Eads Bridge

About

The Eads Bridge is a combined road and rail bridge over the Mississippi River connecting the cities of St. Louis, Missouri, and East St. Louis, Illinois. It is located on the St. Louis riverfront between Laclede's Landing to the north, and the grounds of the Gateway Arch to the south. The bridge is named for its designer and builder, James Buchanan Eads. Work on the bridge began in 1867, and it was completed in 1874. The Eads Bridge was the first bridge across the Mississippi south of the Missouri River. Earlier bridges were located north of the Missouri, where the Mississippi is narrower. None of the earlier bridges survived, which means that the Eads Bridge is also the oldest bridge on the river.

To accommodate the massive size and strength of the Mississippi River, the Eads Bridge required a number of engineering feats. It pioneered the large-scale use of steel as a structural material, leading the shift from wrought-iron as the default material for large structures. Its foundations, more than 100 feet below water level, were the deepest underwater constructions at the time. They were installed using pneumatic caissons, a pioneering application of caisson technology in the United States and, at the time, by far the largest caissons ever built. Its 520-foot center arch was the longest rigid span ever built at the time. The arches were built suspended from temporary wooden towers, sometimes cited as the first use of the "cantilever principle" for a large bridge. These engineering principles were used for later bridges, including the Brooklyn Bridge, which began construction in 1870.