The long-delayed replacement of worn-out expansion joints under the Forth Road Bridge's carriageways is to go ahead next year.
The £9 million project would see one of the two carriageways closed at a time for up to eight months from spring 2018.
The work was put off until after the opening of the Queensferry Crossing - now due in May - to avoid major traffic disruption.
Once the new bridge is open, the Forth Road Bridge is scheduled to become a "public transport corridor", reserved for buses and taxis.
The Scottish Government's Transport Scotland agency is due to appoint a contractor for the scheme in the autumn.
The 20ft-long main expansion joints beside the bridge's two towers, which expand and contract during temperature changes, have been found to be life-expired
They are believed to be the largest and oldest of their type in existence.
The replacement joints will be a modified version of the same type of joint.
They were originally due to have been replaced in 2010.
It would have involved round-the-clock contraflows during the installation of ramps and mini-bridges to carry traffic over the work area, and lorries being banned from using the bridge.
The ramps and mini-bridges would have cost £6 million alone.
Bridge officials decided to postpone the work after the new bridge was approved, until it was opened and traffic switched from the Forth Road Bridge.
Joints on the north and south approach viaducts and nosing joints at the north and south side towers are also due to be replaced at the same time.