What is the best known structural steel framed building?

• A. Burj Khalifa
• B. Willis Tower
• C. Empire State Building
• D. Sydney Opera House

Answer: (C)

Structural steel framing provides a skeleton of columns and beams in steel that carries vertical loads and wind, allowing the exterior walls to be lighter and non-loadbearing. The Empire State Building, completed in 1931, became the most recognized example of this approach, proving that a tall skyscraper could rise quickly and economically with a steel frame behind a masonry skin. Its iconic status—cemented by decades of culture and media—made it the defining symbol of early steel-frame construction. Other options rely on different structural systems or lack that broad cultural recognition: the Burj Khalifa uses a reinforced concrete core and tubular forms rather than a traditional steel frame; the Willis Tower uses a framed-tube system but isn’t as globally emblematic; the Sydney Opera House is driven by concrete shells with separate steel components, not a steel-framed skyscraper.