Dedication and physical effort displayed by all those who designed...
Client: Network Rail. Designer: Pell Frishmann Consulting Engineers Ltd Contractor: Balfour Beatty Civil Engineering Limited
This Award recognises the teamwork, dedication and physical effort displayed by all those who designed and executed the work to restore this truly iconic structure using ground breaking techniques and methods.
About the project
This project has put an end to the well used description of the never ending job being like painting the Forth Bridge. Painting the bridge had indeed, been a never ending job until new Health and Safety legislation in 1974 ended the traditional means of carrying out the work. While the bridge structure was in a satisfactory condition it was essential that a maintenance regime was put in place to maintain its integrity while 200 trains a day passed across the bridge.
There were three strands to the work required. Firstly, safe access systems had to be provided; then, any corroded steel had to be replaced; and finally all the existing paint had to be removed and recoated with a high tech three part paint system.
The access works consisted mainly of complex and extremely robust scaffolding which was then encapsulated in sheeting to form working areas giving access to every corner of the bridge structure. As well as the load from up to 4,000 tonnes of scaffolding the wind loading on the bridge from these encapsulated areas was calculated for winds of 100 mph.
The encapsulation that many people would have seen, was ground breaking and utilised a heat sealed membrane wrapped around scaffolding to allow climatically controlled conditions to be created while allowing light to penetrate. This encapsulation process has since been adopted throughout the UK and has attracted attention from companies operating throughout the world.
The next work was to replace corroded steel and of the 53,000 tonnes of steel in the bridge only 200 tonnes had to be replaced. Grit blasting and painting followed with the first coat applied no later than four hours after cleaning the steel. The paint system was developed specially for the bridge and was based on North Sea oil industry technology being guaranteed to last for at least 20 years.
Logistically, the only time possession could be given to move material on to the bridge was early on Sunday mornings when up to 120 tonnes of equipment could be moved into position for the following week’s work. If material was not in the correct place during that period then it wasn’t a few minutes of time that would be lost - it would be a whole week.
One closure in the entire ten year period was inevitable to work on the diagonal members immediately above the track. This took eight days and during this time all scaffolding and encapsulation was erected; steel in the area grit blasted and painted; and the temporary works removed. This was the only closure of the bridge in its 122 year history.
In all, 1500 personnel worked over 4.5 million man hours on the £130m project over 10 years with as many as 400 tradesmen being employed at its peak.
Not only does the project leave a legacy of the Bridge, protected for at least the next 20 years, but memorials were erected near the North and South abutments as poignant reminders naming the workers that lost their lives in the construction of the Bridge in the late 19th Century. The youngest named is David Clark [13] Rivet Catcher. Regrettably there was one fatality in the present project which deeply affected the close knit community of the whole team but a Fatal Accident Inquiry concluded that the circumstances could not be accounted for and that no-one could have done more to prevent the accident.