The Iron Bridge of Shropshire

The world’s first cast iron bridge still stands in Shropshire, England, across River Severn. It’s more than two hundred years old. Although cast iron has been used since ancient times to make pots and pans, cannon balls, and decorative pieces such as window grills and chimneypieces, it was never used for structural purposes until architect Thomas Farnolls Pritchard suggested that a cast iron bridge be constructed to span the Severn Gorge in Shropshire. The Severn Gorge, later renamed to the Ironbridge Gorge after the bridge, is rich in coal, iron ore, and limestone, and a significant industry developed in the area to exploit these resources during the later part of the 18th century. Photo: Bs0u10e0/Flickr As the industry around the gorge grew, there arose the need for a strong and durable bridge to transport goods across the river. Because the gorge was deep and the banks instable, the bridge had to be single span and sufficiently high to allow tall ships to pass underneath, the river being a key trading route. The only material that was acceptable was cast iron, but nobody had built a cast iron bridge at this scale before. An iron bridge was begun at Lyons in 1755, but was abandoned because of cost, and a 22-meter-span wrought iron footbridge exist over an ornamental waterway in Kirklees, Yorkshire, since 1769. Undaunted, architect Thomas Farnolls Pritchard proposed an iron bridge which would link the parishes of Madley and Benthall over one of the busiest rivers in the country. Pritchard’s designs were approved by Act of Parliament and in 1777 construction began. Abraham Darby III, an ironmaster at Coalbrookdale, was commissioned to cast and build the bridge. When Pritchard died just a month after work had begun, the responsibility of the project fell upon Darby.