John Hancock Center Built

John Hancock Center at 875 North Michigan Avenue in the Streeterville area of Chicago, Illinois, is a 100-story, 1,127-foot (344 m) tall skyscraper, constructed under the supervision of Skidmore, Owings and Merrill, with chief designer Bruce Graham and structural engineer Fazlur Khan. When the building topped out on May 6, 1968, it was the tallest building in the world outside New York City. It is currently the fourth-tallest building in Chicago and the sixth-tallest in the United States, after the Willis Tower, the Empire State Building, the Bank of America Tower, the Trump Tower Chicago, and the Aon Center. When measured to the top of its antenna masts, it stands at 1,506 feet (459 m). The building is home to offices and restaurants, as well as about 700 condominiums and contains the third highest residence in the world, after the Trump Tower also in Chicago and the Burj Khalifa in Dubai. This skyscraper was named for John Hancock Mutual Life Insurance Company, a developer and original tenant of the building.

One of the most famous buildings of the structural expressionist style, the skyscraper's distinctive X-bracing exterior is actually a hint that the structure's skin is indeed part of its 'tubular system'. This idea is one of the architectural techniques the building used to climb to record heights (the tubular system is essentially the spine that helps the building stand upright during wind and earthquake loads). This X-bracing allows for both higher performance from tall structures and the ability to open up the inside floorplan (and usable floor space) if the architect desires. Original features such as the skin have made the John Hancock Center an architectural icon. It was pioneered by Bangladeshi-American structural civil engineer Fazlur Khan and chief architect Bruce Graham. Unlike the Willis Tower, the building's antenna masts are the same height, which gives the building a much more symmetrical appearance, despite several similarities in the design of the two buildings.
The interior was remodeled in 1995, adding to the lobby travertine and textured limestone surfaces. The elliptical-shaped plaza outside the building serves as a public oasis with seasonal plantings and a 12-foot (3.7 m) waterfall. A band of white lights at the top of the building is visible all over Chicago at night and changes colors for different events. For example, at Christmas time the colors are green and red. When a sports team goes far in the playoffs, the colors change, too. When the Chicago Bears made the Super Bowl the colors were blue and orange.
The building is a member of the World Federation of Great Towers. It also has won various awards for its distinctive style, including the Distinguished Architects Twenty-five Year Award from the American Institute of Architects in May 1999.

Including its antennas, the John Hancock Center has a height of 1,500 feet (457 m), making it the fifth-tallest building in the world when measured to pinnacle height (after Burj Khalifa, Willis Tower, the Shanghai World Financial Center, and Taipei 101).

Known locally as 'Big John', the John Hancock Center is one of the Chicagoans' favorite skyscrapers. The 100 - story building, completed in 1969, has a remarkable design, with the huge X-braces serving both a structural and a visual purpose. Visually, it gives the impression of stability and it moves the eye away from the human-sized windows.

The construction was designed by the engineer Fazlur Kahn and architect Bruce Graham from Skidmore, Owings & Merrill. Fazlur Kahn devised the frame-tube system, which he also implemented in the Sears Tower.

This new construction method was made possible by new technologies, like more advanced software and new developments in steel. Thanks to the new construction method, it was possible for Kahn to design constructions which could resist the strong windforces more effectively by having the forces absorbed by all three dimensions of the building. The diagonals are connected to the exterior columns, making it possible for the forces to be carried over from the braces to the columns and back. The innovative construction also resulted in a 50% decrease of required steel compared to skyscrapers built with interior columns.

Just like Marina City, the John Hancock Center is a multifunction building. It includes 48 stories of apartments (with a total of 711 apartments), 29 stories offices, shops, a hotel, a swimming pool, an ice rink, restaurant and on top of the 344 meters (1127 ft) tall building radio and television facilities. On top it offers services like its own post office and a refuse collection. The apartments are located at the top of the tower. Some of them are so high that the inhabitants sometimes have to call the doorkeeper to ask what the weather's like down on the ground, as the apartments are sometimes above the clouds.

At the beginning of the project, it was controversial mostly because of the location of this massive tower, near the much smaller and more gentle buildings on Michigan Avenue. After its completion, most of the criticism dwindled, but much like with the Sears Tower, the plaza at the entrance was considered very user- unfriendly, being afflicted by heavy gales and loud traffic noise from Michigan Avenue. It was redesigned in 1995 and now includes a 3,5 meters high fountain to muffle the noise and a recirculation of office and shopping traffic.