Forth Road Bridge—maintenance and remedial works

Forth Road Bridge is a suspension bridge with a main span of 1006 metres and side spans of some 408 metres. Approach viaducts to the north and south bring the total length of the structure to just under 2500 metres. The bridge crosses the Firth of Forth some 16 km to the north and west of Edinburgh and was opened in 1964. Traffic has grown significantly from 4 million vehicles using the crossing during its first year of operation to the 24 million vehicles using the bridge last year. This paper lists major projects that have been carried out to strengthen and improve the structure and replace major components and makes reference to continuing major maintenance schemes such as bridge painting and resurfacing. The discovery of significant corrosion in the main cables has resulted in the implementation of a dehumidification scheme to halt or slow down the deterioration and this scheme is described. The preliminary findings of a study to examine the feasibility of replacing or augmenting the main cables and to investigate the long term structural integrity of the anchorages are also detailed.