Bigger and Stronger

The man who takes America to the top in steel is Andrew Carnegie, who gets his start with the Pennsylvania Railroad. After realizing how dependent the railroads are on steel, he decides to move into steel production.

By the time he is done, Pittsburgh is the leading producer of steel, by a country mile. The city is already a leader in iron, but Carnegie's vision transforms it into the world's leading producer of steel.

Carnegie starts by buying up existing iron and steel mills, beginning with Homestead Steel, just outside Pittsburgh. He adds a huge new Bessemer converter, and is on his way to building an empire based on steel rails.
Carnegie Steel, 1890

  One-Man Empire
Carnegie's Homestead steel works (at right) are the biggest in the world. The blast furnaces producing the iron are visible in the far distance, near the top of the image. Other buildings house rolling mills, producing steel rails for railroads. America's first major union strike occurs at his Homestead plant, lasting four months before collapsing.

Bridges, 1890

  Steel Takes Over
Structural steel is first used in bridges. Before the Civil War, bridges are supported by a structure of wooden beams (top left). When iron takes over, the longest wrought iron bridge span is 320 feet (center top). The bridge across the Ohio River uses iron cables to support an iron girder span (top right). When a bridge is needed to cross the Mississippi River at St Louis, calculations indicate that wrought iron simply isn't strong enough to support the 520-foot span required. The solution is an all-steel bridge (bottom).


Steel-frame buildings, 1890

  Structural Skeleton
To make stronger, taller buildings, steel girders are riveted together to provide a rigid cage-like skeleton. This supports a thin masonry facade, with large window openings. Steel suppliers publish data to assist with calculations. When equipped with elevators suspended on steel cable, 12-story buildings are now possible. The Otis Safety Elevator creates a sensation before the Civil War, when it demonstrates the special brake that keeps the platform from free-falling, after the cable is disengaged( top center).