Newly published engineering records confirm a major programme of steelwork strengthening on Scotland’s 62-year-old suspension bridge, alongside the replacement of original tower bearings, renewed cable monitoring and further structural repairs. The evidence also reveals how modern engineering has reduced the amount of reinforcement considered necessary.
The Forth Road Bridge is undergoing structural strengthening at 192 locations after engineers identified longstanding excessive stress in parts of the steel framework supporting its suspended roadway.
Newly published minutes of the Forth Bridges Forum confirm that the bridge’s upper structural chord has been subject to excessive stress for decades, prompting work to strengthen its connections and address elements considered below the required standard.
The disclosure appears in records of the forum’s 21 July meeting, published by Transport Scotland on 9 November. A separate engineering programme identifies 192 locations across the bridge where the top-chord splice plates are to be refurbished and strengthened.
The work forms part of a wider programme involving the replacement of original tower bearings more than 60 years old, repairs to supporting steelwork, improvements to maintenance access and renewal of the monitoring equipment used to detect possible deterioration in the main suspension cables.
New traffic management arrangements also begin this week. Traffic Scotland has scheduled daytime lane closures in both directions between 11 and 24 November for structural repairs, including working periods on 11, 12, 16 and 17 November.
The newly disclosed structural concerns do not establish that the bridge is unsafe or in danger of imminent failure. In engineering assessments, excessive stress can indicate that a component does not satisfy a particular design or assessment limit under specified loading conditions, rather than that it has physically fractured.
Nevertheless, the extent of the work illustrates the engineering demands involved in maintaining one of Scotland’s most important transport structures.
Opened in 1964, the bridge now carries buses, taxis, permitted non-motorway traffic, cyclists and pedestrians. It also retains an important contingency role should the neighbouring Queensferry Crossing become unavailable.
An examination of engineering reports dating back to 2008, procurement records, recent bridge inspections and the latest maintenance programme shows that the structural work is part of a continuing effort to extend the life of a bridge that has already undergone extensive reinforcement and repairs.
What Engineers Have Identified
At the July meeting, Barry Stewart of BEAR Scotland, the contractor responsible for operating and maintaining the Forth Road Bridge on behalf of Transport Scotland, provided an update on the structure.
The minutes record that the top chord had experienced excessive stress for decades and that strengthening was underway to address the condition and remove substandard elements.
The work was also described as necessary before any future increase in the height of the bridge’s parapets.
The top chord forms part of the steel stiffening truss beneath the bridge deck.
Although the Forth Road Bridge is a suspension bridge, with its principal loads carried by enormous cables passing over two towers, the deck also relies on a substantial system of steel girders and bracing.
The stiffening truss distributes forces created by traffic, wind and the weight of the structure.
Its upper and lower chords are connected by vertical and diagonal members, forming a framework that helps the deck resist deformation and transmit loads to the suspension system.
The chords contain joints where individual lengths of steelwork meet. These connections use splice plates and bolts to transfer forces between adjoining sections.
Transport Scotland’s environmental assessment for the 2026–27 maintenance programme specifies strengthening and refurbishment of top-chord splice plates at 192 locations across the bridge.
The figure identifies the scope of the planned work. It does not mean that 192 separate fractures have been found, or that every location has suffered the same degree of deterioration.
The published documents do not provide a location-by-location breakdown of defects or identify how many connections have already been strengthened.
That distinction matters because the latest records describe an engineering programme addressing known structural stresses, not the discovery of 192 new failures.
Engineers Were Investigating the Stress Nearly Two Decades Ago
The concerns identified in the latest minutes have a substantial history.
A detailed assessment prepared for the former Forth Estuary Transport Authority by W.A. Fairhurst & Partners in March 2008 examined the bridge’s steel stiffening truss and its performance under different combinations of traffic, wind and permanent structural loading.
The report followed earlier investigations, including assessments undertaken during the 1980s and 1990s.
It examined the upper and lower chords, diagonal and vertical members, lateral bracing, cross girders, splice plates and bolts.
