Fazlur KhanEdit

Fazlur Rahman Khan was a transformative figure in modern structural engineering, whose work at Skidmore, Owings & Merrill helped redefine the possibilities of urban skylines. As a pioneering advocate of tube-based structural systems, he turned skyscraper design into a disciplined balance of wind engineering, efficiency, and iconic form. His most famous projects in Chicago—most notably the Sears Tower (now the Willis Tower) and the John Hancock Center—embodied a philosophy that private sector ingenuity could drive urban renewal, productivity, and economic growth through taller, more efficient buildings. Khan’s influence extends beyond a single city; his ideas reshaped tall-building practice around the world and set a standard for how density and progress could be achieved in dense urban cores.

Early life and education

Khan was born in the late 1920s in a region that would become part of modern Bangladesh. He trained as a civil engineer in his home region before pursuing graduate study in the United States. His subsequent work and life in Chicago connected him with the country’s leading architectural engineers of the era. He joined the Chicago-based firm Skidmore, Owings & Merrill (SOM), where he would develop the structural concepts that defined an era of tall-building design.

Career and innovations

At SOM, Khan championed the tubular frame approach as a way to achieve high stiffness, wind resistance, and economical use of material in tall structures. The key idea was to wrap the building in a system of closely spaced, interconnected tubes that work together to resist lateral loads, allowing for slender profiles and greater usable space.

Bundled-tube design: Khan’s most celebrated contribution is the concept of a bundled-tube system, in which a collection of load-bearing tubes is grouped to act as a single, stiff entity. This approach dramatically increases height potential while controlling material costs and construction complexity. The Sears Tower’s distinctive nine-tube bundle is the most famous application, but the method influenced many subsequent skyscrapers and remains a foundational principle in tall-building practice. See Bundled-tube design for the technical articulation of this concept.
Wind and structural optimization: Khan’s work integrated wind tunnel testing, aerodynamic consideration, and architectural expression, showing how structural efficiency could align with urban aesthetics. He helped codify methods to translate wind forces into practical, economical solutions for very tall buildings.

Khan’s design work with Skidmore, Owings & Merrill contributed to a broader shift in American skyscraper practice, reinforcing the notion that private firms could deliver both architectural ambition and engineering rigor in service of urban economic goals. The era he helped shape contributed to a skyline that was not only taller but also more productive, with efficient floor plates and improved construction sequencing.

Notable projects

Sears Tower / Willis Tower (Chicago): Completed in the early 1970s, this building rose to a height that made it the world’s tallest at the time. It employed the bundled-tube concept to achieve extraordinary height and stiffness, consolidating Chicago’s status as a center of tall-building innovation. See Sears Tower and Willis Tower.
John Hancock Center (875 North Michigan Avenue, Chicago): Finished in 1969, this 100-story tower is known for its bold exterior bracing and distinctive silhouette. The building demonstrates Khan’s willingness to let structural elements become architectural statements, while still delivering efficient space use. See John Hancock Center.
Other influential work: Khan’s broader portfolio with SOM helped popularize tall-building methods and wind-conscious design, influencing projects beyond Chicago and contributing to the global expansion of skyscrapers in dense urban settings. See Skidmore, Owings & Merrill.

Design philosophy and impact

Khan’s approach bridged practical engineering with the economic realities of urban development. By increasing floor plate efficiency and reducing the amount of material needed for lateral strength, his systems lowered the cost per square foot of usable space for very tall buildings. This combination of performance and cost-effectiveness made tall towers more viable for business districts seeking to concentrate commerce, housing, and transportation access in compact urban footprints. The result was a catalyst for downtown revitalization and private investment in city cores.

Critics and proponents alike debated tall-building strategy during Khan’s era. Supporters pointed to urban densification, improved land-use efficiency, and the successful integration of wind engineering into everyday construction. Critics sometimes argued that visually bold, high-rise towers could dominate city skylines or influence neighborhood character in ways that favored centralized economic activity over dispersed, human-scale urban planning. In the broader market-driven urban renewal context of the time, Khan’s work is often cited as an exemplar of how private-sector engineering excellence could deliver powerful economic and social benefits by expanding the usable footprint of urban centers.

Legacy

Khan’s career left a lasting imprint on structural engineering and skyscraper design. The tubular concept he helped pioneer enabled a generation of taller, more efficient buildings and solidified Chicago’s reputation as a laboratory for tall-building innovation. His ideas influenced not only the construction of the Willis Tower and the John Hancock Center but also the broader practice of high-rise design around the world, shaping how firms approach wind loads, floor efficiency, and the integration of structural systems with architectural form. Khan’s legacy is carried on by the engineers and architects who study his methods, by the ongoing work of Skidmore, Owings & Merrill, and by the continued exploration of how dense urban space can be created and sustained through thoughtful engineering.