The Chicago Sears Tower

I. Introduction

The Sears Tower is the tallest skyscraper in Chicago, but also in the United States. Moreover, it has been the world’s tallest building from 1973-1998. Located in the heart of Chicago Down- town, also called the “West Loop” – the city’s premier submarket and home to its largest corporations and commuter rail stations – the Sears Tower today occupies a significant position in Chi- cago’s city center.

The first skyscrapers were invented in the late 1800s and Chi- cago has played a major role in the invention. It has been the site of many of the skyscrapers’ stylistic and technical advances. In the phenomenal growth years after the Chicago Fire of 1871, a pool of architectural talent known as the First Chicago School advanced the skyscraper form we know now. This is the reason why the city is also known as “the birthplace of skyscrapers”.

II. Idea and planning

All started in the late 1960s, when Sears, Roebuck & Company, the world’s largest re- tailer with about 350,000 employees at that time, decided to consolidate its administrative operations into one building on the western edge of Chicago’s Loop. The company needed 300,000 m² of office space for its 13,000 employees in their major departments. The first architects proposed a tower with a boxy structure which would have large 5,000 m² floors in the lower part of the building. But the real estate advisors voted for a taller tower for their headquarters to build something special. So in July 1970, the plans for the building slowly stretched to 420,000 m². According to Sears, it should be "as tall as the FAA will let us go." (The so-called Federal Aviation Administration is an American agency with regulates the air traffic in the United States.) A quotation from Bruce Graham, one of Sears’ architectural creators, shows the com- pany’s sophisticated plans:

“Tall buildings are man-made. Towers have historically been not only the pride of their temporary owners, but of their cities as well. So the Sears Tower, one more mountain, was created for this city on the plains [...], but unlike most tall buildings in New York, it is a tower of the people, not the palace of a bank.”

III. Construction

Construction commenced in August 1970, and the building reached its originally antici- pated maximum height on May 3, 1973. Commissioned by Sears, Roebuck and Company, it was designed by chief architect Bruce Graham and structural engineer Fazlur Khan of the architectural and engineering firm Skidmore, Owings and Merrill. When completed, the Sears Tower had overtaken the roof of the World Trade Center in New York City as the world's tallest building, which just got the title a few months ago. The tower finally had 110 stories, including the main roof and the mechanical penthouse. Its total height, measured from the east entrance, amounted to 442 m without antennas.

However, Sears' optimistic growth projections never came to pass. Not only competition from traditional rivals like Wal-Mart continued, but also the fortunes of Sears & Roebuck declined in the 1970s due to lost stock transactions. Moreover, the Sears Tower itself was not

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the draw Sears hoped it would be. It was restricted in height by a limit imposed by the FAA to protect air traffic, which made it impossible to enlarge the building in future. As a result, half of the tower stood vacant for a decade as more office space was erected in Chicago in the 1980s. The company began moving its offices out of the Sears Tower in 1993 and started its activities in a new office campus in Illinois.

The tower itself underwent three major renovations: the first one made in 1982, adding the communication mast and two television antennas increasing its total height to 520 m; the sec- ond renovation took place in the early 90s, adding the atrium and a remodeled lobby; and with the third one in the year of 2000, four HDTV antennas were installed and the western antenna was extended.

The skyscraper was financed completely out of Sears' pockets. In the end, the construction came up to approximately $150 million USD at that time, which would be equivalent to roughly $950 million USD today. (For comparison, comparable skyscrapers build today cost around the equivalent of $1.7 billion dollars.) In the years since, the skyscraper has gone through several owners, but Sears has acquired the naming rights for the building. Therefore, it is still called “Sears Tower”, even though the company already moved out 15 years earlier.

IV. Design

Today, the Sears Tower is a multi-tenant office building with more than 100 different companies in residence, including major law firms, financial services firms and insurance companies. Approximately 25,000 people enter the building every day – having the choice between 104 elevators.

The skyscraper’s security system is very sophisticated and well thought-out, being one of the most complete life safety systems ever devised for a high-rise building. The whole steel construction is fireproofed. Moreover, the tower does not just have automatic sprinklers, fire extinguishers, duct-mounted smoke detectors and a computer-activated system. In the event of an electrical failure, there are also special elevators people can use to escape from fire or other dangers.

The Sears Tower’s exterior mainly consists of black aluminum and bronze-toned glass as well as a steel frame with a bronze-tinted glass curtain wall. Even the building’s whole design is unique. It incorporates 9 steel-unit square tubes in a 3 tube by 3 tube arrangement – all end- ing in different heights. The tower was the first building for which this design was used. It allows future growth if wanted or needed. And due to this unique design no other skyscraper offers such a variety of different views like the Sears Tower.

Besides a 160-car executive parking garage, the property also features a world-class broadcast platform, full-service conference center, fitness facilities, and excellent technology features and multimedia equipment.

V. The Skydeck

The Sears Tower Skydeck opened on June 22, 1974 and is located on the 103rd floor of the tower. 412 m above the ground, it is one of the most famous tourist attractions in Chicago. In either of two special elevators, who are among the fastest in the world, it takes about 45 seconds to get to the top. 1.5 million tourists visit the Skydeck annually. A second observation deck on the 99th floor is used when the 103rd floor is closed.

Visitors can see far over four different states: the plains of Illinois and across Lake Michi- gan, as well as the states of Indiana, Michigan and Wisconsin. On a clear day, you can view

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