A TEMPORARY crossing will be built next to the Kincardine Bridge as part of a two-year-project to strengthen the structure that holds up the road.

The impressive feat of engineering will see traffic diverted onto it while an 80-metre-long piled viaduct, which was deemed substandard almost 30 years ago, is demolished and replaced with a reinforced concrete version.

Listed building consent was granted recently by Falkirk Council – the work is taking place at the southern end – and Transport Scotland said that, as closure would cause "major congestion", they'll keep Kincardine Bridge open throughout.

The project involves joining the temporary bridge to the current 85-year-old structure and it was planned to begin this summer, only to be pushed back to early next year.

A Transport Scotland spokesperson explained: "The scheme is to demolish the piled viaduct and steel propping system and replace it with a five-span structure replicating the style of the 50-feet spans immediately to the north.

"This will ensure a consistent appearance to the bridge is maintained.

“In order to minimise the impact of the demolition and construction works on road users, a temporary diversion structure with provision for two-way traffic flow will be constructed alongside and to the west of the existing piled viaduct.

"The Kincardine Bridge currently supports two-way traffic flow on a single carriageway.

"Therefore, the temporary diversion structure will continue to maintain two-way traffic flow for the duration of the works.

“Work is expected to commence on site in early 2022 with a duration of 24 months.

"The project has been subject to an environmental impact assessment and listed building consent. In addition, we have made a marine licence application.”

The category A-listed Kincardine Bridge opened to traffic in 1936 and comprises 28 spans of varying forms of construction supported on reinforced concrete piers.

The southern approach is a piled 'jetty'-type structure which was assessed in 1983 as substandard and its replacement was recommended.

Interim measures to provide structural support, in the form of a steel propping system, were installed in 1992 and remain in place.

A report by Jacobs in 2007 said the viaduct should be replaced as it had "insufficient load-carrying capacity, with the deck slab and transverse beams having insufficient strength".

It added that the "original substructure is unsuitable due to the poor condition of the visible portions of the substructure piles" and the steel propping system was "unsuitable for incorporation in the refurbished bridge".

Transport Scotland carried out studies and modelling and said that, by maintaining two-way traffic during the period of the construction works, there should be "no significant delays" at peak times.

Short-term single lane working or full closures of the bridge will be required for specific construction activities, however, this will be limited and "timed to minimise disruption to road users".

Further works proposed for the bridge include: refurbishment of the timber jetties; replacement of the temporary road restraint system with a permanent system; bridge bearing replacement; concrete repairs; and re-painting the bridge.