U.S. Steel Tower, also known as the Steel Building (formerly the USX Tower), is the tallest skyscraper in Downtown Pittsburgh, Pennsylvania, and the 35th tallest in the United States. Completed in 1970, the tower has 64 floors to 841 ft (256 m) and has 2,300,000 square feet (214,000 m 2) of leasable space. Its original name was the U.S. Steel Building for many years before it was changed to USX Tower in 1988. The name was finally changed back to the U.S. Steel Tower in January 2002 to reflect U.S. Steel's new corporate identity (USX was the 1990s combined oil/energy/steel conglomerate). Although no longer the owner of the building, U.S. Steel is one of the largest tenants, occupying more than a half million square feet (46,452 m²) of office space. The building is located at 600 Grant Street, ZIP code 15219.

History
In the planning stages, U. S. Steel executives considered making the building the world's tallest, but settled on 840-ft (256-m) and the distinction of being the tallest building outside New York City and Chicago. However, it eventually lost even that distinction to newer buildings erected across the United States. Prior to 1970, the tallest building in Pittsburgh, at 44 stories, was the Gulf Building. Now an office complex known as Gulf Tower, it was the original headquarters of the Gulf Oil Corporation. The U. S. Steel Tower is architecturally famous for its triangular shape with indented corners. The building also made history by being the first to use liquid- fireproofed columns. U. S. Steel deliberately placed the massive steel columns on the exterior of the building to showcase a new product called Cor-ten steel. Cor-ten resists the corrosive effects of rain, snow, ice, fog, and other meteorological conditions by forming a coating of dark brown oxidation over the metal, which inhibits deeper penetration and negates the need for painting and costly rust-prevention maintenance over the years. The initial weathering of the material resulted in a discoloration of the surrounding city sidewalks, as well as other nearby buildings. A cleanup effort was orchestrated by the corporation once weathering was complete to undo this damage, but the sidewalks still have a decidedly rusty tinge. The Cor-Ten steel for the building was made at the former U. S. Steel Homestead Works. Rockwell International Corporation, which had its headquarters in the building until the mid 1980s, displayed a large model of the Rockwell-designed NASA Space Shuttle in the building's lobby until it moved to other facilities. The tower contains over 44,000 U.S. tons (40,000 metric tons) of structural steel, and almost an acre of office space per floor.

Features

Internal systems
The U. S. Steel Tower features several redundant systems that have allowed the building to remain free of unplanned service interruptions since it was constructed. It is fed by two redundant water mains, one from Grant Street and one from 7th Avenue. Both are fully maintained and tested annually. There is a fail over system in place, and either main will automatically meet the water demands of the building in the event of a failure. In addition, the building has four redundant water pumps, any one of which can meet the needs of the entire building. The building also has four redundant electrical feeds, which come from several substations. Finally, the building has fully redundant heating and cooling systems, including two boilers and two air chillers. The heating boilers can burn either natural gas or #2 fuel oil. There is no fail over, but manual adjustment of the system in the event of a supply shortage takes only minutes.

Signage
The University of Pittsburgh Medical Center leased several floors of the tower, which now serves as the institution's headquarters, in 2007. To go along with this lease, the company also purchased new signs reading "UPMC" for the top of each three sides of the building. The Pittsburgh Planning Commission approved the 20-foot (6.1 m) signs , and the majority of the letters were installed via helicopter lift on June 7–8, 2008.

Nativity scene
Each year, a famous creche or nativity scene goes on display in the building's courtyard. It is larger than the original nativity, and is the only creche nationally to be authorized by the Vatican.

Roof
Unlike many buildings of similar heights, the U.S. Steel Tower does not taper in width from its lower floors to its higher floors. Accordingly, the tower sports the "largest roof in the world at its height or above", at a size of approximately one acre. This flat expanse was once used as a heliport, but as of January 2010, it had sat dormant for 18 years. High Point Park Investigation An organization known as the High Point Park Investigation was formed to explore the possibility of converting the dormant roof of the U.S. Steel Tower into an attraction of some sort—a "pinnacle of perspective where people go to see the view, a signature landmark like the Eiffel Tower or the Empire State Building". This transformation could take the form of a nature park, a gallery space, or some other type of attraction. The High Point Park Investigation is based at Carnegie Mellon University's STUDIO for Creative Inquiry and has received the endorsement of regional organizations including the Pittsburgh Parks Conservancy and VisitPittsburgh.com. As of January 2010, the building's owner has expressed no interest in developing the roof of the tower, but public interest in the potential of such a project has been high.

Sightseeing
On clear days, it is possible to spot the U. S. Steel Tower from as far as 50 miles away, from the top of Chestnut Ridge in the Laurel Highlands southeast of the city.

Fictional portrayals
The U. S. Steel Tower makes an appearance in the movie Dogma as the headquarters for Mooby Corp., owner of the Mooby the Golden Calf media empire. It also figures prominently in the movie Sudden Death as a staging area for the group planning to take the U.S. Vice President as a hostage, and in Boys on the side .