The Silver Jubilee Bridge, "Runcorn-Widnes Bridge" or Runcorn Bridge crosses the River Mersey and the Manchester Ship Canal at Runcorn Gap between Runcorn and Widnes in Halton, England. It is a through arch bridge with a main arch span of 361 yards (330 m). It was opened in 1961 as a replacement for the Widnes-Runcorn Transporter Bridge, and was initially known simply as the Runcorn Bridge or Runcorn–Widnes Bridge. In 1975–77 it was widened, after which it was given its official name in honour of the Queen's Silver Jubilee. It carries the A533 road and a cantilevered footway. The bridge is recorded in the National Heritage List for England as a designated Grade II listed building.
Until 1868, when Runcorn Railway Bridge was opened, the only means of crossing the Mersey at or near Runcorn Gap were by fording or by ferry, with the lowest crossing of the river being the road bridge at Warrington. The first bridge to carry vehicular traffic across Runcorn Gap was the Widnes-Runcorn Transporter Bridge which opened in 1905. This was an inefficient means of transport and it had become inadequate for the amount of traffic using it before the outbreak of the Second World War. In 1946 the Ministry of Transport agreed that the transporter bridge should be replaced when sufficient funds were available. Mott, Hay and Anderson were appointed as consultant engineers.
The new bridge had to allow the passage of shipping along the Manchester Ship Canal. Many ideas were considered, including a new transporter bridge or a swing bridge. These were considered to be impractical and it was decided that the best solution was a high-level bridge upstream from the railway bridge. This would allow the least obstruction to shipping and would also be at the narrowest crossing point. The first plan for a high-level bridge was a truss bridge with three or five spans, giving an 8 yards (7 m) dual carriageway with a cycle track and footpaths. This was abandoned because it was too expensive, and because one of the piers would be too close to the wall of the ship canal. The next idea was for a suspension bridge with a span of 343 yards (314 m) between the main towers with an 8 yards (7 m) single carriageway and a 2-yard (2 m) footpath. However aerodynamic tests on models of the bridge showed that, while the bridge itself would be stable, the presence of the adjacent railway bridge would cause severe oscillation.
The finally accepted design was for a steel through arch bridge with a 10-yard (9 m) single carriageway. The design of the bridge is similar to that of Sydney Harbour Bridge but differs from it in that the side spans are continuous with the main span rather than being separate from them. This design feature was necessary to avoid the problem of oscillation due to the railway bridge. The main span measures 361 yards (330 m) and each side span is 83 yards (76 m).
Construction began on 25 April 1956. The contractors for the first phase of work, Leonard Fairclough of Adlington, cleared the ground and constructed the foundations for the piers. The contract for the second phase, the building of the main arch and the side arches, was given to Dorman Long of Middlesbrough who sub-contracted the building of the bridge deck, viaduct and roadworks to Leonard Fairclough. Building of the bridge itself began in March 1958 and the side spans were completed by November 1959. The main arch was built by cantilevering steelwork from the side spans until it met in the middle in November 1960. The carriageway was suspended from the arch by 48 lock-coil wire ropes. From February 1960, approach roads and viaducts were being built on both sides of the river; the total length of viaduct constructed was 525 yards (480 m). The approaches on the Runcorn side blocked the Bridgewater Canal at Waterloo Bridge and the line of locks leading down to the Mersey were filled in. The bridge was officially opened on 21 July 1961 by Princess Alexandra.