science · 04 July 1874 · 150 years ago
official opening of Eads Bridge (combined road and rail steel arch) over the Mississippi River at St. Louis, Missouri, designed by James B. Eads. It is the longest arch bridge in the world at this time, with an overall length of 6,442 feet (1,964 m); the first use of true steel as a primary structural material in a major bridge project; the first built using cantilever support methods exclusively; and the first major project to make use of pneumatic caissons.
OnThisDay.net