only fifty-two, the tallest building in the world stood in Chicago — and it stood there because of structural ideas he had invented. Khan, a Bengali Muslim engineer who became an American citizen without ceasing to be a son of Dhaka, changed the basic grammar of tall buildings. Where earlier towers had hidden their strength in a dense forest of interior columns and bracing, Khan taught the building to carry its loads in its own skin: first as a framed tube, then as a braced tube of giant diagonal crosses, then as a bundle of tubes tied together like a cluster of reeds. The John Hancock Center and the Sears Tower — today the Willis Tower — made him, in Britannica's phrase, the "father of tubular designs". His last great work was not a tower at all but a tent of fabric and steel raised for the pilgrims of the Hajj. Few engineers have reshaped two skylines as different as Chicago's and Jeddah's; none began further from either than a schoolboy in Dhaka.

A Dhaka Childhood and an Engineer's Training

Khan was born on 3 April 1929 in Dhaka, then a city of British India, into a Bengali Muslim family rooted in the village of Bhandarikandi in the Faridpur region. His father, Abdur Rahman Khan, was a mathematics teacher and textbook writer who rose to become a senior official in Bengal's education department and, after retirement, principal of Jagannath College in Dhaka. It was a household where education was not an ornament but a profession, and the young Khan grew up around books, examinations and the expectation that learning was a form of service. Biographical accounts recall a grandfather, himself an educationist and author of mathematics textbooks, setting the boy extra problems and encouraging him to look at every question from more than one side — a habit of mind that would later define his engineering.

He began his engineering studies at Bengal Engineering College at Shibpur, across the river from Calcutta, but history intervened. The Partition of India in 1947 tore Bengal in two amid terrible violence, and Khan was forced to abandon his studies in his final year. He crossed into the new East Pakistan and completed his Bachelor of Civil Engineering at Ahsanullah Engineering College in Dhaka — the institution that is now the Bangladesh University of Engineering and Technology — graduating in 1950 at the head of his class. He worked briefly as an assistant engineer and taught in Dhaka, but his ambitions already pointed further.

In 1952 a Fulbright Scholarship and a Pakistan government scholarship carried him to the University of Illinois at Urbana-Champaign. What followed was one of the most compressed graduate educations in the history of American engineering: in about three years Khan earned a master's degree in civil engineering, a second master's in theoretical and applied mechanics, and a doctorate in structural engineering, completed in 1955. His doctoral thesis, on the design criteria of prestressed concrete beams, sounds narrow; in fact it trained him to think about how materials, geometry and economy interact — the exact triangle on which his later career would turn. America was entering its great age of corporate towers. Khan was ready for it.

SOM and the Tubular Idea

Khan joined the Chicago office of Skidmore, Owings & Merrill — SOM — in 1955, straight from his doctorate, and began on bridges and prestressed concrete. The stay was interrupted: in 1957 he returned to Pakistan to fulfil the obligations of his scholarships, tried private design work in Dhaka, and then took a senior post as an executive engineer with the Karachi Development Authority. The job frustrated him. Administration kept him from the drawing board, and in 1960 he returned to SOM in Chicago on a permanent basis. He never left again. He became a participating associate in 1961, a partner in 1966 and a general partner in 1970, and from 1961 he also taught structures to architecture students at the Illinois Institute of Technology. In 1967 he became a citizen of the United States.

At SOM, Khan's crucial partnership was with the architect Bruce Graham — Graham shaping the architecture, Khan inventing the structures that made Graham's ambitions buildable. Their shared problem was economic as much as technical. By the early 1960s the conventional wisdom held that very tall buildings cost more per square foot the higher they rose, because ever more steel had to be sacrificed to resisting wind. Khan's answer began with a simple physical intuition, which he liked to explain with the example of a bamboo stalk: a hollow tube is nature's most efficient answer to bending. If a building's exterior could be made to behave as one vertical tube — its perimeter columns spaced closely and tied together by deep beams at every floor — then the whole skin of the tower would resist the wind, and the interior could be left comparatively free.

