Essential work begins on Monday (August 10) underneath one of the main routes into Ellesmere Port.
The £150,000 contract at the landmark Westminster Bridge, funded by the borough council, is expected to last 12 weeks.
The bridge carries the A5032 Whitby Road over the Ellesmere Port to Frodsham railway line.
While major concrete repairs are carried out underneath the bridge, the borough council says there will still be two-way traffic on the bridge with lanes reduced in width. Footways for pedestrians will remain open as usual.
For safety reasons, due to the bridge pier being close to the railway line, some work will be carried out on Saturday nights and early Sunday mornings between midnight and 7am when trains are not running.
History of the bridge
The three span concrete bridge dates back to the early 60s and the bridge deck is made from steel beams encased in concrete. The support piers are made of reinforced concrete and the end abutments are substantially thick, solid concrete.
Local Rossmore ward councillor Pat Merrick (Lab) said: “I know that everyone will be working hard to make sure that the work is finished in 12 weeks.
“Scaffolding will be erected under the bridge during the first week and work will start in earnest soon after that.
“Drivers will see a row of cones and barriers over the bridge, close to the kerb, reducing the width of the road.
“Two way traffic will still be in operation over the bridge and pedestrians will continue to be able to use the footways.”
She added: “The repairs will ensure that the bridge will continue as a main gateway to Ellesmere Port for many years to come.”
Borough roads chief Cllr Brian Clarke (Lab) said: “We apologise in advance because these essential repairs will create noise sometimes at night as the concrete needs to be broken out.
“Everything is also being done to make sure that these essential concrete repairs to the bridge support do not interfere with the busy road traffic or the busy rail network.”
Repairs to a pier at the bridge, said to be in poor condition, were carried out in 2012 after cracking and loose concrete was spotted.
Cllr Lynn Clare (Lab), who now represents Ellesmere Port Town ward, said at the time: “Westminster Bridge carries a main route into the town and is used by thousands of vehicles a day.”