Suspended span under deck access
The Suspended Span Under Deck Access or SSUDA system is currently in the process of being upgraded.
The Forth Road Bridge has approximately 10km of under deck walkways, which engineering, maintenance and inspection teams use on a daily basis to carry our routine inspection and maintenance. These walkways which were installed in the early 1980s and are now in need of refurbishment to extend their life and improve their loading capacity.
Following the successful completion of Phase 1, which was undertaken earlier in 2017, Phase 2 works will be undertaken to replace components that have reached the end of their service life and increase the system's load carrying capacity.
In order to reduce the environmental impact of the project, the existing steelwork is being “upcycled” so that it can be reused and last for years to come.
This process involves the installation of a specially designed hanging scaffold which is suspended from the underside of the bridge deck. Once the scaffolding is complete, each of the steel elements is individually tagged and its location recorded to ensure correct placement after refurbishment. Once tagging has taken place the steel components are dismantled, then taken off the bridge and transported to a shot blasting facility.
Once at the shot blasting facility the existing coating along with any corrosion is cleaned off the surface of the steelwork using steel shot, which is fired towards the steel with high pressure air.
At this stage detailed inspections are carried out to determine the condition of the steelwork and its suitability for reuse.
Once cleaned and inspected, the steelwork is then dipped into molten zinc baths which provides a protective coating to the steelwork in a process known as galvanising before being transported back to the bridge. This zinc coating will protect the refurbished steel in the harsh marine environment for around 50 years.
Once back at the bridge, these steel elements are then re-fitted to the bridge using the tags to ensure correct positioning along with any other new sections of steel required to increase the walkways' loading capacity.
Based on results noted during Phase 1 it is anticipated that 97% of the existing steelwork will be reused during the works - significantly reducing the cost and environmental impact.
Works will be undertaken from both the East and West footpaths of the Forth Road Bridge from Autumn 2017 to Spring 2018.