Engineers calculated how the structure would respond under a range of specified loading conditions, including standard highway assessment loads and reduced loads reflecting operational restrictions.
The assessment identified elements whose calculated stresses exceeded the relevant limits.
The findings included concerns about the steel plates and bolted joints connecting sections of the truss chords.
In several instances, the report identified differences between the performance of connections under full standard loading and under the lower loading assumptions used for the bridge’s actual operating arrangements.
The analysis also found that some top-chord connections were more vulnerable to particular loading conditions because of the configuration of their cover plates and bolts.
A structural assessment of this kind does not necessarily demonstrate that the bridge was carrying loads beyond its immediate physical capacity.
The calculations use engineering standards, safety factors and specified combinations of traffic and weather conditions to determine whether elements meet required performance criteria.
However, identifying connections that do not satisfy those criteria gives engineers a basis for prioritising further examination, strengthening or changes to operating arrangements.
The 2008 report therefore provides important historical context for the latest work.
It establishes that concern about the truss and its connections predates both the present maintenance programme and the structural failure that temporarily closed the bridge in 2015.
The outstanding question is how the current strengthening programme relates to the specific deficiencies identified in earlier assessments, and which locations still require intervention.
The 2015 Failure Changed the Way the Bridge Was Managed
The most serious recent event in the bridge’s history occurred in December 2015.
During a routine inspection, engineers discovered a fracture in a truss end link near the northern tower.
The link formed part of the mechanism supporting the suspended deck where it meets the tower.
Further examination revealed significant damage, and the bridge was closed to traffic for more than three weeks.
The closure disrupted journeys between Edinburgh, Fife and destinations farther north, demonstrating the economic importance of the crossing.
Temporary steel repairs allowed most traffic to return before Christmas, while further work continued into 2016 to restore access for heavy vehicles.
The eventual investigation established that a pin in the truss end-link mechanism had seized, preventing the movement for which the component had been designed.
That restriction caused stress to accumulate in the adjoining steelwork.
A Scottish Parliament inquiry concluded that the failure could not reasonably have been predicted through the inspection arrangements then in place.
The inquiry also examined the procedures for deciding when a bridge should be closed, following concerns about the time taken between engineers recommending closure and the decision being implemented.
A permanent engineering solution followed.
Between 2016 and 2019, the original truss end links were replaced with a new sliding-bearing arrangement designed to accommodate the necessary structural movement.
The replacement programme cost approximately £10 million.
The 2015 fracture involved a different component from the top-chord splice plates included in the current programme. The published evidence does not establish that the failures or stresses share a common cause.
Its lasting significance was the development of a more comprehensive approach to assessing and monitoring critical parts of the bridge.
Transport Scotland’s Critical Elements Programme was established following the failure, using structural inspections, engineering analysis and continuous monitoring to prioritise work.
The latest strengthening programme sits within that broader approach to managing the risks associated with an ageing structure.
Modern Analysis Has Reduced Some Strengthening Requirements
One of the more important developments in the bridge’s engineering history is that newer assessment techniques have reduced the amount of reinforcement previously considered necessary.
Engineering consultancy COWI, working as an independent checker for BEAR Scotland on behalf of Transport Scotland, undertook a reassessment of wind-related loading on parts of the bridge.
The work combined detailed wind-tunnel research with satellite-based positioning measurements collected during eight significant storms between 2021 and 2023.
The purpose was to establish how the bridge actually behaved under strong winds, rather than relying entirely on theoretical estimates.
The analysis indicated that forces and movements within some structural members were lower than earlier assessments had predicted.
COWI reported that the number of top lateral bracing members assessed as overstressed fell from 184 to eight.
As a result, more than 120 tonnes of proposed reinforcing steelwork was no longer considered necessary.
The consultancy estimated that this avoided approximately 240 tonnes of embodied carbon dioxide equivalent.
This is a significant finding, but it concerns a different element of the bridge’s strengthening programme.
The 184 top lateral members examined in the wind reassessment are not the same as the 192 top-chord splice-plate locations identified in Transport Scotland’s current maintenance documentation.
