Humber Bridge: suppressing main cable corrosion by means of dehumidification

The Humber Bridge officially opened in 1981 and carries 4 lanes of traffic across the Humber Estuary between Barton and Hessle to the west of Kingston-upon-Hull in East Yorkshire, England. When opened, it was the longest span suspension bridge in the world with a main span of 1410m but it currently ranks as the fifth longest span in the world. Humber Bridge Board (HBB) commissioned an internal inspection of the main cables following the discovery of extensive corrosion and broken wires in the main cables of two older suspension bridges in the UK. The main cable inspections revealed widespread, if generally light corrosion with localised pitting and a very small number of broken wires. Dehumidification of suspension bridge main cables is becoming standard practice not only in the UK but worldwide. This paper examines the installation of the Humber Bridge system, discusses the mechanics of atmospheric steel corrosion and explains how the cable dehumidification system will suppress future corrosion.