THE firm behind the project to carry out repair works to the Forth Road Bridge following a fracture that caused the closure of the structure has said the “hugely challenging” project has been delivered.

A team from Spencer Group carried out works to replace
truss end links which connect the bridge deck to the towers.

The project had its origins in the discovery, in December 2015, of a fault on the crossing when immediate repairs were completed.

At a media conference at the time, engineers said that a 20mm-wide crack in a truss under the southbound carriageway close to the bridge’s north tower could not have been predicted and happened quickly.

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One of the eight truss end links on the bridge was found to have fractured, causing the bridge to be closed completely for more than three weeks while urgent repairs were carried out.

HeraldScotland:

A temporary splint was applied to the fractured link, followed by a permanent structural repair to that area.

Bridge owner Transport Scotland then moved to replace the other seven key links and Spencer Group were chosen in the tender process.

The £10 million scheme has involved cutting out the truss end links and replacing them with a unique new sliding bearing system.

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Gary Thornton, Spencer Group managing director, said: “The project showcased the expertise we bring to works such as this, which pose a range of major challenges. The solutions we put in place ensured critical components were replaced without having to interrupt traffic flows at any time.”

HeraldScotland:

Spencer said the project posed multiple challenges, with the team working in confined spaces within the main towers and manoeuvring large new structural components to precise tolerances.

The replacement bearings were delivered to the bridge from a workboat, so the works had to be co-ordinated with tide times within the busy Forth estuary.

Ensuring effective communication via two-way radios was crucial, with engineers working below the bridge deck having to contend with significant noise and vibration as traffic passed above them, it said.

HeraldScotland:

Project Manager Robbie Ryan looks up towards platforms below the bridge deck which the Spencer Group team installed to allow access to replace the truss end links which connect the bridge deck to the towers.

Spencer Group said its team delivered the project “successfully with minimal impact on normal bridge operations and with traffic flowing throughout”. It fabricated 200 tonnes of new steel and joined it to the existing structure.

The firm's schemes include the world’s largest project to dehumidify existing bridge cables, on Denmark’s Great Belt crossing.