Councils must base bridge repair decisions on evidence, warns specialist

A structural repair specialist has warned that councils must base decisions on restricted bridges on proper diagnosis, as they wait to hear how the government’s new Structures Fund will be shared out.

Roger Line believes the choice between repairing and replacing ageing structures has to rest on evidence about each bridge. Local highway authorities across England are awaiting decisions on the Department for Transport fund, which offers grants towards repairing or replacing bridges, flyovers, tunnels and other local highway structures.

Awards are due this autumn, and funded schemes must be completed and reopened to traffic by March 2030.

Mr Line, founder and CEO of Structural Repairs, said: “This fund is a real opportunity for councils that have been living with restricted bridges for years. But repair or replace is an engineering decision. It should be based on what each structure actually needs, and the funding should follow that evidence.”

Restrictions are already reshaping journeys in places like Cumbria. Westmorland and Furness Council has bid to the fund to replace Brigsteer and Underbarrow bridges, two 1970s reinforced-concrete half-joint structures over the A591 near Kendal. They were closed in 2024 after structural concerns were identified and reopened under a 3-tonne limit, which was later raised to 7.5 tonnes. Monitoring recorded nearly 30 breaches of the limit in 13 days.

The council says detailed structural analysis by its consultants has confirmed the limit cannot be raised, and the restrictions will stay until the bridges can be replaced. Structural Repairs has not worked on the bridges.

Mr Line said that kind of structure-by-structure assessment was exactly what the funding round should reward.

“A weight limit tells you there’s a concern, but it doesn’t automatically tell you the whole bridge is failing,” he said. “Some restrictions reflect an older structure’s assessed capacity, some reflect damage to one element, and some are there while concerns are investigated. Those are very different starting points.”

Speaking more broadly about ageing concrete bridges, he said the damage people can see is often only part of the story.

“Water, de-icing salts, failed joints and poor drainage can keep attacking the same vulnerable areas for years before anything shows. You have to understand how the deterioration got there, not just where it’s visible. Otherwise you fix the symptom and the cause carries on.”

Structural Repairs carries out extensive work on motorway bridges, where repairs have to be delivered within a live transport network.

Mr Line said the difference between repair and strengthening had to be clear from the outset.

“Reinstating damaged concrete and strengthening a bridge to carry a defined load are different jobs with different design requirements. A neat patch can’t, on its own, justify lifting a weight restriction.”

He added that the pressure to get routes open again must not override the engineering.

“Repairs often have to fit around lane closures or overnight possessions, so the design, materials and contingency plans need to be ready before anyone goes in. But pressure to reopen a route can’t replace the technical decision about whether the work is ready to be accepted.”

Mr Line said councils should treat the funding round as the start of the process, not the end of it.

“Securing the money is one thing. The real test is whether each structure is properly assessed, the work is done for a defined purpose, and it’s handed back with clear evidence of what was done.

“Replacement is sometimes the right answer. But where repair or strengthening is justified, keeping a bridge preserves a route communities rely on. Targeted, well-evidenced work deserves serious consideration before a restriction becomes the most familiar thing about a bridge.”