The figures must not be confused or subtracted from each other.
The reassessment demonstrates that more detailed monitoring and analysis can identify places where reinforcement is unnecessary, reducing costs, construction activity and the environmental impact of repairs.
It also illustrates the importance of revisiting engineering assumptions as better evidence becomes available.
The present 192-location programme should therefore be understood alongside the wider process of reviewing which parts of the bridge require strengthening and which can continue operating without additional steelwork.
Original Tower Bearings Are Being Replaced
The top-chord work is only one part of the programme.
The July meeting also reported continuing replacement of the bridge’s main tower lateral thrust bearings.
These components have remained in service for more than six decades.
Lateral thrust bearings help transfer sideways forces between parts of the suspended structure and its towers, including forces generated by wind.
They must accommodate the movement and loading characteristics of a suspension bridge while helping maintain the intended structural alignment.
Replacing them is technically demanding because the work takes place within a complex structure that remains in use.
It involves strengthening adjacent steelwork, installing replacement components, providing safe access and protecting exposed surfaces against corrosion.
A public presentation by BEAR Scotland in January 2026 valued the bearing replacement and associated strengthening, painting and access works at approximately £3 million.
That figure relates to the bearing project and associated work. It is not the total cost of the bridge’s wider strengthening programme or the 192 splice-plate locations.
The January presentation indicated that the bearing work was expected to finish in September 2026.
However, the July forum minutes described work extending across 2026 and 2027, while BEAR Scotland’s latest progress statement, issued on 10 November, still referred to preparations for replacing critical lateral thrust bearings.
Those documents do not establish whether the original timetable has formally changed, whether individual stages have been completed or whether outstanding work is being undertaken under an extended programme.
Clarification of the current completion date and expenditure would provide a more accurate account of the project’s progress.
Main Suspension Cables Have Also Been Inspected
The bridge’s two principal suspension cables are among its most important structural elements.
Each cable measures approximately 590 millimetres in diameter and contains 11,618 high-tensile steel wires.
Their condition is fundamental to the long-term future of the crossing.
Corrosion inside suspension cables presents a particular engineering challenge because deterioration can develop between individual wires, beyond the reach of ordinary external inspection.
The Forth Road Bridge has an extensive history of addressing that problem.
In the 1990s, deterioration was identified in suspension components, prompting a programme to replace the vertical hanger ropes connecting the deck to the main cables.
The hangers were replaced between 1998 and 2000.
Later investigations established concerns about the internal condition of the main cables themselves.
Engineers introduced a dehumidification system in 2008, designed to circulate dry air through the cable assemblies and reduce the moisture responsible for corrosion.
The system was subsequently upgraded.
At the January 2026 public meeting, BEAR Scotland reported positive findings from internal cable inspections.
Its presentation stated that no further deterioration had been identified in the particular cable panels reinspected in 2004, 2008, 2018 and 2025.
That is encouraging evidence, although it should not be interpreted as establishing that every wire throughout both cables is free from deterioration.
The bridge operator also reported that, with appropriate continuing maintenance investment, the main cables were expected to fulfil their intended service life of at least 120 years.
That is an engineering expectation dependent on future inspection and maintenance, not a guarantee that the entire bridge can remain in service for that period without substantial additional work.
The latest maintenance programme includes replacement of the acoustic monitoring system used on the main suspension cables.
This equipment is intended to help identify potential wire failures by detecting characteristic sounds within the cable assemblies.
A report published by the Institution of Civil Engineers in January 2025 described acoustic monitoring as a central part of the bridge’s structural health programme.
It also recorded that the bridge had 238 structural monitoring sensors concentrated around critical locations, including the truss ends, towers and anchorages.
These systems provide engineers with continuous data about structural movement, temperature, strain and other conditions.
However, monitoring does not itself repair defective components. Its value lies in providing evidence that can inform inspection, maintenance and decisions about continued operation.
