It was capped with two radio and television broadcast antennae. As Sears proceeded to provide optimistic expansion estimates, the tower’s intended floor count swiftly grew into the hundreds, exceeding the elevation of the World Trade Center. The architects designed a structure with vast floors in the bottom portion of the structure and increasingly tapered floors in a sequence of setbacks to give the Willis Tower its characteristic appearance. To be appealing to potential renters, the floor sections had to be constructed with a smaller layout and higher window-space-to-floor-space ratios. As Sears anticipated future expansion and hence additional staff, they opted to concentrate their first occupancy on housing its merchandising group, leasing out the vacant space to other businesses until more space was required.Ĭonstruction of the Sears Tower (now Willis Tower) in Chicago, Illinois Steveboerger, derivative work Lämpel, CC BY-SA 3.0, via Wikimedia Commons The framework was wrapped in aluminum, while the remainder of the structure was encased with bronze-tinted panels, allowing the tower to get enough natural sunlight and panoramas from every outside wall.Īntennas for local television and radio transmissions cap the tower at its highest point. In addition, the construction method saved up to 10 million dollars in steel expenses. The method would have a significant impact on skyscraper design and it has since been employed in the majority of skyscrapers, such as the current highest skyscraper, the Burj Khalifa. It was considered to be both technically and financially efficient: at 1,400 feet, it offered more office space and was elevated higher than the Empire State Building, all while costing significantly less. The Sears Tower in Chicago was the first building to utilize this novel design. Khan invented the “bundled-tube” design, and these nine tubes created the skyscraper’s core framework.Īs the building rose in elevation, this approach ensured big open offices on the lower floors with unimpeded city views. The varied heights allow the structure to step back, fulfilling setback restrictions and generating the building’s famous staggering appearance. The architects designed a superstructure made up of nine interconnected tubes of varied heights separated into squares that function as distinct structures connected together as one. After consulting with municipal, state, and federal authorities, the company presented Sears with two potential choices: a two-block region bordered by Jackson Boulevard, Franklin Street, Wacker Drive, and Adams Street, or the Goose Island area. Sears ordered its advisors to submit a recommendation for a location. Sears management wanted to concentrate the thousands of personnel spread over the Chicago metro into a single location. With over 350,000 workers, Sears was considered the world’s biggest retailer in 1969. Highsmith, Public domain, via Wikimedia Commons

The Willis Tower (previously Sears Tower) in Chicago, Illinois Carol M. The Willis Tower’s height is recorded as being just over 1,400 feet high and comprises 108 levels in total. Additional office space was also required in the plan to accommodate the company’s expected growth. Skidmore, Owings & Merrill was commissioned by Sears to create an office tower that would accommodate its headquarters as well as the various offices they had distributed around Chicago in one structure. The Willis Tower, which soars over the windswept metropolis of Chicago, was once the highest skyscraper in the world when it was completed in 1973. 1.1.1 Law Suits Filed During Construction.

Building formerly called sears tower