The American Bridge Company is a civil engineering firm that specializes in building and renovating bridges and other large civil engineering projects. Founded in 1900, the company is headquartered in Coraopolis, Pennsylvania, a suburb of Pittsburgh. The firm has built many bridges in the U.S. and elsewhere; the Historic American Engineering Record notes at least 81. American Bridge has also built or helped build the Willis Tower, the Empire State Building, the Chrysler Building, launch pads, resorts, and more. During World War II, it produced tank landing ships (LSTs) for the United States Navy. Competitors include Walsh Group, Flatiron Construction, and Skanska USA. Related companies include American Bridge Holding Company and American Bridge Manufacturing Company, both also headquartered in Coraopolis. American Bridge Company was founded in April 1900, when JP Morgan led a consolidation of 28 of the largest U.S. steel fabricators and constructors. The company’s roots extend to the late 1860s, when one of the consolidated firms, Keystone Bridge Company, built the Eads Bridge at St. Louis, the first steel bridge over the Mississippi River and still in use. In 1902, the company became a subsidiary of United States Steel as part of the Steel Trust consolidation. The company pioneered the use of steel as a construction material; developing the means and methods for fabrication and construction that allowed it to be widely used in buildings, bridges, vessels, and other plate applications. It went on to do work across the nation and around the world.