File:Chicago (ILL) AIC, Lakeshore East " AON tower " (center) 346 mtrs 1973 (4825813645).jpg

Source : WIKIPEDIA <a href="http://en.wikipedia.org/wiki/Aon_Center_(Chicago)" rel="nofollow">en.wikipedia.org/wiki/Aon_Center_(Chicago)</a>

L'Aon Center (autrefois Amoco tower) est un gratte-ciel de Chicago, dans l'État de l'Illinois aux États-Unis. C'est le troisième plus haut building de la ville après la Trump Tower et le cinquième des États-Unis. L'Aon center (appelé à cette époque « Standart Oil Building »), éponyme de son principal occupant, Aon Corporation, a été construit par l'architecte Edward Durell Stone et terminé en 1972. En 1985, la compagnie à qui appartenait le bâtiment a changé de nom pour « Amoco Building », éponyme de la société pétrolière qui l'occupait. De 1990 à 1992, la façade du gratte-ciel qui avait été réalisée à l'origine en marbre de Carrare de 1,25" d'épaisseur (~ 30 mm) et qui avait beaucoup souffert du climat de Chicago fut rénovée et remplacée par du granite de 2" d'épaisseur (~ 50 mm). Le montant des travaux fut alors estimé entre 60 000 000 $ et 80 000 000 $. En 1998, l'Amoco center est vendu à un prix que le public n'a jamais su. Certaines personnes estiment le coût de la vente entre 430 000 000 $ et 440 000 000 $. Plus tard, l'Amoco building sera nommé «Aon center» et sera vendu de nouveau en mai 2003. Avec ses 83 étages et ses 1136 pieds (soit 346 mètres et 3 centimétres), l'Aon center était à l'époque de sa construction le plus haut bâtiment de Chicago, le deuxième aux États-Unis et le deuxième au monde. En 1974, son titre de plus haut bâtiment de Chicago lui fut enlevé avec la construction de la Willis Tower, qui culmine à 443 mètres sans mât, et à 530 mètres avec un mât. L'architecture de la tour est rectangulaire et très simple. De couleur blanche, la façade est en granite.

ENGLISH :

The Aon Center (200 East Randolph Street, formerly Amoco Building) is a modern skyscraper in the Chicago Loop, Chicago, Illinois, United States, designed by architect firms Edward Durell Stone and The Perkins and Will partnership, and completed in 1973 as the Standard Oil Building.

With 83 floors and a height of 1,136 feet (346 m), it is the third tallest building in Chicago, surpassed in height by the Willis Tower and the Trump International Hotel and Tower. The building is managed by Jones Lang LaSalle. 

Aon has the headquarters of the Aon Corporation, and it formerly had the headquarters of Amoco.

History :

The Standard Oil Building was constructed as the new headquarters of the Standard Oil Company of Indiana, which had previously been housed at South Michigan Avenue and East 9th Street. When it was completed in 1973 it was the tallest building in Chicago and the fourth-tallest in the world, earning it the nickname "Big Stan". (A year later, the Sears Tower took the title as Chicago's and world's tallest.) The building employs a tubular steel-framed structural system with V-shaped perimeter columns to resist earthquakes, reduce sway, minimize column bending, and maximize column-free space. This construction method was also used for the World Trade Center towers in New York City. When completed, it was the world's tallest marble-clad building, being sheathed entirely with 43,000 slabs of Italian Carrara marble. The marble used was thinner than previously attempted in cladding a building; this quickly proved to be a mistake. In 1974, just a year after completion, one of the marble slabs detached from the façade and penetrated the roof of the nearby Prudential Center Annex. Further inspection found numerous cracks and bowing in the marble cladding of the building. To alleviate the problem, stainless steel straps were added to hold the marble in place. Later, from 1990 to 1992, the entire building was refaced with Mount Airy white granite at an estimated cost of over $80 million. (Amoco was reticent to divulge the actual amount, but it was well over half the original price of the building, without adjustment for inflation.) Two-thirds of the discarded marble was crushed and used as landscaping decoration at Amoco's refinery in Whiting, Indiana, one-sixth was donated to Governor's State University, in University Park, Illinois, and one-sixth donated to Regalo, a division of Lashcon Inc. Under a grant from the Illinois Department of Rehabilitative Services, Regalo's 25 handicapped workers carved the discarded marble into a variety of specialty items such as corporate gifts and mementos including desk clocks and pen holders. The building's facade now somewhat resembles that of the World Trade Center due to the upward flow of the columns. The Standard Oil Building was renamed the Amoco Building when the company changed names in 1985. In 1998, Amoco sold the building to The Blackstone Group for an undisclosed amount, estimated to be between $430 and $440 million. It was renamed as the Aon Center on December 30, 1999, although the Aon Corporation would not become the building's primary tenant until September 2001. In May 2003, Wells Real Estate Investment Trust, Inc. acquired the building for between $465 and $475 million. (On August 10, 2007, Wells Real Estate Investment Trust, Inc. changed its name to Piedmont Office Realty Trust, Inc.)