Humber Bridge main cable dehumidification and acoustic monitoring – The world's largest retrofitted systems

Abstract

When opened in 1981, the Humber Bridge became the world's longest span at 1410 m, a record it held for 17 years. Internal cable inspections of the two older major UK suspension bridges from 2004 to 2006 revealed unexpected levels of corrosion and broken wires. Following this discovery the Humber Bridge Board commissioned the development of a pro-active maintenance strategy which led to an internal inspection of the cables in 2009. Although only a few broken wires were found, there was extensive corrosion present which confirmed the need to minimize future deterioration and monitor the cable condition. A cable dehumidification system has been designed and installed on the bridge to prolong the life of the cables, and this sets new standards in terms of speed, quality and safety of the installation of the largest retrofitted system in the world. An acoustic monitoring system has also been installed which is the largest acoustic monitoring system currently fitted on a suspension bridge.