A57(M). Mancunian Way

The Mancunian Way, nearly 2 miles in length included the first section of truly urban motorway to be constructed in the Region.

It is a lateral road along the southern fringe of the central area of the City of Manchester. Its primary purpose was to carry the traffic, much of it commercial, moving between the industrial areas on the east side of the conurbation through to Manchester Docks and Trafford Park. Formerly, most of this traffic had to pass through the centre of the City and, in consequence, caused considerable congestion.

A further important function of the road was to act as a distributor between the heavily trafficked main radial roads south of the City centre.

It was the intention that it would form part of a comprehensive network of urban motorways envisaged in the SELNEC (South East Lancashire and North East Cheshire) Highway Plan of 1962.

The early proposals for the route were formulated in 1959, following traffic surveys carried out by the then City Engineer and Surveyor. It was decided that the road would have to be elevated on the section from west of Medlock Street to just east of Sackville Street, a length of approximately 1400 yards. This was the only practicable way of providing the necessary grade separation at the closely spaced intersections of the motorway with Medlock Street, Cambridge Street, Oxford Road and Brook Street, all of which are important radial routes.

The City Council was the Highway Authority for the scheme and the design of the ground level roads, service diversions, drainage and landscaping was carried out by the City Engineer and Surveyor. G Maunsell & Partners, Consulting Engineers, were appointed to undertake the design of the elevated structure and the supervision of the construction of all the works.

The statutory procedures for the other motorways in the Region were undertaken in accordance with the requirements of the various Highways Acts applicable at the time. In contrast, the Corporation promoted a Parliamentary Bill to authorise the construction of the Mancunian Way and this received Royal Assent in 1961.

The project was carried out in two stages. Work on the first stage, which involved the construction of a 950 yard length of all-purpose length of dual carriageway east of A6, started in November 1963. It was opened to traffic in November 1965.

Mancunian WayThe second stage, between A6 and the A56 was designed as a motorway and construction commenced in December 1964. It included the elevated section, which is a prestressed concrete structure 3232 feet 6 inches long between the end abutments. Of the thirty two spans, twenty eight are each 105 feet long, two are 60 feet to accommodate ground level features and the eastern and western spans are 97 feet 6 inches and 75 feet respectively.

Between Cambridge Street and Brook Street the layout changes from dual two-lane to dual three-lane carriageways. With a lane width of 11 feet, the overall width of the eastern part of the structure is 79 feet and elsewhere, 61 feet. Ramped connections from the local road system are provided at Cambridge Street and Brook Street.

The main carriageways were designed for a speed of 40 mph and to have a minimum radius of 1500 feet and maximum superelevation of 1 in 35. The maximum gradient was to be 1 in 25, and 1 in 19 on the intermediate ramps where the minimum radius was 109 feet, both made necessary by the need to accommodate the basic geometry of the existing ground level road network.

The bedrock is predominantly Bunter Sandstone of Triassic age, but over a short length adjacent to the West Manchester Fault the bedrock is Manchester Marl of Permian age. The rock is overlain by glacial drift varying in depth from about 8 to 47 feet, the depth being greatest near the middle of the alignment.

The standard foundation consists of two reinforced concrete bored piles and a linking pile cap under each column. The two piles, placed transversely to the main centre line of the structure, provide a 'couple' to resist the high lateral moments due to eccentric live loading, bearing restraint, centrifugal and wind forces, while the smaller longitudinal moments from friction are counteracted by the piles in bending. The piles are between 3 feet and 4 feet 6 inches in diameter and are belled out in the solid sandstone bedrock. The maximum base diameter of 7 feet was used in the region of the West Manchester Fault, where the piles were founded in marl. Before each pile was cast the footing was visually inspected and in many cases in situ plate bearing tests made to confirm the suitability of the rock to withstand the design loading.

The reinforced concrete columns are of rectangular solid section, tapering on the longitudinal sides and vertical on the transverse faces. They are monolithic with the pile caps.

The main structural element is a hollow box spine beam with the top slab cantilivered out on both sides. Over 85% of the superstructure is constructed with precast concrete units of uniform cross section. The transition section between the two and three lane parts of the structure is formed with in-situ concrete, and includes the ramps which carry a single traffic lane.

In contrast to the Hammersmith Flyover, when three basic types of precast unit were used for the beams, cantilevers and deck slabs, the functions of all three were combined in a single unit. As a result, both the casting and erection were simpler and more economic.

The joints between the segments were of in-situ concrete of 3 inch nominal thickness to allow for irregularities in the casting of the units and some latitude in erection.

After positioning the units on staging and the completion of jointing, Freyssinet multi-strand prestressing cables were threaded through pre-formed ducts within the webs.

The extremities of the superstructure, including the intermediate ramps, are terminated in solid reinforced concrete end blocks which formed effective anchorages for the main prestressing cables.

An embossed copper waterproofing membrane was laid over the entire carriageway area followed by a 2¾ inch thick double layer of hot rolled asphalt surfacing.

The bridge over the River Medlock was constructed with a deck of standard precast prestressed beams spanning 38 feet 7 inches.

The eighteen pedestrian subways included in the scheme were designed as reinforced concrete box culverts with the walls finished in glazed tiles.

The second stage was opened to traffic in March 1967.

The traffic islands beneath the elevated section were extensively landscaped in order to provide attractive secluded rest areas for local residents. Areas flanking the road along its entire length received similar treatment.

The 'Mancunian Way' was officially opened by Mr Harold Wilson, on the 5th of May 1967, the second time a section of motorway in the Region had been opened by the Prime Minister in office.

In 1992 the Mancunian Way was extended with a new flyover at the A6, replacing the former roundabout and landscaped pedestrian footpaths. This 300 metre section is officially the A635(M) and is the shortest motorway in the UK.