The Iron Bridge - How was it Built?

Page 1 of 6

• 1. A construction mystery
• 2. Building begins
• 3. Arches and ribs
• 4. Deck bearers
• 5. Facts and figures
• 6. Find out more
• Print entire article

A construction mystery

Despite its pioneering technology in 1779, as the first structural use of cast iron, no eye witness accounts are known which describe the Iron Bridge being erected. However, recent discoveries, research and experiments have shed new light on the mystery of exactly how it was built, challenging the assumptions of recent decades. In 1997 a small watercolour sketch by Elias Martin came to light in Stockholm. Although there are a wealth of early views of the Bridge by numerous artists, this is the only one which actually shows it under construction.

In October 2001 a half-size model was built to reproduce the watercolour and test its credibility as an engineering solution. Meanwhile, a detailed archaeological, historical and photographic survey was done by the Ironbridge Gorge Museum Trust, along with a 3D CAD (computer-aided design) model by English Heritage.

The results of these discoveries and experiments tell us a lot more about how the Bridge was built. We now know that all the large castings were made individually as they are all slightly different. The joints would all be familiar to a carpenter - mortise and tenons, dovetails and wedges - but this was the traditional way in which iron structures were joined at the time.

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Published: 2002-01-01