Start of work follows Costain’s award of one of four places on TfL’s £200m framework for early contractor involvement (ECI) and construction. The framework will run for four years.
The full scope of the Hammersmith flyover project will be defined during the ECI phase, but is likely to involve strengthening the flyover using post-tensioning, replacing bearings, waterproofing and resurfacing the deck, and replacing the drainage.
Hammersmith Flyover is used by 90,000 road users a day and is one of the main strategic routes into and out of the capital.
Costain chief executive Andrew Wyllie said: "Costain is delighted to gain a place on TfL's framework, and to commence work on the Hammersmith flyover, which is a technically challenging structure and an important part of London's infrastructure.
"This award further enhances Costain's reputation for innovation and engineering expertise across the whole life cycle of an infrastructure asset, as well as our recognised commitment to providing our customers with certainty of delivery and cost within a collaborative working approach."