Humber Bridge July 1981. With a centre span of and a total length of , the Humber Bridge was the longest single-span suspension bridge in the world for 17 years, until Japan's Akashi Kaikyō Bridge opened on 5 April 1998. The road-distance between Hull and Grimsby was reduced by nearly as a consequence of the bridge. The bridge's surface takes the form of a dual carriageway with a lower-level foot and cyclepath on both sides. There is a permanent speed limit on the full length of the bridge. Each tower consists of a pair of hollow vertical concrete columns, each tall and
Suspension bridge whereas wire strand cables can be formulated one by one in mid-air from a temporary walkway. Most suspension bridges have open truss structures to support the roadbed, particularly owing to the unfavorable effects of using plate girders, discovered from the Tacoma Narrows Bridge (1940) bridge collapse. In the 1960s, developments in bridge aerodynamics allowed the re-introduction of plate structures as shallow box girders, first seen on the Severn bridge built 1961-6. In the picture of the Yichang Bridge, note the very sharp entry edge and sloping undergirders in the suspension bridge shown. This enables this type of construction to be