Building of the Month - Sears Tower

Building of the Month - Sears Tower
Building of the Month
The Times Press Releases Publications Building of the Month
What building held the title of World's Tallest for 22 years?
Sears Tower
Location: Chicago, Illinois, USA
Height: 1,450 ft/442m
Stories: 110
Use: Office
Area: 4.4 million sq. Ft.
Material: Structural steel
Cladding: Bronze-tinted glass, black anodized aluminum
Completed: 1974
Architects: Skidmore, Owings, & Merrill (Bruce Graham)
Structural Engineer: Skidmore, Owings, & Merrill (Fazlur Rahman Khan)
Mechanical Engineer: Jaros, Baum, & Bolles
Developer: Sears, Roebuck, & Co.
General Contractor: Diesel Construction (now Morse Diesel Inc.)
Electrical Engineer: Jaros, Baum & Bolles, Assoc.
Erector: American Bridge Division, US Steel
Fabricator: American Bridge Division, US Steel
Interior Space Planner: Saphier, Lerner, Schindler Inc.
Rental Agent: Cushman & Wakefield Inc.
Elevator: Westinghouse Elevator
In the "windy city" of Chicago, a city of many landmarks, one structure stands far above the rest. Chicago is a city that enjoys attention for having the superlatives of biggest, busiest, or tallest.
Completed in 1974, Chicago's Sears Tower is the largest private office complex in the world. The total development contains a gross area of 4.4 million square feet with 101 acres of floor space. The daily population is approximately 16,500 people.
Sears Tower has 3.9-million-ft gross square floor area rising 109 stories or 1,468.5 feet above the Chicago city datum. It occupies a full Chicago block of approximately 129,000 square feet bounded by Wacker Drive on the west, Franklin Street on the east, Adams Street on the north, and Jackson Boulevard on the south.
From 1974-1996 Sears held the title of "world's tallest" undisputedly. Then, with the completion of the Petronas Towers in Kuala Lumpur, media attention focused on a "competition" with the Petronas Towers in Malaysia but that did not really exist. Petronas, when topped out in March, 1996 at 452m (1483 ft) exceeded Sears--at 442m (1450 ft). The height criteria: architectural or structural top (exclusive of broadcast antennas) was unchanged.
In 1996, height criteria were added: height to the highest occupied floor, height to the top of the roof, and height to the top of the antenna. Sears olds the record for floor and for roof, World Trade Center for antenna.
The structure of bundled tubes was the perfect solution for a tower that had to be accommodating the large floors needed by Sears and the smaller floors needed for rental areas.
Each tube is 22.9m (75ft) square and nine such tubes make up a typical lower floor for an overall dimension of 68.6m (225ft). This square plan shape extends to the 50th floor where the first tube terminations occur. Other tube terminations occur at floors 66 and 90, creating floor areas of from 3800 to 1100 sq.m (41,000 12,000 sq.ft).
The tower has enough steel to build 50,000 cars, enough concrete for an 8-lane highway 5 miles long, and sufficient wire to wrap around the world 1.75 times.
High-speed, double-decked elevators carry passengers at 1600 ft per second to two "sky lobbies" for transfer to local elevators. The result is similar to three 30 story buildings stacked on top of one another.
A natural grade change is created by the exterior plaza sloping to conform with the surface. This red granite surface is landscaped with bushes, potted trees, and benches surrounded by seasonal flowers.
The main lobby contains a motor-powered Calder mobile. Underneath the plaza, 3 complete levels of commercial space can be found. Tenant storage and support facilities along with boutiques, shops, 5 restaurants, and a health club are located here.
Renovations in the late 1980's and early 1990's provided a separate lobby for tourists and tenants, and renovations to the double-decker elevators.
A large bronze and stainless steel bas relief sculpture of Fazlur Rahman Khan, structural engineer of the Sears Tower, is located in the skydeck area of the building, through which tourists pass on their way to the observatory.
A street sign on the northwest corner of the intersection of West Jackson Boulevard and South Franklin Street--bordering the Sears Tower block- dedicates the intersection as "Fazlur R. Khan Way."

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