St. Louis’s 192 m stainless-steel arch (completed 1965) spans a true weighted catenary. Saarinen’s winning 1947 design symbolizes westward expansion as part of the Jefferson National Expansion Memorial. Tram capsules, structural monitoring, and riverfront redesigns sustain a mid‑century masterpiece on the Mississippi.
Eero Saarinen’s competition entry (with structural engineer Hannskarl Bandel) envisioned an elegant, mathematically pure catenary. The arch’s legs house inclined trams conveying visitors to a small observation room at the apex.
Triangular cross-sections taper toward the top; a double-wall system sandwiches carbon-steel framing between inner and outer stainless skins. Precision segment fabrication and post-tensioning achieved millimetric closure at the apex.
Recent CityArchRiver projects improved access, museum interpretation, and riverfront ecology. Sensors track thermal movement and wind behavior; maintenance polishes and protects the steel skin against staining.
