MT 118/235

M1: Hendon Urban Motorway; southern extension, Staples Corner interchange (Southern terminus of M1); discussions of engineering problems including small bridge over river leading to Welsh Harp Reservoir

Date range	1966-1971
Location	National Archives (see all files stored here)
Catalogue	See entry
File base	Series MT, subseries MT 118

Context

Despite the title, this concerns the section of M1 opened in 1977 between junctions 1 and 2, and is actually mostly about the flyover carrying the A406 North Circular at Staples Corner. It's not about the Hendon Urban Motorway between junctions 2 and 4.

It comes as a large box containing paperwork and a big folder of plans and more papers. The paperwork covers every angle of flyover design, from initial discussions about whether it should be engineered to carry excess loads to diversionary routes during construction, spacing of piers, span lengths, vertical curvature and guard rails. There's an extended discussion about the location of lighting columns in relation to the parapets and a debate over protective paint for steelwork. You can also, if you wish, read a report on precast units in bridge design, a detailed submission to the Royal Fine Art Commission, and a series of calculations of shear forces and stresses on bridge beams.

The plans show the A406 flyover as built, and all have a miniature key plan of the whole interchange in one corner, which is shown as built. They are all variations on a theme and include access points for maintenance of steel box girders, a design for a mobile painting gantry, cross-sections, sign gantries, service ducts, etc.

People with camera copies

None known.