Iron Bridge

Curriculum topics available: Mechanics and engineering.

Nestled in a spectacular wooded gorge stands a monument to British industry – the world’s first iron bridge. Crossing the River Severn, it was completed in 1779 and opened to traffic in 1781. It became a UNESCO World Heritage Site in 1986 and remains an iconic feature of Britain’s industrial past.

Although Darby commissioned many paintings and engravings of the finished bridge, a lack of images or eyewitness accounts meant that, for over 200 years, little was known of exactly how Darby managed to erect this structure of almost 400 tons.

But in 1997 a small watercolour sketch by Elias Martin, which illustrated the building of the bridge, was discovered in a Stockholm museum. This exciting find, along with recent research, revealed much about the building process.

While Darby’s accounts suggest the use of scaffold poles, timber and rope during construction, Martin’s painting shows a wooden framework used to raise the half-ribs from the deck of a vessel.

Research also revealed that 70% of the components of the bridge – including all the large castings – were made individually to fit, and all differ slightly from one another as a result. Darby’s workers employed joining techniques used in carpentry, such as dovetail and shouldered joints, adapting them for cast iron.

Curriculum topics available: Engineering.

A symbol of the Industrial Revolution, the Iron Bridge is much more than just a bridge. As the first bridge made of cast iron, the Iron Bridge is one of the wonders of the modern world and set a new, exciting precendent for engineers around the world. It was 1779 and the surrounding area was a bustling hub of industrial activity at the forefront of what would become known as the Industrial Revolution. The bridge was so successful that it gave its name to the whole Ironbridge Gorge.

Curriculum topics available: Forces.

Your students can learn about how science can be used practically to conserve world heritage sites like Iron Bridge.
In 2017-18 we undertook a major conservation project to restore the Iron Bridge, due to stresses in the ironwork since its original construction. There has also been disruptive ground movement over the centuries and an earthquake at the end of the 19th century.

We cast more than 300 bespoke iron wedges to replace those which support the deck. A team of six painters then applied 2,400 litres of paint to return to bridge to its original red-brown hue after new evidence came to light during the conservation process.