Drying-out of bridge cables under way

Published on Friday 23 October 2009 10:13

THE process of drying out the corroded main cables on the Forth Road Bridge is underway after the installation of a dehumidification system was completed.

Campaigners hope the work could see the bridge last for another 80 years and avoid the need to build the 2 billion replacement crossing.

The bridge's chief engineer, Barry Colford, has said the cables will "almost certainly" need to be monitored for the remainder of their service.

Mr Colford also said there would always be some degree of uncertainty as to how much more strength the cables would lose over time.

The dehumidification system aims to prevent further loss of strength in the cables by reducing the relative humidity inside them to a level where corrosion cannot occur.

Work began in April 2006, using specially designed platforms to move up and down the cables and wrap them in a watertight and airtight membrane.

Dehumidification equipment was then installed to blow very dry air into the spaces between the 11,618 individual steel wires that make up each main cable.

Corrosion in the main cables was discovered during the first internal inspection of the cables in 2004.