Wye Bridge (M48 Viaduct)

Cadw's description

Location

Carries the M4 motorway over the Wye estuary and Beachley peninsula, as the western continuation of the Severn Bridge.

History

The Ministry of Transport adopted proposals for the Severn and Wye crossings under the 1945 Trunk Roads Act. Early designs were ready by 1950, but were later modified. Construction work did not begin until 1961 and was not completed until 1966. The engineers for the combined crossings were Freeman Fox and Partners, with Mott, Hay and Anderson; Percy Thomas was consulting architect, and the Cleveland Bridge and Engineering Company the contractors. The Wye Viaduct was one of the first cable stayed bridges to be built in England or Wales since 1918, and with the Severn Bridge, the first bridge in the world to have an aerodynamically shaped deck. It is also one of the earliest bridges of its type anywhere to use cables in only a single plane (a system developed in Germany). The structure was strengthened in 1987 (Flint and Neill, engineers), when the masts were increased in height to accommodate double the original number of cables.

Exterior

Cable-stayed bridge crossing the River Wye, continuing on piers over Beachley peninsula. Overall length 1153m, of which 408m is the Wye crossing with a main span of 234m, and two side spans. Streamlined continuously welded steel torsional box construction deck, stayed over the river crossing by steel cable ties in a single plane on the centre-line of the bridge, carried by a pair of steel masts above piers. Each mast carries two sets of cables (but originally only one). Open hand rails and stretched steel wire crash barriers. Slender, splayed inverted-U concrete piers on concrete beam foundations.

The eastern parts of the bridge, including its extension over Beachley peninsula are in England (Tidenham parish, Forest of Dean District).

Reason for designation

Listed as a fine example of a cable-stayed bridge of innovative design. It forms part of a group with the Severn Bridge.