Eight Major Maintenance Schemes Are Identified
Transport Scotland’s 2026–27 environmental record identifies eight areas of work on the Forth Road Bridge.
They extend beyond the visible steelwork strengthening.
The programme includes refurbishment of the main tower bearings, continued improvements to the suspended-span access system, strengthening and repairs to approach viaduct box girders, and resurfacing and concrete repairs to footways.
It also covers replacement of footway bearings, refurbishment of vehicle restraint barriers and their supporting steelwork, renewal of the main-cable acoustic monitoring system, and the 192-location top-chord strengthening scheme.
Some of this work addresses structural capacity and movement.
Other elements concern corrosion protection, safe access for future inspections, the condition of pedestrian and cycle facilities and the preservation of equipment that has been exposed to the marine environment for decades.
Work on the viaduct box girders includes drainage refurbishment, sealing gaps and repainting internal steelwork.
Transport Scotland has also identified the removal of remaining lead-based paint systems as part of its refurbishment objectives.
The suspended-span under-deck access system is another important part of the programme.
The bridge was built at a time when permanent access for maintenance and inspection was less sophisticated than modern standards.
Retrofitting access platforms and walkways allows engineers to inspect and repair areas that would otherwise be exceptionally difficult to reach.
The Institution of Civil Engineers has identified accessibility as a continuing challenge for the structure.
Improving that access can reduce the cost and disruption associated with future repairs, although it requires substantial engineering work in its own right.
The environmental record anticipates that the work will be undertaken mainly during daytime hours, with occasional night working where temporary structures or traffic management need to be installed or removed.
The programme includes the possibility of full carriageway, individual lane and footway closures where required.
Further Structural Lane Restrictions Begin This Week
The effects of the maintenance programme are already being experienced by bridge users.
Traffic Scotland has scheduled outside-lane closures in both directions on the A9000 Forth Road Bridge between 11 and 24 November for structural repairs.
The published arrangements identify daytime working periods on 11, 12, 16 and 17 November, with a temporary 30mph restriction where the traffic management is operating.
The published date range should not be taken to mean that every lane will remain closed continuously throughout the two weeks.
The latest notices also do not identify which of the individual strengthening projects is responsible for each closure.
Earlier in the year, BEAR Scotland introduced lane restrictions and overnight closures to accommodate refurbishment of the bridge’s central grillage.
Those works began in late June, with single-lane restrictions originally expected to remain until the end of October.
The July forum minutes also recorded that the west footway was being used for maintenance plant and equipment.
The Forth Bridges’ current public information continues to identify the west footway as closed, while the east footway remains the normal route for pedestrians and cyclists.
The forum was told that working arrangements could be reversed during a later phase, with maintenance activity moving to the opposite footway.
Changes of this kind are important because the Forth Road Bridge provides the principal walking and cycling crossing at Queensferry.
The neighbouring Queensferry Crossing is designated as a motorway and does not provide an ordinary pedestrian or cycle route.
The older bridge’s continuing operation therefore serves transport needs that cannot simply be transferred to its replacement.
Why the Old Bridge Still Matters
The opening of the Queensferry Crossing in 2017 fundamentally changed the Forth Road Bridge’s role.
For more than five decades, the suspension bridge had carried general road traffic between Fife and Edinburgh.
Traffic growth greatly exceeded its early operating assumptions.
The Institution of Civil Engineers reported that annual crossings increased from approximately four million to a peak of 24 million, while maximum lorry loads rose from 24 tonnes to 44 tonnes.
The cumulative effect of heavier vehicles, greater traffic volumes and a corrosive marine environment created significant maintenance demands.
The new Queensferry Crossing took over the principal motorway function, allowing general cars and heavy goods vehicles to use a separate bridge designed for modern traffic loads.
The Forth Road Bridge became a public transport corridor, with continued access for buses, taxis, permitted vehicles, pedestrians and cyclists.
Removing the heaviest routine traffic reduced the demands placed on its ageing structure.
But it did not eliminate the need for inspection, strengthening or renewal.
