First And Still There
Sixty years after the world’s first cast-iron bridge was built in England, Capt. Richard Delafield of the U.S. Army Corps of Engineers erected America’s first cast-iron bridge, on the Cumberland Road. The 130-mile portion of the road from Cumberland, Maryland, to Wheeling, (West) Virginia, which opened in 1818, had been built by the federal government as a land route between the Ohio River and the Eastern states. However, as the result of niggardly allocations for maintenance, the road had quickly fallen into disrepair.
In 1832 the three states traversed by the road—Maryland, Pennsylvania, and Virginia—agreed to assume responsibility for its upkeep if the Corps of Engineers would restore it first. Most of the resulting work was strictly repair, but Delafield was responsible for building two new bridges, including one at Brownsville, in southwestern Pennsylvania, across Dunlap Creek. An early chain-suspension bridge at Brownsville had collapsed under a snow load in 1820. By 1832 an Army engineer predicted that its latest replacement “would not stand a twelvemonth.”
When the time came to build a permanent replacement, complications arose instantly. Delafield, unsatisfied with the locally available stone and concerned over the inflammability of wood, decided to make the bridge from cast iron. The several issues that had to be resolved before construction could begin—among them the selection of the exact site—were decided only after local politicking fervent enough to eventually involve even President Andrew Jackson. The Corps of Engineers briefly considered abandoning the bridge project in 1834 due to cost constraints. Delafield was unhappy with the final location, believing that it afforded “an indifferent approach”; his 1835 annual report groused that “local interests coming in collision with the public good, arrested the progress of this work.”
These matters took more than two years to resolve, after which new contracts had to be negotiated because of large increases in prevailing wages and the cost of materials (especially iron, which rose from thirty-five to fifty-five dollars per ton). To cast the iron, DeIafield rented the nearby foundry of John Snowden and paid its workers directly from federal funds. Work finally began in the summer of 1835.
The bridge Delafield designed for Dunlap Creek had a span of 80 feet with an 8-foot rise, and it contained 167 tons of iron, cast into 250 pieces. The semicircular arch consisted of five parallel tubular ribs, each made from nine identical 14-foot segments flanged at the ends and bolted together. The deck was made of cast-iron plates covered with crushed gravel. Delafield considered his bridge to be different “in its principles of construction from any of which I could find of either English or French engineers.”
Delafield had planned to build it in a year, but construction was beset with problems from the beginning. Heavy rains, high water, and labor shortages delayed progress, and by September 1836 contractors had completed only one stone abutment. Meanwhile, at the foundry, casting had begun, but the second year of construction ended with several large pieces still not cast. Delafield expected the remaining work to take another two months, but despite his confidence, the bridge was not completely finished until 1839, long after all other improvements on the road had been finished (though it began to carry traffic as early as July 1838). After placement of the roadway plates and iron rail, and three coats of white lead paint, the bridge was officially opened on July 4. By this time Delafield had been reassigned as superintendent of the U.S. Military Academy.
It ended up costing almost $40,000, although Delafield’s 1833 estimate had been $21,000. This made it exorbitantly expensive; a comparably sized stone bridge would have cost about $23,000, and a wooden one $7,000. Only the federal government could afford to pay so much. It’s no surprise, then, that Delafield’s design, despite its evident sturdiness, was not widely copied, and America’s next iron arch bridge was not built until 1858.
Over the years, few alterations have been made to the nineteenth-century structure. In the 1920s the state added sidewalks supported by cantilevers, but no other major changes have been necessary to keep Delafield’s hard-won bridge in service. Today, after more than a century and a half, it continues to carry traffic across Dunlap Creek. It is so inconspicuous that many motorists do not even realize they have crossed a bridge at all—let alone the oldest iron bridge in the country.