The proof came in an unglamorous building. The DeWitt-Chestnut Apartments in Chicago, completed in 1965, was the first framed-tube high-rise: a residential tower whose closely spaced concrete perimeter columns and spandrels formed a rigid exterior tube that absorbed all the wind loads. In the same years the Brunswick Building, also in Chicago and completed in 1965, tested his shear-wall frame interaction system, in which a concrete core and the outer frame work together — a tube within a tube — becoming the tallest reinforced-concrete structure of its time. One Shell Plaza in Houston, completed in 1971, carried the tube-in-tube idea further, in lightweight concrete. Khan was also pushing the tools of the profession: at his urging SOM installed an IBM 1620 computer in 1963, making the firm a pioneer in the computer analysis of structures. The tube was not one invention but a family of them, and the family was about to grow very tall.

Hancock and Sears: Rewriting the Skyscraper

The John Hancock Center, completed in 1969 and known today by its address, 875 North Michigan Avenue, turned Khan's idea into an icon. Graham and Khan proposed a single tapered tower of 100 stories, mixing offices, apartments, shops and parking in one of the world's first mixed-use skyscrapers. A tapered box, however, needs its structure expressed boldly, and Khan supplied the trussed tube: enormous X-braces marching up all four faces of the building, carrying wind loads down the exterior and doing the work that a conventional tower hides inside. The braces were not decoration applied afterwards; they were the structure, and the structure was the architecture. The building's famous economy — a 100-story tower for roughly the structure budget of a much shorter one — announced that the old rule, taller means ruinously expensive, was dead.

The Sears Tower, completed in 1973 and now the Willis Tower, went further. Sears, Roebuck and Co. needed huge floors for its own headquarters and smaller floors for tenants above. Khan's response was the bundled tube: nine square tubes, each 75 feet by 75 feet, locked together at the base into a single cellular structure of about 1,450 feet. Because the nine tubes share their loads, each can simply stop where it is no longer needed — some end at the fiftieth floor, others higher — and so the tower's distinctive stepped silhouette is not a stylistic gesture but a diagram of its own structure. The bundled tube used steel with startling frugality, by common account around 33 pounds per square foot, comparable to a conventional building forty stories shorter. On completion the Sears Tower became the tallest building in the world, a title it kept for about a quarter of a century.

Together, the two Chicago towers settled the argument of Khan's career. Height was no longer a brute contest of material; it was a problem of geometry, solvable by arranging ordinary columns and beams into systems whose whole was far stronger than their sum. Every supertall building designed since has begun from the menu of systems — framed, trussed, bundled and composite tubes — that Khan laid out in little more than a decade.

The Later Work and the Hajj Terminal

Khan's later career ranged well beyond Chicago, though the towers continued: One Magnificent Mile in Chicago, the composite-tube One Shell Square in New Orleans, and the Onterie Center in Chicago, completed after his death with its structure still speaking his language. With Graham he also designed the Baxter Travenol Laboratories in Illinois, where a roof is suspended from cables — a reminder that his imagination worked horizontally as happily as vertically. In Jeddah he engineered King Abdulaziz University. But the work that best shows the range of the man is the Hajj Terminal at King Abdulaziz International Airport, completed in 1981, in whose design he worked with the architect Gordon Bunshaft.

The problem was unlike any skyscraper. For a few weeks each year, the airport receives the pilgrims of the Hajj, who must be sheltered — sometimes for many hours — in the fierce Jeddah heat while they wait for transport to Makkah and Madinah. Khan and his colleagues answered with the form of the Bedouin tent, executed at a scale no tent had ever reached: a vast, open-sided roof of Teflon-coated fiberglass fabric, its 210 semi-conical units gathered into ten modules and held by steel pylons 45 metres high. The fabric admits a softened daylight, sheds the desert heat and lets the space beneath breathe naturally. The terminal can shelter tens of thousands of pilgrims at a time — as many as 80,000 in its departing configuration — and on completion it was the largest cable-stayed, fabric-roofed structure in the world. In 1983 it received the Aga Khan Award for Architecture, which honoured the roofing system itself. It remains, four decades on, the building where Khan's engineering and his inheritance meet most visibly: a structure of advanced tensile technology shaped entirely by the needs, climate and dignity of Muslim pilgrims.