The bridge also retains an important role as a temporary alternative for traffic if the Queensferry Crossing must be closed.
Automated barriers have been installed to facilitate diversions between the crossings.
These arrangements are designed to improve resilience and reduce the time needed to establish alternative traffic routes during incidents.
A 2025 test demonstrated that a diversion could be implemented in approximately 15 minutes.
The ability to use the older bridge during an emergency depends on appropriate traffic management and the bridge’s permitted loading arrangements.
The Institution of Civil Engineers concluded in 2025 that the Forth Road Bridge remained structurally capable of supporting full traffic loading as a temporary emergency measure.
That assessment provides important context for the latest maintenance records.
The bridge is not simply a redundant structure being preserved for historical reasons.
It remains part of Scotland’s working transport infrastructure, providing public transport access, active travel connections and contingency capacity across the Forth.
The Cost of Maintaining an Ageing Bridge
The scale of the work raises questions about the long-term cost of maintaining the Forth Road Bridge alongside the Queensferry Crossing.
The January presentation identified approximately £3 million for the lateral thrust bearing replacement and associated activities.
However, the public documents examined do not provide one consolidated cost for the eight maintenance schemes identified in the 2026–27 programme.
Nor do they identify the final contract value of the 192-location top-chord strengthening work.
The bridge’s wider financial history demonstrates that expenditure can vary considerably from one year to another.
The Institution of Civil Engineers reported maintenance expenditure of £20.7 million in 2017–18, compared with £6.3 million in 2023–24.
Those figures reflect different periods in the bridge’s maintenance programme and should not be interpreted as a like-for-like reduction in the underlying cost of keeping the structure in service.
Major repair projects can create peaks in expenditure, while structural inspections, monitoring and routine preservation continue between them.
BEAR Scotland’s most recent quarterly announcement, published on 10 November, reported more than £26 million of maintenance and improvement work across the entire South East trunk road network during July to September 2026.
That regional figure must not be confused with expenditure on the Forth Road Bridge alone.
The same announcement confirmed that the bridge’s strengthening, refurbishment and painting programmes had continued during the summer.
The latest documentation leaves several financial questions unanswered.
These include the current total budget for the top-chord works, the expenditure already committed, how the replacement of tower bearings is being phased and whether the remaining programme can be completed within existing allocations.
Without those figures, it is not possible to establish the total cost of the latest structural interventions or whether they have exceeded their original estimates.
What the New Records Establish
The Forth Road Bridge’s present engineering programme is the result of a long history of investigation and adaptation.
Structural assessments had identified excessive stress in parts of the stiffening truss well before the 2015 end-link failure.
That failure prompted a more comprehensive approach to managing critical components, supported by increasingly sophisticated monitoring.
More recent analysis has shown that some earlier strengthening proposals were more extensive than necessary, allowing engineers to reduce planned construction without compromising the performance required by their assessments.
At the same time, the present programme confirms that substantial work is still needed.
Strengthening is planned at 192 top-chord connection locations, original tower bearings are being replaced, and equipment used to inspect and monitor the bridge is being renewed.
The work is taking place while the crossing continues to support public transport, pedestrians, cyclists and emergency diversion arrangements.
The most important unanswered questions are the current completion status of the 192-location programme, how many connections have required substantial reinforcement, the revised schedule for bearing replacement and the full cost of the works.
Transport Scotland’s published minutes establish that the concerns are longstanding and that remedial work is underway.
They do not provide evidence of an immediate threat to bridge users.
For the Scottish Government, the long-term challenge is maintaining two major road crossings with different structural designs, traffic functions and maintenance requirements.
For engineers, it is ensuring that a bridge built in the early 1960s continues to operate safely while the cumulative effects of age, weather, corrosion and structural movement are properly managed.
The latest records demonstrate that the Forth Road Bridge’s future depends not on a single repair, but on continuing inspection, technically justified strengthening and sustained investment in the structure that remains an essential part of Scotland’s transport network.
