Painting of the Forth Bridge - the paint job that famously "never ends" - is coming soon to an end.
After 10 years and an investment of over £130m, the scaffolding is coming off the 121-year old bridge, with a full paint job unlikely to be required again for over twenty years.
Balfour Beatty, who are under contract to Network Rail, expect to complete the paint-job "ahead of schedule" on Friday 9 December 2011. A celebration event to mark the end of the refurbishment will take place in March 2012.
The 2,467 metre Forth Bridge, also known as the Forth Rail Bridge, was completed in 1890 as part of an unbroken East Coast railway route from London to Aberdeen. It is reckoned that at the height of its construction more than 4,000 men were employed. There were 57 lives lost.
The bridge still carries around 200 trains a day. However, with 230,000m² of steel requiring paint, and 6.5 million rivet heads requiring painting by hand, it was often said that by the time the job of painting the bridge had finished it was time to start all over again.
The colloquial expression "like painting the Forth Bridge" was so ubiquitious that it even earned an entry in The Cambridge International Dictionary of Idioms.
The entry read: "If repairing or improving something is like painting the Forth Bridge, it takes such a long time that by the time you have finished doing it, you have to start again. ‘Home improvements are a bit like painting the Forth Bridge. By the time you've finished the kitchen, the bathroom needs decorating and so it goes on."
The expression may need a little update now. The bridge's latest paint job uses a specialist glass flake epoxy paint, supplied by WJ.Leigh of Bolton, similar to that used in the offshore oil industry. It is designed to last 25 years or longer.
"Over the last decade, the bridge has been restored to its original condition and its new paint will preserve the steelwork for decades to come," says David Simpson, route managing director, Network Rail Scotland. “We expect it to last in excess of twenty years but we will be back from time to time to maintain the most exposed sections of the structure.”
Before applying the new paint, 120 years worth of previous paint jobs is removed using an abrasive blasting preparation. The steel is coated with an industrial protective coating system and steelwork requiring maintenance is repaired before new paint is applied in three protective layers, both by airless spray and by hand in areas of particularly difficult access.
Marshall Scott, managing director, Balfour Beatty Regional Civil Engineering, said:
“The now fully restored Forth Bridge will continue to operate for many decades to come and it will provide the world renowned image that Scotland can be rightfully proud.
“The work that Balfour Beatty Regional Civil Engineering has provided to restore the Forth Bridge back to its original condition will remain as part of a legacy and a testament to the skills and expertise of those who built this much treasured structure more than a century ago.”
Forth Bridge Stats
- Length of Bridge (total): 2,467 metres
- Length of main structure (portal to portal): 1,630 metres
- Height - High water to top: 110 metres
- Height - Foundation to top: 137 metres
- Weight of steel in bridge: 53,000 tonnes
- Number of rivets: 6.5 million
- Concrete and masonry in piers: 120,000 cubic yards faced with 2ft thick granite
- Number of trains per day: 200 trains (3 million passengers)
- Painting area: 230,000 sq metres
- Volume of paint used: 240,000 litres
- Total number of lights installed: 1040 lights
- Length of cabling required: 35,000 – 40,000 metres
- 1873 Thomas Bouch’s first design for a suspension bridge across the Forth presented
- 1879 Bouch’s design for the Forth Bridge abandoned following Tay Bridge disaster
- 1882 Design submitted by John Fowler and Benjamin Baker approved
- 1883 Construction of Fowler and Baker’s cantilever structure began
- 1885 Last caisson launched
- 1886 Pier foundations completed
- 1887 Three towers completed
- 1889 Cantilevers completed
- 1890 Bridge formally opened by Prince of Wales on 4 March