Which one?
There are 2 and one is much longer than the other!
Original Severn Bridge:
The Severn Bridge was opened by the Queen on the 8th September 1966 to replace the ferry service crossing from Aust Cliff to Beachley Peninsula, 8 miles upstream from Avonmouth. At this point the River Severn is almost exactly 1 mile wide at high water and the bridge creates a direct link for the M4 motorway into Wales.
The Severn Bridge is in fact two bridges. The main section spans the Severn Estuary, whilst the second smaller section spans the River Wye.
The Severn Bridge
Main Span3,240 ft
Distance Apart, c. to c. of cables75 ft
Side Spans, each1,000 ft
Level of tops of towers445 ft O.D.
Sag span ratio of cables1/12
Second Severn Crossing:
Overall length of Crossing Structure5,128m
Length of Shoots Bridge948m
Length of Main Span456m
Navigation Clearance37m
Length of Welsh approach Viaduct2,077m
Length of English Approach Viaduct2,103m
Height of Main Span Pylon Towers137m
Number of Approach Spans - Welsh Side24
Number of Approach Spans - English Side25
Maximum height of Approach Piers48m
Number of foundations in Caissons37
Total volume of concrete required320,000m cubic
Weight of reinforcing steal30,000 tons
Total length of pre-stressing steel150,000m
Number of Stay Cables In Shoots Bridge240
Total number of Concrete Deck Units2,434
Approximate number of men employed1000
Construction Period1992 to 1996