The cable-stayed bridge carries the A9 Perth to Scrabster dual carriageway over the Beauly Firth.
Works will include resurfacing the entire 1km long bridge deck surface, testing the integrity of the steel deck plates below and safety barrier replacement.
Client Transport Scotland estimates the work will cost around £18m over the course of the 17-month project, which is due to get underway next February.
Contractors will only have a five month window on the bridge to complete works.
Further information at information on the Public Contracts Scotland Web Site .