M4. Almondsbury Four Level Interchange (J20)

The design of this interchange has been the subject of a Paper presented to the Institution of Civil Engineers by O.A. Kerensky CBE and N.J. Dallard on 19th November 1968 and reported in the Proceedings Volume 40 pages 295 to 321 and volume 43 pages 483 to 495.

Almondsbury Four Level InterchangeThe interchange was a novel design at the time providing high speed freeflow all-directional movements between the two motorways by means of roads at four levels. The Abutments to the bridges are skew and the columns are articulated by means of spherical bearings at each end. The contract included about 2.5 miles of dual carriageway motorway and 4.5 miles of slip roads. It also included the M5/A38 (J16) interchange and the 36 ft wide collector/distributor roads between the two junctions.

Contractor Richard Costain Ltd. was awarded the contract at an estimated cost of £1.9m and commenced work in May 1964. The ground conditions at the site, which were in various stratas of marls, lias and limestone, were troublesome and had to be blasted on excavation. However the works were completed in time for the opening ceremony undertaken by Her Majesty the Queen in September 1966. There are a number of documents referring to the interchange including newspaper cuttings, photographs, papers given to associations and pictures of the opening ceremony. An interesting newspaper article from the Western Daily Press concerns Oleg Kerensky who was the Partner in charge of the project for Freeman Fox and a visit he paid to the contract with his 84 year father Mr. Alexander Kerensky better known as the Russian Leader who endeavoured to build a liberal Russia after the fall of Czar Nicholas II in 1917.