U.S. Steel Tower, Pittsburgh

The U.S. Steel Tower, also known as the Steel Building, is located on Grant Street and holds the title of Pittsburgh's tallest skyscraper. It ranks as the fourth tallest in Pennsylvania and the 37th tallest in the entire United States. Its construction finished in 1970, boasting an impressive 64 floors reaching a height of 841 feet (256 meters). Notably, the tower's design features a distinctive triangular shape with recessed corners.

An architectural milestone was achieved with the implementation of liquid-filled fireproofed columns, a groundbreaking innovation at the time. U.S. Steel strategically positioned these robust steel columns on the building's exterior to showcase the innovative Cor-ten steel. This special steel type, resistant to various weather conditions like rain, snow, and fog, forms a protective layer of dark brown oxidation over time. This coating prevents further corrosion, eliminating the need for frequent painting and expensive rust-prevention maintenance.

Initially, the weathering process led to some discoloration of the surrounding city sidewalks and nearby structures. Although a cleanup initiative was undertaken by the corporation after the weathering was completed, traces of rust remain evident on the sidewalks. The Cor-Ten steel used for the tower was manufactured at the former U.S. Steel Homestead Works. With over 44,000 U.S. tons (40,000 metric tons) of structural steel and nearly an acre of office space per floor, the tower stands as a symbol of architectural and engineering excellence.