New UK bridge designs could connect Europe and Africa across the Strait of Gibraltar

In an EPSRC-funded project, researchers at Sheffield University and Brunel University London, alongside long span bridge expert Ian Firth of engineering consultants COWI, used a mathematical modelling technique to identify new bridge forms.

Most existing long span bridges are either suspension bridges, such as the Humber Bridge, or cable-stay, such as the Queensferry Crossing.

However, as these bridge spans increase in length, more and more of their structure is needed just to carry their own weight, according to project leader Prof Matthew Gilbert at Sheffield University.

“There is a theoretical limit on how long a bridge span can be before the material fails,” said Gilbert.

So instead the researchers set out to investigate whether new designs could lead to more structurally efficient forms, allowing longer bridge spans to be built.

The researchers developed a mathematical optimisation model, in which they incorporated a nineteenth century mathematical theory by Davies Gilbert, who advised Thomas Telford on the design for the Menai Suspension Bridge in North Wales.