Willis (Sears) Tower
The Willis Tower, formerly known as the Sears Tower is the tallest building in Chicago and one of its most popular tourist attractions. This is not surprising since it is one of the tallest buildings in the world at an amazing 110 stories, or 1,730 ft including the antenna on top (1,450 ft without the antenna). In fact, it held the title as the tallest building in the world from 1973 until 1998. Illinois, Indiana, Wisconsin, and Michigan can all be seen from the observation deck. Located on the 103rd floor, the Skydeck in the tower is the 7th highest in the world. There are around 25,000 people that flock to the tower daily just to catch a glance of these views and for some to face their fears of heights (History and …show more content…
decided that it wanted to combine all it’s Chicago employees into one building. On July 27, 1970, Sears announced to the world that they would be constructing a building that not only was the largest office building ever built at 4,500,000 square feet, but was also the tallest building ever built at that time at 110 stories tall. It was 100 feet taller than the World Trade Center in New York. The design of the building was a monumental task that was undertaken by Skidmore, Owings, and Merrill. It was originally built to accommodate the growth that the company was expected to have, with Sears only using around half of the space originally, but eventually, much of the space turned into residential, retail space, and office space for other companies (Kerch, 1991). In 2009, Willis Holdings agreed to list part of the buildings and receive naming rights, so the Sears Tower became the Willis …show more content…
The architecture and engineering firm hired with the task of designing and constructing the tower, SOM, assigned Bruce Graham and Fazlur Khan to the project. They implemented a bundled tube design that was the first of its kind on such a large project that paved the way for the design and construction of future skyscrapers. This design allowed for 4.5 million square feet of office space, more customization of the floor layouts, up to 3 foot of sway within the building, and the stiffness needed to stay standing at the height in which it was built. The tubular design also allowed Sears to save about $10,000,000 on steel alone compared to previously used steel frame designs. Additionally, SOM managed to save 95% of the time usually spent welding by using prefabricated parts referred to as Christmas trees. This not only majorly sped up the process, but allowed Sear to save on labor costs. In addition to 3 trussed layers in the building, there were trusses and spandrel beams designed into every floor to help the load distribute more evenly.
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