I read with interest your article on the South Stockton Link Road (NCE 30 October). While it correctly identified the innovative nature of the twin tunnels to carry the new road over railway lines, it failed to mention Stirling Maynard and Partners' major contribution as UK lead designers.
The twin tunnels are constructed in corrugated steel with a bending stiffness nine times greater than hitherto used in the UK. Due to this and other features of the corrugated steel structures including their very large span, it was necessary to obtain significant departures from standard from the Highways Agency.
These departures were obtained by Birse Civils with major input from Stirling Maynard as lead designers, acting for supplier Asset International.
Peter Beveridge, director, Stirling Maynard and Partners, www. stirlingmaynard. com