Severn Bridge and Aust Viaduct First Severn Crossing

The Severn Bridge and Aust Viaduct, part of the First Severn Crossing, is a motorway bridge over the River Severn, built between 1961 and 1966. Designed by Freeman Fox and Partners in collaboration with Mott, Hay and Anderson, with consulting architect Sir Percy Thomas, the bridge features steel cables, a deck and towers, and a concrete substructure and foundation, including cable anchorages and piers for the towers. The viaduct structure is made of steel with a concrete deck slab.

The suspension bridge has a main span of 987.5 meters, flanked by two side spans of 305 meters each, and boasts an aerodynamically shaped deck with inclined hangers. It was the first bridge in the world to incorporate these innovative features and was the longest span in England at the time of its completion. The viaduct is 156.5 meters long and consists of three spans made up of two box girders working together with the concrete slab.

As part of the First Severn Crossing for the M48 motorway, which was formerly the M4, it includes the Aust Viaduct, Severn Bridge, and Wye Viaduct. The bridge underwent strengthening and refurbishment from 1985 to 1991, which did not significantly alter its appearance. Recently, it was repainted white to alleviate thermal stress, a change from its original color but deemed successful.