Closure of Cardross Bridge as major works start on 250-year-old crossing

Extensive improvement works are set to begin at Cardross Bridge and secure the future of the 18^th century river crossing.

Investment of £1.2m has been made by Stirling Council to repair and strengthen the Category B Listed bridge, which carries the B8034 over the River Forth between Arnprior and Port of Menteith.

The work will necessitate a full road closure of the B8034 for six months from Monday 9 September 2024, with a diversion route in place via Thornhill.

A written update on site progress will be issued to affected community councils on a regular basis, with a series of business and community engagement events also scheduled in advance of the work and as it progresses. 

The project, which required Listed Building Consent, is part of Stirling Council’s £6.6 million investment in its road network this year.

It is one of 72 projects taking place across the Stirling area as part of the council’s commitment to maintain and upgrade its vast road and footway network that stretches more than 1,000 km. And it comes on the back of the council completing works to Blane Water Bridge on the B834 ahead of schedule.

Contractors will remove and rebuild the bridge walls and undertake a full repointing of the stone using traditional materials. Cracks will also be repaired, with works to protect the bridge from river erosion, as well as the installation of a new bridge deck. The bridge will have a 10-ton weight limit when completed.

Cllr Jen Preston, convener of the Environment, Transport and Net Zero Committee, said: “The condition of the structure of Cardross Bridge has deteriorated in recent years and subsequent investigations and surveys have clarified the necessity for these works.

“The bridge dates back to 1774 and it will be repaired and strengthened sympathetic to its age and location, with engagement from stakeholders such as Historic Environment Scotland, SEPA, Nature Scot and Forth Fisheries Trust.

“We would like to thank all local residents and businesses for their patience and understanding during these essential works and we will communicate with them throughout the process. All efforts will be made to re-open the road in a safe manner and at the earliest opportunity.”

Due to adverse weather, which has caused high water levels, works did not recommence as planned on site on 3 February. The dam contractor did return to site on that date, to undertake liner preparatory works.

Due to dam contractor’s availability, works to reinstate the dam at the south pier (pier 1) only recommenced on Monday 17 February. Stirling Council’s appointed, and Nature Scot approved, specialist ecologist oversaw the dam contractor works and undertook ecological works.  Fisheries undertook electro fishing as required. Dam installation was completed on Tuesday afternoon.

Masonry evaluation works were carried out on the south pier (pier 1) on Wednesday. It was determined that 19 stone indents need to be undertaken due to the poor condition of the pier. This number is slightly more than anticipated. Indents above water level at pier 1 were also repaired last week. 

Parapet and cope removal along upstream elevation also commenced last week. Extreme care and consideration is being taken so as to ensure stone can be reused and to prevent against unexpected collapse.

Scour protection works also commenced at pier 1 last week.

Heavy rain overtopped the dam on Thursday. It has now been determined that dam repair works are required to be undertaken prior to works within the dam area recommencing.

Weekend working took place this weekend, with works focusing on the continued take down of parapet and copes along the upstream elevation. Material deliveries also took place over the weekend.

Anchoring works and masonry repair works, above water level, are taking place this week.

Dam contractor to return to site and repair dam.  Masonry repair, anchoring and scour works to be finalised at pier 1. All in water working to be completed. Removal of dam to take place and installation of remainder of main scaffold to take place. Removal of downstream parapet and cope to take place.

On site works due for completion late May 2025. 

Bridge to remain at a fixed road closure for the full duration of the works, with no planned partial or night-time reopening due to health and safety risks.

The next in person community and business engagement events will take place at Port of Menteith village hall on Wednesday 26 March from 11am to 12noon.

The next online community and business engagement events will also be hosted via Microsoft Teams on Wednesday 26 March from 6:30pm to 7:30pm

Our next formal written update will be published here on or before 26 March 2025. 

We would like to thank all local residents and businesses for their patience and understanding during these essential works.