4 July 2007
The Forth road bridge was built in 1964 to link Edinburgh to Fife across the Firth of Forth, replacing the previous ferry crossing. It is located just upstream of the Forth rail bridge. The main span of the bridge is 1006 metres, still only one of two bridges in the UK with spans of over a kilometre. The bridge carried 2.5 million vehicles in its first year, but now carries around 12 million vehicles annually. Tolls on the bridge were abolished in 2008.
Although it was constructed only a couple of years before the Severn Bridge, the Forth bridge does not feature the revolutionary aerodynamic deck design seen in the later bridge and instead has a more traditional truss deck.
In 2003, an inspection discovered that 22 of the 11,000 steel suspension cables had snapped, possibly due to corrosion. (Similar failures have since been discovered, on a smaller scale, in the Severn Bridge.) It was feared that weight limits would have to be applied to vehicles crossing the bridge, and that it might eventually have to close entirely. Therefore the Scottish Government gave the go-ahead for a third bridge to be built across the Forth. This is to be a cable-stayed structure.
Repair works were subsequently carried out, including dehumidification of the suspension cables, and it is now thought that the weakening of the structure has been halted, leading to calls for the new bridge project to be scrapped. Current plans are for the original road bridge to become a dedicated public transport corridor.
The bridge was originally designed with a lifespan of 120 years. The rail bridge that runs alongside it celebrated its 120th anniversary in 2010.