Sources
Forth Bridges Forum — Meeting 58, Minutes, 21 July 2026. Transport Scotland. Published 9 November 2026.
https://www.transport.gov.scot/publication/forth-bridges-forum-meeting-58-minutes-21-july-2026/
Forth Bridges Forum — Meeting 57, Minutes, 21 April 2026. Transport Scotland. Published 9 November 2026.
https://www.transport.gov.scot/publication/forth-bridges-forum-meeting-57-minutes-21-april-2026/
A9000 Forth Road Bridge: Environmental Record of Determination — Project Details, 2026–27. Transport Scotland. 2026.
https://www.transport.gov.scot/publication/a9000-forth-road-bridge-environmental-record-of-determination/project-details/
Forth Road Bridge: Stiffening Truss Assessment Report. W.A. Fairhurst & Partners, for Forth Estuary Transport Authority. March 2008.
https://control.foi.theforthbridges.org/freedom-of-information-requests/truss-end-links/22-stiffening-truss-assessmehurst-report-march-2008/
A9000 Forth Road Bridge — Truss Chord Strengthening, Procurement Notice OCT542053. Public Contracts Scotland / BEAR Scotland. 24 October 2025.
https://www.publiccontractsscotland.gov.uk/search/show/search_view.aspx?ID=OCT542053
Forth Bridges Forum Public Meeting: Operational and Engineering Update. Transport Scotland / BEAR Scotland. 20 January 2026.
https://www.theforthbridges.org/media/qf2hxg5l/forth-bridges-forum-public-meeting-200126.pdf
Delivering for Scotland’s Trunk Roads: Summer Progress Across the South East Network. BEAR Scotland. 10 November 2026.
https://www.bearscot.com/delivering-for-scotlands-trunk-roads-summer-progress-across-the-south-east-network/
Work on Scotland’s Forth Road Bridge Saves 240 Metric Tons of CO₂e. COWI engineering assessment, reported by Structure Magazine. 2025.
https://www.structuremag.org/news-post/work-on-scotlands-forth-road-bridge-saves-240-metric-tons-of-co%E2%82%82e-on-scotlands-forth-road-bridge/
State of the Nation 2025: Infrastructure — Forth Road Bridge Case Study, Pages 14–19. Institution of Civil Engineers. January 2025.
https://www.ice.org.uk/media/4robmpno/ice-state-of-the-nation-2025.pdf
Forth Road Bridge Structural Repairs — Southbound Lane Restrictions, 11–24 November 2026. Traffic Scotland.
https://www.traffic.gov.scot/more-details?sid=pSEU202629090&type=proadworks
Forth Road Bridge Structural Repairs — Northbound Lane Restrictions, 11–24 November 2026. Traffic Scotland.
https://www.traffic.gov.scot/more-details?sid=cSEU202629091&type=roadworks
Forth Road Bridge Central Grillage Refurbishment. BEAR Scotland. 5 June 2026; updated 19 June.
https://www.bearscot.com/forth-road-bridge-central-grillage-refurbishment/
Truss End Links Repair — One Year On. Forth Bridges / BEAR Scotland. 19 December 2016.
https://www.theforthbridges.org/news-and-blogs-from-the-forth-bridges/truss-end-links-repair-one-year-on/
Scottish Parliament Official Report — Forth Road Bridge Closure Inquiry. Scottish Parliament. 15 March 2016.
https://www.parliament.scot/chamber-and-committees/official-report/search-what-was-said-in-parliament/meeting-of-parliament-15-03-2016?iob=96090&meeting=10437
Forth Bridges Special Project. Transport Scotland.
https://www.transport.gov.scot/transport-network/roads/forth-bridges-special-project/
Access Restrictions: Forth Road Bridge and Queensferry Crossing. Forth Bridges / Transport Scotland.
https://forthbridges-live.cssoftware.co.uk/plan-your-journey/road-user-guide/access-restrictions/
Forth Road Bridge — Structural Design and Engineering. Forth Bridges.
https://www.theforthbridges.org/about-the-forth-bridges/forth-road-bridge/about-the-forth-road-bridge/