Faith, Philosophy and the Man

Khan's private coordinates were as distinctive as his public ones. He was a Bengali Muslim who had become an American citizen in 1967; he was also a man who loved to sing the songs of Rabindranath Tagore in Bengali, and who understood his two inheritances as one life rather than a contradiction. When Bangladesh fought its Liberation War in 1971, Khan worked from Chicago to build American public opinion and raise emergency funds for his suffering homeland, founding the Bangladesh Emergency Welfare Appeal. The engineer of the world's tallest building spent that year, in part, as an organiser for refugees he would never meet.

His philosophy of engineering was humanist before it was technical, and he stated it in words that Lehigh University and his family have preserved: "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." The sentence explains much about the buildings. Khan did not write treatises; he taught — at the Illinois Institute of Technology, in professional papers and lectures around the world — and he treated teaching as part of the work itself. His daughter Yasmin Sabina Khan, herself a structural engineer, would later write the standard account of his thought in her book Engineering Architecture: The Vision of Fazlur R. Khan. Those who worked beside him remembered a collaborator rather than a solitary genius: a man who put himself, in another of his recorded phrases, "in the place of a whole building, feeling every part", and who insisted that a structure succeeds only when it serves the people inside it. His faith, likewise, was expressed less in pronouncement than in practice — most concretely in a terminal designed so that pilgrims performing the Hajj would be received with shade, air and dignity.

Death and Legacy

Khan died of a heart attack in Jeddah on 27 March 1982, aged fifty-two, while working in the city of his last masterpiece. He was buried at Graceland Cemetery in Chicago, the city his tubes had remade. The honours that had begun in his lifetime continued after it. Engineering News-Record, which had cited him five times for service to the construction industry, had named him its Construction's Man of the Year in 1972; in 1973 he was elected to the National Academy of Engineering, the highest professional honour open to an American engineer. Northwestern University and Lehigh University gave him honorary doctorates, in 1973 and 1980. In 1999 Bangladesh awarded him its Independence Award posthumously, the country's highest civilian honour, and issued a commemorative postage stamp in his memory. Professional memory took institutional form: Lehigh endowed the Fazlur Rahman Khan Chair of Structural Engineering and Architecture — first held, from 2006, by Dan M. Frangopol — together with a distinguished lecture series in his name, while the Council on Tall Buildings and Urban Habitat named its lifetime achievement medal for him. Writers reached for the largest comparison available and called him the "Einstein of structural engineering", a nickname popularised by Richard G. Weingardt's 2011 profile of that title in STRUCTURE magazine. In 2009 President Barack Obama, speaking in Cairo, cited Khan among the American Muslims who had helped build the United States; in 2017 Google marked his birthday with a Doodle.

The deeper legacy is standing in the world's skylines. When SOM came to design the Burj Khalifa in Dubai, the world's tallest building, its engineers did not copy Khan's bundled tube — the tower uses a buttressed core, developed by Bill Baker with Adrian Smith — but SOM itself says that Khan's work continues to influence its supertalls, Burj Khalifa included. That is the correct measure of his place: not that later towers repeat his systems, but that they think in his way, drawing strength from the arrangement of the whole rather than the mass of the parts. The "premium for height" that once made tall buildings irrational has never returned.

Conclusion

Fazlur Rahman Khan's life describes an extraordinary arc: a Dhaka schoolboy displaced by Partition, a scholarship student who took three degrees in three years, a Karachi administrator who walked away from a desk job to design, and finally the general partner of SOM who redrew the skyline of Chicago and sheltered the pilgrims of Jeddah. He left Bangladesh as a young man and built his career an ocean away, yet Bangladesh runs through the story from first to last — in the education that formed him, in the cause he served in 1971, and in the Independence Award that brought his name home in 1999. The towers were the achievement; the philosophy — that the technical man must not be lost in his technology — was the man. Between the two, he remains the most consequential engineer Bangladesh has given the world.