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William Welde

'The John Hancock Center: A Critique

The John Hancock Center in Chicago, Illinois, has an efficient, economic, and elegant design. It was the tallest building outside of New York City when it was completed in 1969, and it stands 1,127ft tall ("View On Cities"). Fazlur Kahn, the chief engineer, designed this building to minimize materials, maximize space, and to provide the Chicago skyline with a magnificent elegant structure. He succeeded in finding scientific methods to construct this efficient, economic, and elegant skyscraper.

Efficient

Many of the scientific ideas that Fazlur Kahn came up with while designing the John Hancock Center resulted in the an extremely efficient structure. He was faced with an incredible challenge. He had to design a 100-story building that could withstand the harsh winds of Chicago. Kahn decided that one of the ways to resist the wind effectively was to have the building taper on both sides. The width of the larger side decreases by 105ft while the width of the smaller side decreases by 65ft as one travels up the exterior of the building ("View On Cities"). Another way Kahn combated the wind was to have the diagonals beams, which are seen from the facade of the building, connect to the exterior columns. The force from the wind can be carried over these mammoth braces to the columns. With this design Kahn only had to used 50% of the required steel to build the John Hancock Center in comparison to other skyscrapers built with interior columns ("Fazlur Kahn: Structural Artist of Urban Building Forms"). These ingenuities ensure that the building could handle large lateral wind forces, but the John Hancock Center is also efficient when holding up dead load. In the framed tube system gravity loads are carried down the framed exterior of the building. Every time a vertical column intersects the diagonal bracing the load distributes itself evenly through the vertical columns. This results in every vertical column holding the same amount of dead load at the bottom of the structure. Figure 1.2 illustrates that if two dead loads of 70 kips are placed on the top of the building then by the time the load hits the bottom of the structure all of the columns are supporting approximately 20 kips ("Fazlur Kahn: Structural Artist of Urban Building Forms"). (Figure 2.1 can be found in the link for "Fazlur Kahn: Structural Artist of Urban Building Forms" in the work cited). These masterful ways of dealing with lateral force and dead load prove that Kahn used his materials and load paths efficiently.

Economic

The John Hancock Building also excels economically. As mentioned earlier Kahn was able to reduce his use of steel by 50%. This means that the cost of steel was much lower than in other buildings of similar size. Another economical advantage is that there is a much higher interior space ratio in comparison to other buildings because there are less beams running through the interior of the building. This will result in more profit for the building owner because there is more space to rent out.

Elegance

The John Hancock Center also is an exceptionally symbolic and elegant structure. The building is a symbol for the state of Illinois; the proof for this fact is that in 2003 the outline of the John Hancock Center was minted onto the back of the Illinois state quarter ("Emporis"). The building’s distinctive X-bracing has made it an architectural icon. It has won awards for this style. Some of these awards include the 1970 Honor Award of the AIA Chicago Chapter and the Distinguished Architects Twenty-five year Award from the American Institute of Architects in 1999 ("Emporis"). The John Hancock Center was also inducted into the World Federation of Great Towers ("View On Cities"). These facts prove that the John Hancock Center of Chicago is higher admired elegant structure.

The X braces running along the façade of the building have caused the John Hancock Center to become an icon of a quality efficiently, economic, elegant structure. These braces free up the interior floor space while protecting the building from the legendary winds of Chicago. The John Hancock center is a lasting marvel that the state of Illinois is proud to call its own.

  Works Cited "John Hancock Center." A View On Cities. N.p., n.d. Web. 21 Feb 2012. <http://www.aviewoncities.com/chicago/johnhancockcenter.htm>. "John Hancock Center." Emporis. Emporis GMBH, n.d. Web. 21 Feb 2012. <http://www.emporis.com/building/johnhancockcenter-chicago-il-usa>. "John Hancock Center." Fazlur Kahn: Structural Artist of Urban Building Forms. Department of Civil and Environmental Engineering - Princeton University , n.d. Web. 20 Feb 2012. <http://khan.princeton.edu/khanHancock.html>.