Major repairs to the Forth Road Bridge connecting Edinburgh and Fife have been completed at a cost of £10 million. The project, carried out by bridge work specialists Spencer Group, followed the discovery of a fracture in one of the eight truss end links on the bridge in December 2015. This resulted in the closure of the bridge for almost a month. At this time a temporary splint was applied to the fractured link before a permanent repair was carried out.
Once this repair was completed bridge owners Transport Scotland decided to replace the other seven truss links, initiating a tender process which was won by Spencer Group, specialists in the complex engineering work required. It was to prove challenging work which involved cutting out the links and replacing them with a unique sliding bearing system.
A Challenging Project
One of the main challenges Spencer Group faced on the Forth Road Bridge was access. Temporary stairs and platforms had to be constructed to give access to below the bridge deck. Meanwhile, the replacement bearings were transported to the bridge by boat, having to take in to account the tides and the busy traffic on the waters of the Forth estuary. The engineers also had to work within the confined spaces of the towers and coordinate the manoeuvring of the large structural replacements to the necessary levels of precision required. Over 200 tons of fabricated steel have been added in some very difficult to access areas of the bridge, with weights of up to 16 tons being lifted in to place.
A Collaborative Approach
Despite the challenges faced on this project, Spencer Group were able to complete on time and with fairly minimal disruption to the normal traffic use of the bridge. The group’s bridges projects manager, James Barnes, highlighted the collaborative nature of the project and how important this was in devising solutions to complete the work safely. Transport Scotland was represented by Amey, who are the maintenance contractors for the Forth Road Bridge.
They reported a key factor for the repairs was finding a contractor with experience of working on long-span, cable-supported bridges, of which Spencer Group was just one of only a few companies with this experience. The technical aspects of this engineering task were exceptionally high, so a contractor with the relevant experience was imperative.
Modification for Future Work
Besides the replacement of the truss end links, Spencer Group made some modifications which included new, permanent stairs and platforms. These are designed to make any future maintenance or repair work easier to access. The Forth Road Bridge is not the only bridge in Scotland Spencer Group have been working on, having installed an under-deck gantry on the Erskine Bridge and a bespoke under-deck gantry on the Kessock Bridge, not far from Inverness. In England they are involved in essential maintenance work on the Humber Bridge, a part of the world they know well with the company headquarters based in Hull.