Antony Gormley is one of Britain’s most famous artists. In the 1990s he was commissioned to create a monumental sculpture to herald arrival into England’s northeast region. However, he knew his design couldn’t withstand the 100mph winds of its hilltop location, so he came to Arup to help engineer a solution.

Originally, it was assumed Gormley’s design would need to be altered, making the sculpture’s ‘ankles’ thicker as a base. Arup engineers suggested switching materials, to Cor-ten steel with 20m of foundation anchoring it underground. Not only does Cor-ten make it stronger, its steel-copper alloy formed a rusty patina making an attractive appearance that didn’t need regular painting. 

The Angel of the North was built by Gormley to last 100 years. Thanks to Arup’s design, it will. In the 25 years since it was built, the sculpture has become one of the best-known public artworks in Britain, an icon that people all over the country equate with the northeast.

Structural engineering: built to last

Originally it was thought necessary to make the ankles thicker as a top-heavy sculpture would be in danger of falling over in 100mph winds. But the fabricator specified strengthened steel ribs to transmit the wind loads through to the foundations, enabling the slim ankle shape. Beneath the ground, we used 700 tonnes of concrete and 32 tonnes of reinforcing steel in the foundations extending down 20 metres, anchoring it to the solid rock beneath. 

Using the right materials

Sculptures are often cast in bronze but something stronger was needed, so steel was specified. The cost of repeatedly painting conventional steelwork, or using stainless steel, was too high so we suggested using Cor-ten steel. Cor-ten is a special alloy that combines steel and copper that forms rusty patina during the first few years of exposure. This low maintenance and visually attractive finish protects the structure from environmental corrosion.

The most important thing is that this was a collaborative venture. We were evolving a collective work from the firms of the North East and the best engineers in the world. 

Sir Antony Gormley