Willis Tower, Chicago, USA
Height (Architectural): 442 mHeight (Occupied): 412 mFloors: 108Observation Decks: 412.7 m
The construction of the Willis Tower started in 1970 and was completed on May 3, 1973. It was the tallest building in the world for nearly 25 years! It is still (2012) the tallest building in American Continent and will hold Top ranking position till completion of New York's 541 meter high One World Trade Center in 2013. Until 2009 the building was called Sears Tower and even today many Americans as well call it so far. Comfort - is what can be said about the building: world-class broadcast amenities, perfect renovated sky deck, fully equipped conference center etc. This elegant building like a magnet attracts 25,000 visitors every day.
The building project involved world class professionals which implemented brilliant construction ideas and long years of experience resulted in the construction of the tower, which still remains one of the prominent high rise buildings worlds over. Architectural and engineering design was made by eminent Skidmore Owings & Merrill; the general contractor was Morse Diesel International. The design was inspired by an advertisement for a package of cigarettes.Structural material used for the building is steel; facade is made from black aluminum and dark glass in curtain wall system.
This luxurious building which cost approximately $150 million was designed in a "mega-module" system and international architectural style. The tower has prominent construction specificity, "heat tracing", that amazingly melts snow off the glass. Another invention -six automated machines wash the windows of the Tower 8 times in a year.
Building reconstruction in the 1980s resulted in adding a barrel-vaulted entrance hall to the west part of the Tower. In January 2009, the Willis Tower owners began a major renovation of the Sky deck and added all-glass box balconies which allow visitors to look through the floor to the Chicago streets 413 meters below. Designed by the same SOM the boxes can bear about 5 tons of weight.
By Lusi Barseghyan, www.building.am