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If you continue without changing your settings, we'll assume that you are happy to receive all cookies on The Forth Bridges website. However, you can change your cookie settings at any time. Toggle navigation. Home Forth Bridge History. History of the Forth Bridge A regular ferry operated between North and South Queensferry as far back as the 12th century. Forth Bridge. Facts and figures. The bridge builders. Construction statistics.
Building the bridge. Growth and milestones. The total length of the bridge, including its approach viaducts is 2, metres. The main structure itself measures 1, metres portal to portal. It incorporated 6. It was designed to withstand a wind force of 56lb per square foot. Building the foundations for the vast towers started with the construction of huge caissons which were built on site and sunk using compressed air.
The first of the caissons was floated into position on 26 May By all the foundations were in position ready to take the steelwork. Thanks to the organisation and inventiveness of William Arrol, the bridge was completed in November , just 6 years after work started although at the time the weather was particularly cold and Arrol had to wait for milder weather conditions before the enormous structure expanded sufficiently for the final rivets to be inserted.
After all testing and inspections of the bridge were completed, it was formally opened by the Prince of Wales later King Edward VII , who drove home a final gold plated rivet, on 4 March The cantilevers are supported by granite piers. The river bed at the south cantilever, which is 91ft below the high-water level, made use of compressed air to stop water pouring into the working chamber at the base, while the other cantilevers were constructed using caissons measuring 70ft in diameter.
Foundations were constructed using cylinders, which were lowered using sandbags. Working chambers were created to pump compressed air, whereas airlocks and airshafts provided access for men and materials.
Bridge construction was carried in two phases. The first phase, carried out from to , involved works on the substructure, including sinking the caissons and constructing the foundations and piers to support the superstructure.
The superstructure, which weighs approximately 51,t, was built from to Altogether, the construction of the bridge made use of 53,t of steel, 20, cubic metres m 3 of granite, 6,m 3 of stone, 49,m 3 of concrete, 50t of cement and 6. At the peak of construction, more than 4, workers were associated with building the railway bridge.
The painting work on the Forth Rail Bridge was completed in December and is expected to last for 25 years. Railtrack gave up the refurbishment contract in due to financial reasons. Under the ten year project, Balfour Beatty carried out the refurbishment works, which included the repair of the steels, coating of the surface, improvements to the access of the bridge and upgrade of the flood lightings.
The company used a method of blasting the old layers of paint which enabled the steel to be repaired. Zinc-based primer of 35 microns was used to prevent corrosion and microns of glass flake epoxy intermediate coating was used to act as a barrier, after which 35 microns of polyurethane gloss top coat was used to provide the finishing touches.
The work involved up to 1, people at its peak, with an average of people working on the bridge daily. Balfour Beatty used Pyeroy for the painting work and Harsco Infrastructure for the scaffolding work.
Scaffolding work included enclosing the bridge in up to 4,t of scaffolding by reversing the established ground-up approach. The access platforms were enclosed in plastic sheeting to avoid paint being blasted into the environment and to protect the glass flake paints while drying. The painting work was done by shot-blasting the previous paint layers and applying primer, glass flake and polyurethane coatings.
Vital was appointed as the subcontractor for the automated track warning system ATWS , safety maintenance, support and safety road rail vehicles RRVs.
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