Willis (formerly Sears) Tower. Photo © Hedrich Blessing
Willis Tower—OK, many of you still call it Sears Tower—is a beacon of civic pride for Chicagoans everywhere.
…
Structural engineer Fazlur Rahman Khan jump-started a new era in skyscraper construction with the various tube designs that, to this day, remain the foundation of modern supertall structural engineering. Khan, fresh off the triumph of his tressed tube design for the John Hancock Center, worked with Skidmore, Owings & Merrill architect Bruce Graham to design Willis Tower as nine separate buildings, or “tubes,” that all rose 50 stories.