ABSTRACT
Today the Gateway Arch, together with the courthouse and the Museum of Westward Expansion, form the Jefferson National Expansion Memorial, which is part of the US National Park Service. The St. Louis arch was one of Saarinen's first major works done without the collaboration of his architect father, Eliel. The younger Saarinen won a design competition in 1947 for this project. His design was meant as a tribute to Thomas Jefferson and St. Louis, as well as a celebration of technology and the modern era. The foundations were tensioned using steel bars because, while concrete has excellent strength in compression, it requires the additional tensile strength of steel to form a material that excels in both tension and compression. Most of Gateway Arch's sections were partially assembled off-site, then welded and bolted together in position at the construction site. The overall shape of the arch is a particular type of curve, called an inverted catenary.
